SchillMobiil

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Presentation Transcript

Mobile Communication and Mobile Computing: 

Mobile Communication and Mobile Computing Prof. Dr. Alexander Schill TU Dresden, Computer Networks Dept. http://www.rn.inf.tu-dresden.de

Contents: 

Contents 1. Motivation 2. Mobile Communication History Principles Media Access Methods Mobile Radio Networks: Overview GSM HSCSD, GPRS UMTS

Contents: 

Contents 2. Mobile Communication (Continuation) Broadband-Radio Systems Wireless Local-area Networks (IEEE 802.11, Bluetooth etc.) Satellite-based Systems

Contents: 

Contents 3. Mobile Computing Layer 3 MobileIP v4 & v6 DHCP Layer 4 Higher Layers and Services WAP, XML Mobile RPC CODA, Databases Mobile Agents Middleware for spontaneous networking Services and system support for Mobile Computing

Literature: 

Roth, J.: Mobile Computing, dpunkt-Verlag, 2002 Very good overview to mobile communication and mobile computing Schiller, J., Mobilkommunikation, Techniken für das allgegenwärtige Internet, Addison-Wesley, 2000 Mobile Communication principles and Mobile Computing Bernhard, Walke: Mobilfunknetze und ihre Protokolle, 2 Bände. Teubner, 2000 Principles, GSM, UMTS and other cellular Mobile Radio Networks [Vol.1] Circuit Switched Radio, Cordless Phone Systems, W-ATM, HIPERLAN, Satellite Radio, UPT [Vol.2] Schumny, Harald: Signalübertragung, Friedrich Vieweg & Sohn, Braunschweig/Wiesbaden 1987; Wave propagation and wireless transmission A.S. Tanenbaum: Computernetzwerke, 4. Aufl., Prentice Hall, 1998 Protocols, ISO/OSI, standards, fixed networks Principles Literature

1. Motivation and Examples: 

1. Motivation and Examples

Motivation: 

Speech- and Data Communication location independent and mobile Ä New application areas, flexibility, improved workflows Requirements: - Mobile end-devices - Radio transmission - Localization and signalization/management - Standards - Application Concepts for mobile end-devices in distributed systems - Control of heterogeneous, dynamic infrastructures Mobile Computing Motivation

Application example: Civil Engineering, Field Service: 

Building site Architect Building of enterprise A (main office) Building of enterprise B Construction supervisor X.25 ISDN ATM ATM ISDN GSM GSM Selected drafts, Videoconferences Material data, status data, dates Large archives, Videoconferences Drafts, urgent modification Building of enterprise A (branch office) Application example: Civil Engineering, Field Service

WAP-Example: Order processing: 

WAP-Example: Order processing Order book Status of bond transactions. Executed and deleted orders are indicated in the order book for some days more. Partial execution of some order is presented as one open and one executed partial order in the order book. Details to an order could be indicated via dial-up of correspondent Links.

Perspective: Mobile Multimedia Systems: 

Product Data Main office Caching Client LAN-Access Maintenance technician - very different performance and charges: radio networks versus fixed networks Software-technical, automatic adaptation to concrete system environment Example: Access to picture data/compressed picture data/graphics/text Mobile Access Local Resources, Error Protocols Perspective: Mobile Multimedia Systems

Slide11: 

Ethernet Ethernet Ethernet E-Fax-Order Management DB-Access Firm Branch office Client X GSM xDSL Application Resource Mobile Station Communication path DB Distributed Database Distributed Database Cache Application Structure

Slide12: 

Internet Content Provider Main Office Infrastructure GSM GSM Radio/Infrared ATM GSM, RDS/TMC, DAB ... Beam Radio, ISDN GSM Traffic Telematics Systems Content Provider DAB: Digital Audio Broadcast RDS/TMC: Radio Data System/ Traffic Message Channel

Slide13: 

GSM (Global System for Mobile Communications): worldwide standard for digital, cellular Mobile Radio Networks UMTS (Universal Mobile Telecommunications System): European Standard for future digital Mobile Radio Networks AMPS (Advanced Mobile Phone System): analog Mobile Radio Networks in USA DECT (Digital Enhanced Cordless Telecommunications): European standard for cordless phones TETRA (Terrestrial Trunked Radio): European standard for circuit switched radio networks ERMES (European Radio Message System): European standard for radio paging systems (Pager) 802.11: International standard for Wireless Local Networks Bluetooth: wireless networking in close/local area Inmarsat: geostationary satellite systems Teledesic: planned satellite system on a non-geostationary orbit Mobile Communication Networks: Examples

Slide14: 

Mobile Communication: Development 2005 2000 1995 1990 C Cordless Telephony Mobile Phone Networks Packet Networks Circuit Switched Networks Satellite Networks Local Networks Modacom Mobitex Tetra Inmarsat IR-LAN MBS IMT2000/ UMTS IEEE 802.11/ Hiperlan Radio-LAN Iridium/ Globalstar EDGE GPRS

Used Acronyms: 

Used Acronyms CT2: Cordless Telephone 2. Generation HSCSD: High Speed Circuit Switched Data GPRS: General Packet Radio Service EDGE: Enhanced Data Rates for GSM Evolution IMT2000: International Mobile Telecommunications by the year 2000 MBS: Mobile Broadband System

Slide16: 

2. Mobile Communication

Principles : 

Principles

Slide18: 

Mobile Communication Tied to electro-magnetic radio transmission radio transmission terrestrial orbital (satellite) beam radio broadcast radio equatorial orbit non-equatorial orbit cellular non-cellular Principles: Propagation and reception of electro-magnetic waves Modulation methods and their properties Multiplex methods Satellite orbits/Sight- and overlap areas

Slide19: 

Cellular Networks: Principles Supply- (radius R) and interference areas (5 R) 7-Cell-Cluster (repeat sample of the same radio-channels)

Slide20: 

Cell structure: Example Reference cell Cell in the interference area of the reference cell Further cells, whose channel distribution should be known to the reference cell Cellular Networks: Principles

Kinds of antennas: directional & sectored: 

Kinds of antennas: directional & sectored Energy is radiated in definite directions, for instance x-Direction So called main propagation directions, for instance Satellite Antennas Often also used in Mobile Radio Systems, such as GSM, for creation of sectored cells Seamless radio supply via partial/overlay of sectors x y Directional Antenna Sectored Antenna

Media Access Methods: 

Media Access Methods

Principles: 

Principles Multiplex Multiple-shift usage of the medium without interference 4 multiplex methods: Space Time Frequency Code Media Access Methods controls user access to medium

SDMA (Space Division Multiple Access): 

SDMA (Space Division Multiple Access) based on SDM (Space Division Multiplexing, Space Multiplex) communication channel obtains definite Space for definite Time on the definite Frequency with definite Code Space Multiplex for instance in the Analog Phone Systems (for each participant one line) and for Broadcasting Stations Problem: secure distance (interferences) between transmitting stations is required (using one frequency) and by pure Space Multiplex each communication channel would require an own transmitting station Space Multiplex is only reasonable in combination with other multiplex methods SDMA for instance by base station dedication to an end-device via Media Access Methods or respectively by segmentation of a Mobile Radio Network to several areas

SDMA: Example: 

SDMA: Example k1 k2 s s – secure distance k3 k4 k5 k6 SDMA finds selection f1

FDMA (Frequency Division Multiple Access): 

FDMA (Frequency Division Multiple Access) Based on FDM (Frequency Division Multiplexing, Frequency Multiplex) i.e. to transmission channels several frequencies are permanently assigned, for instance radio transmitting stations k1 k2 k3 k4 k5 k6 f1 f2 f3 f4 f5 f6 s – secure distance s FDMA finds selection

TDMA (Time Division Multiple Access): 

TDMA (Time Division Multiple Access) Based on TDM (Time Division Multiplexing, Time Multiplex) i.e. to transmission channels is the transmission medium is slot assigned for certain time, is often used in LANs Synchronization (timing, static or dynamic) between transmitting and receiving stations is required k1 k2 k3 k4 k5 k6 f1 TDMA finds selection

Combination: FDMA and TDMA, for instance GSM: 

Combination: FDMA and TDMA, for instance GSM GSM uses combination of FDMA and TDMA for better use of narrow resources the used band width for each carrier is 200 kHz t f in MHz 890,2 915 200 kHz 935,2 960 25 MHz 45 MHz 25 MHz uplink downlink

CDMA (Code Division Multiple Access): 

CDMA (Code Division Multiple Access) based on CDM (Code Division Multiplexing, Code multiplex) i.e. to transmission channels the definite Code is assigned, this can be on the same Frequency for the same Time transmitted derivates from military area via development of cost-efficient VLSI components via spread spectrum techniques a good communication security and tiny fault sensitivity but: exact synchronization is required, code of transmitting station must be known to receiving station, complex receivers for signal separation are required Noise should not be very high

CDMA: 

CDMA k1 k2 k3 k4 k5 k6 f1 CDMA decoded

CDMA illustrated by example: 

The Principle of CDMA can be good illustrated by the example of some party: communication partners stand closely to each other, each transmission station (Sender) is only so loud, that it does not interfere to neighbored groups transmission stations (Senders) use certain Codes (for instance, just other languages), they can be just separately received by other transmission stations receiving station (Listener) attunes to this language (Code), all other Senders are realizing this only as background noise if receiving station (Listener) cannot understand this language (Code), then it can just receive the data, but it cannot do anything with them if two communication partners would like to have some secure communication line, then they should simply use a secret language (Code) Potential Problems: security distance is too tiny: interferences (i.e. Polish und Czech) CDMA illustrated by example

CDMA-Example in the theory: 

Sender A Sends Ad =1, Key Ak = 010011 (set: „0“= -1, „1“= +1) Transmit signal As =Ad *Ak = (-1, +1, -1, -1, +1, +1) Sender B sends Bd =0, Key Bk = 110101 (set: „0“= -1, „1“= +1) Transmit signal Bs =Bd *Bk = (-1, -1, +1, -1, +1, -1) Both signals superpose additively in air Faults are ignored here (noises etc.) C = As+ Bs =(-2,0,0,-2,+2,0) Receiver will listen to Sender A uses Key Ak bitwise (internal product) Ae = C * Ak =2 +0+0 +2 +2+0 = 6 Result is greater than 0, so sent bit was „1“ analog B Be = C * Bk =-2 +0 +0 -2 -2 +0 = -6, also „0“ CDMA-Example in the theory

Spread Spectrum Techniques: 

Spread Spectrum Techniques Signal is spread by the Sender before the transmission (overblown) dP/df value corresponds with so called Power Density, Energy is constant (in the Figure: the filled areas) Objective: Increase of robustness against small band-width faults listening security: power density of spread-spectrum signals can be lower than that of background noise

Spread Spectrum Techniques: 

Spread Spectrum Techniques small band-width faults are spread by de-spreading in receiving station band-pass deletes redundant frequency parts t

Mobile Radio Networks: Overview: 

Mobile Radio Networks: Overview

Development of Mobile Radio: 

General technological development in mobile telephony before 1970 1970 1980 2000 2005 Analog Networks...150Mhz 1990 Anal. cellular Networks...450 Mhz Anal. cellular Networks...900 Mhz Digital cellular Networks...900 Mhz Digital cellular Networks...1800 Mhz GSM Phase II+ UMTS Satellite Systems (LEO) Prognoses Development of Mobile Radio

Slide37: 

Correspondent data rates (GEO) Satellites (GEO)

Participant quantities in Mobile Radio – world-wide: 

Participant quantities in Mobile Radio – world-wide November 2002: 1148 Mio. participants world-wide (1119 Mio. digital & 29 Mio analog) 1... Europe: Western 4... Americas (thereof 15.4 Mio. analog) 2... Asia Pacific 5... USA/Canada (thereof 5.4 Mio. analog) 3... Middle East 6... Africa 7… Europe: Eastern (Source: http://www.emc-database.com)

Frequency Assignment: 

Frequency Assignment TETRA 380-400 410-430 NMT 453-457 463-467 CT2 864-868 CT1+ 885-887 890-915 GSM900 CT1+ 930-932 GSM900 935-960 TFTS (Pager, aircraft phones) GSM1800 1670-1675 1710-1785 1800-1805 TFTS 1805-1880 GSM1800 DECT 1880-1900 (1885-2025 2110-2200) TETRA 450-470 (nationally different) UMTS IEEE 802.11b 2400-2483 HIPERLAN1 5176-5270 MHz Bluetooth 2402-2480 HIPERLAN2 (ca.5200,5600) WLAN 2412-2472 HomeRF...(approx.2400) Circuit Switched Radio Mobile Phones Cordless Phones Wireless LANs Notes: - 2,4 GHz license free, nationally different - () written : Prognoses! - today speech over license free frequencies up to 61Ghz -> interesting for high data rates (ca.17000) HIPER-Link 1GHz 500Mhz TFTS - Terrestrial Flight Telephone System IEEE 802.11a: 5,15-5,25; 5,25-5,35; 5,725-5,825

Broadcast/multicast networks: 

Broadcast/multicast networks several carrier frequencies but participant obtains carrier for short time only often in use by taxi- und logistics enterprises etc., each own separated frequency reaches can use the same frequency packs with FDM- and TDM- techniques, i.e. more efficient handling with narrow resource frequency spectrum improves transition to fixed network, speech- and data services not for public access very reliable, cost-efficient

TETRA (Terrestrial Trunked Radio): 

TETRA (Terrestrial Trunked Radio) former name: Trans-European Trunked Radio frequencies: 380-390, 410-420 MHz Uplink; 390-400, 420-430 MHz Downlink bandwidth of each channel: 25 kHz 1991 started by ETSI replace of national networks like MODACOM, MOBITEX or COGNITO Services: Voice + Data (V+D)- Service: Speech and Data, channel-oriented, uni-, multi- and broadcast possible Packet Data Optimized (PDO)- Service: packet-oriented, improves connection-oriented or connectionless service, as well as point-to-point and point-to-multipoint communication carrier services with data rate up to 28,8 kbit/s unprotected; 9,6 kbit/s - protected

TETRA, advantages compared with GSM, UMTS: 

TETRA, advantages compared with GSM, UMTS confirmed and/or non-confirmed Group Call (however it’s already possible with GSM today: up to 16 participants) Group call listening is possible (so called “open-channel mode”) very reliable fast dialing: approx. 300 ms (so called “push to talk”), GSM: several seconds certain independence of infrastructure (so called “direct mode” between end-devices) cost-efficient, especially for limited user quantity, because of the „large“ cells x • 10 km also especially suitable for emergency teams (fire department, ambulance etc.)

Cordless Telephony - DECT (Digital Enhanced Cordless Telecommunications): 

Cordless Telephony - DECT (Digital Enhanced Cordless Telecommunications) frequency reach: 1880 - 1990 MHz other than GSM limited to short reaches (1km) in buildings particularly under 50m is not designed for use at high rates mobile phones with GSM and DECT are available in the market 120 full duplex channels TDD (Time Division Duplex) for directional separation with 10ms frame length frequency reach is divided into 10 carrier frequencies using FDMA each station 10mW averaged, max. 250mW of transmitting power, GSM – radio phones transmit at 1 to 2W, fixed car phones up to 8W

DECT – system architecture: 

PA PA PT PT FT FT D4 D3 D2 Local Networks Local Networks HDB VDB Global Networks D1 FT.. Fixed Radio Termination PT.. Portable Radio Termination PA... Portable Terminations HDB.. Home Data Base VDB.. Visitor Data Base DECT – system architecture

DECT - Multiplex: 

64 bit 8 bit 160 bit 48 bit 32 bit Synchronization Signalization Used Data (Speech) CRC Used Data (Speech) CRC Secure marker 160 bit 8 bit 0,417 ms DECT-timeslot structure Transmission reach of fixed part (downlink) Transmission reach of mobile part (uplink) carrier frequency 1: 1 2 3 4 5 6 .... 11 12 1' 2' 3' 4' 5' 6' .... 11' 12' 1 2 3 4 5 6 .... 11 12 1' 2' 3' 4' 5' 6' .... 11' 12' 1 2 3 4 5 6 .... 11 12 1' 2' 3' 4' 5' 6' .... 11' 12' 1728 kHz Transmission principle of DECT-system Channel 1 Channel 2 Channel 12 Channel 1’ Channel 2' Channel 12' . . . . . . fixed part to mobile part mobile part to fixed part Time duplex with 10 ms frame length Structure of DECT-time multiplex frame DECT - Multiplex carrier frequency 2: carrier frequency 10:

Slide46: 

Eurosignal to each participant 4 different audio signals using 4 diverse call numbers are assigned. Meaning must be agreed. Receiving stations are at a size of a cigarette packet 85 senders in the 87 MHz-reach (ultra short waves) called person location must be approximately known: 3 area codes: North 0509, Middle 0279, South 0709 Cityruf (city call) additionally to 4 audio- or respectively optical signals transmission of short numerical (15 digitals) or alpha-numerical messages (80 characters) exists optionally, receiving station is smaller than with Eurosignal PEP (Pan European Paging) preparation for coupling of national services for ERMES D: Cityruf, F: Alphapage, GB: Europage, I: SIP ERMES (European Radio Message System) ETSI-Standard for pan-European radio service, similar to PEP but in 169 MHz-reach with 60 Mio. addresses Pager systems: overview

GSM: Global System for Mobile Communications: 

GSM: Global System for Mobile Communications

GSM: Properties: 

GSM: Properties cellular radio network (2nd Generation) digital transmission, data communication up to 9600 Bit/s Roaming (mobility between different net operators, international) good transmission quality (error detection and -correction) scalable (large number of participants possible) Security mechanisms (authentication, authorization, encryption) good resource use (frequency and time division multiplexing) integration within ISDN and fixed network standard (ETSI, European Telecommunications Standards Institute)

Providers in Germany (1): 

Providers in Germany (1) D1 T-Mobile subscribers: 24,6 Mio (Stand 2003) Vodafone D2 old name: Mannesmann Mobilfunk D2 subscribers: 22,7 Mio (Stand 2003) E-plus O2 old name: VIAG Interkom

Providers in Germany (2): 

Providers in Germany (2)

GSM: structure: 

AuC Authentication Centre BSS Base Station Subsystem BSC Base Station Controller BTS Base Transceiver Station EIR Equipment Identity Register HLR Home Location Register MS Mobile Station (G)MSC (Gateway) Mobile Switching Centre OMC Operation and Maintenance Centre PSTN Public Switched Telephone Network VLR Visitor Location Register ISDN Integrated Services Digital Network Fixed network Switching Subsystems VLR Radio Subsystems HLR AuC EIR (G)MSC OMC BTS BTS BSC BSS Data networks PSTN/ ISDN MS GSM: structure

Slide52: 

GSM: Structure Operation and Maintenance Centre (OMC) logical, central structure with HLR, AuC und EIR Authentication Centre (AuC) authentication, storage of symmetrical keys, generation of encryption keys Equipment Identity Register (EIR) storage of device attributes of allowed, faulty and jammed devices (white, grey, black list) Mobile Switching Centre (MSC) arrangement centre, partial as gateways to other nets, assigned to one VLR each Base Station Subsystem (BSS): technical radio centre Base Station Controller (BSC): control centre Base Transceiver Station (BTS): radio tower / antenna

Slide53: 

1 TDMA-Frame, 144 Bit in 4,615 ms 8 TDMA-channels, together 271 kBit/s inclusive error protection information 124 radio frequency channels (carrier), each 200 kHz 2 frequency wavebands, for each 25 MHz, divided into radio cells 890 935 915 MHz 960 MHz downlink uplink Radio technical structure One or several carrier frequencies per BSC Physical channels defined by number and position of time slots

Slide54: 

GSM: protocols, incoming call VLR BSS BSS MSC GMSC HLR BSS BSS (4) (2) (4) (5) (3) (10) (6) (11) (7) (8) (8) (9) (12) (8) (1) (12) (9) (8) (1) Call from fixed network was switched via GMSC (2) GMSC finds out HLR from phone number and transmits need of conversation (3) HLR checks whether participant for a corresponding service is authorized and asks for MSRN at the responsible VLR (4) MSRN will be returned to GMSC, can now contact responsible MSC

Slide55: 

GSM: protocols, incoming call VLR BSS BSS MSC GMSC HLR BSS BSS (4) (2) (4) (5) (3) (10) (6) (11) (7) (8) (8) (9) (12) (8) (1) (12) (9) (8) (5) GMSC transmits call to current MSC (6) ask for the state of the mobile station (7) Information whether end terminal is active (8) Call to all cells of the Location Area (LA) (9) Answer from end terminal (10 - 12) security check and connection construction

Slide56: 

GSM: protocols, outgoing call (1) Demand on connection (2) Transfer by BSS (3-4) Control for authorization (5) Switching of the call demand to fixed net

GSM: channel strucure: 

GSM: channel strucure Traffic Channel speech- / data channel (13 kbit/s brutto; differential encoding) units of 26 TDMA - Frames Half-rate traffic channel: for more efficient speech encoding with 7 kbit/s Control Channel Signal information Monitoring of the BSCs for reconnaissance of Handover Broadcast Control Channel BSC to MS (identity, frequency order etc.) Random Access Channel Steering of channel entry with Aloha-procedure Paging Channel signalize incoming calls

Slide58: 

Databases Home Location Register (HLR), stores data of participants, which are reported in an HLR-area Semi-permanent data: Call number (Mobile Subscriber International ISDN Number) - MSISDN, e.g. +49/171/333 4444 (country, net, call number) identity (International Mobile Subscriber Identity) - IMSI: MCC = Mobile Country Code (262 for .de) + MNC = Mobile Network Code (01-D1, 02-Vodafone-D2, 03-eplus, 07-O2) + MSIN = Mobile Subscriber Identification Number Personal data (name, address, mode of payment) Service profile ( call transfer, Roaming-limits etc.) Temporary data: MSRN (Mobile Subscriber Roaming Number) (country, net, MSC) VLR-address, MSC-address Authentication Sets of AuC (RAND (128 Bit), SRES (128 Bit), KC (64Bit)) charge data

Slide59: 

Databases Visitor Location Register (VLR) local database of each MSC with following data: IMSI, MSISDN service profile accounting information TMSI (Temporary Mobile Subscriber Identity) - pseudonym for data security MSRN LAI (Location Area Identity) MSC-address, HLR-address

Slide60: 

MSC-area = VLR-area LA = smallest addressable unit Handover GSM: mobile telephone areas

Slide61: 

MSC-area HLR VLR Location area advantage of the architecture: Location Update at limited mobility, as a rule only at VLR, rarely at (perhaps far remote) HLR Connection HLR, VLR

Slide62: 

LA 5 LA 3 LA 2 LA 3 0x62F220 01E5 z.B. Localization at GSM

Data transmission: 

Data transmission each GSM-channel configurable as a data channel; similar structure like ISDN-B and -D-channels data rates up to 9600 bit/s now delay approximately 200 ms speech channels have as a rule higher priority as data channels kinds of channels: transparent (without error correction; however FEC; fixed data rate; error rate 10-3 up to 10-4) non-transparent (repeat of faulty data frames; very low error rate, but also less throughput) Short-Message-Service (SMS) connectionless transmission (up to 160 Byte) on signal channel Cell Broadcast (CB) connectionless transmission (up to 80 Byte) on signal channel to all participants, e.g. one cell

Slide64: 

MSC BSC UDI BTS IWF TA ISDN Modem PSTN Internet Modem IWF - Inter Working Function UDI - Unspecified Digital TA - Terminal Adapter Data transmission - structure

Slide65: 

Chip-card (Smart Cart) to personalize a mobile subscriber (MS): IMSI (International Mobile Subscriber Identity) participant special symmetric key Ki, stored also at AuC algorithm “A3” for Challenge-Response-Authentication algorithm “A8” for key generation of Kc for content data PIN (Personal Identification Number) for entry control Temporary data: TMSI (Temporary Mobile Subscriber Identity) LAI (Location Area Identification) Encryption key Kc Security aspects: Subscriber Identity Module (SIM)

Security in GSM-networks: 

Security in GSM-networks SIM Entry control and cryptographic algorithms Single-sided authentication (participant against network) Challenge-Response-method (cryptographic algorithm: A3) Pseudonyms of participants at the Radio interface Temporary Mobile Subscriber Identity (TMSI) Connection encoding on the Radio interface Key generation: A8 Encryption: A5

Slide67: 

Security aspects: Authentication MSC, VLR, AuC MS Authentication Request RAND (128 Bit) Random number generator A3 SRES SRES (32 Bit) A3 Authentication Response = Location Registration Location Update with VLR-change Call setup (in both directions) SMS (Short Message Service) max. 128 Bit

Security aspects: Session Key: 

Security aspects: Session Key Netz MS Authentication Request RAND (128 Bit) Random number generator A8 A8 64 Bit Key generation: Algorithm A8 Stored on SIM and in AuC with Ki parametric one way function no (Europe, world wide) standard can be determined by net operator Interfaces are standardized combination A3/A8 known as COMP128

Slide69: 

Security aspects: encryption at the Radio interface Net MS Ciphering Mode Command A5 A5 Data encryption through algorithm A5: stored in the Mobile Station standardized in Europe and world wide weaker algorithm A5* or A5/2 for specific countries TDMA-frame- number TDMA-frame- number Key block Plain text block Plain text block Ciphering Mode Complete Encrypted Text 114 Bit

GSM-Security: assessment: 

GSM-Security: assessment cryptographic methods secret, so they are not „well examined“ symmetric procedure consequence: storage of user special secret keys with net operators required low key length Ki with max. 128 Bit (could be hacked by using Brute Force Attack in 8-12 hours) no mutual authentication intended consequence: Attacker can pretend a GSM-Net no end-to-end encryption no end-to-end authentication Key generation and -administration not controlled by the participants

GSM Phase II+ HSCSD, GPRS: 

GSM Phase II+ HSCSD, GPRS

Slide72: 

HSCSD: High Speed Circuit Switched Data

Properties: 

higher data rate because of channel bundling parallel usage of several time slots (TCH) of one frequency on Um more efficient channel encoding (14,4 kbit/s per TCH) Data rates from 9,6 up to 53,8 kbit/s asymmetric transmission (1TCH Uplink / 3TCH Downlink) Properties

HSCSD data rates: 

HSCSD data rates transparent non transparent up- / downlink 100% coverage 95% coverage 100% coverage 95% coverage 1 + 1 9,6 14,4 9,6 13,2 2 + 2 19,2 28,8 19,2 26,4 1 + 3 --- ---- 28,8 39,6 1 + 4 --- ---- 38,4 53,8

HSCSD: structure: 

MSC BSC UDI BTS IWF TA ISDN Modem PSTN Internet Modem IWF - Inter Working Function UDI - Unspecified Digital TA - Terminal Adapter n time slots (TCH) of each TDMA frame (theoretically max. 8) HSCSD: structure

HSCSD: changes: 

Um Abis A MSC BSC BTS n time slots (TCH) of each TDMA frame (theoretically max. 8) multiplex of the time slots on each 64 kBit/s channel certain changes are necessary at the component several changes at the software/firmware minimal changes at the software/firmware HSCSD: changes

HSCSD radio interface: 

parallel usage of several time slots limited to one frequency Cost factor limits number of used TCH‘s to (2+2) or (1+3, uplink, downlink) Required time for setting to receiving standby 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 Required time for setting to transmission standby Required time for signal strength measure and setting to receiving standby MS RECEIVE MS TRANSMIT MS MONITOR HSCSD radio interface

Assessment of HSCSD: 

Assessment of HSCSD existing net structure and accounting model maintained in comparison to GPRS only around1/5 of investment necessary HSCSD is still circuit switched has defined QoS- settings (data rate, delay) one logical channel will be switched on all interfaces for the time of the connection Non-efficient for burst-like traffic (Internet) or Flat Rate billing (Logistics) no international acceptance (Roaming!) uses also more resources on the radio interface problems with handover into a new cell

Slide79: 

GPRS: General Packet Radio Service

Properties: 

Properties Packet switching service (end- to- end) Data rates up to 171,2 kbit/s (theoretical) Effective and flexible administration of the radio interface adaptive channel encoding Internetworking with IP- and X.25 nets standardized dynamic sharing of resources with „classical“ GSM speech services Advantage: Billing and Accounting according to data volume Disadvantage: cost intensive additional net hardware necessary

Properties: 

Properties point-to-point-Packet transfer service PTP-CONS (PTP Connection oriented Network Service) connection oriented, similar to X.25 PTP- CLNS (PTP Connectionless Network Service) connectionless, similar to IP point- to- multipoint - group communication

Slide82: 

MSC BSC BTS Internet GPRS: Structure HLR GSM GPRS Backbone Frame Relay / ATM GGSN GGSN SGSN Border Gateway other packet switching networks

GPRS: Changes: 

GMSC Circuit switched traffic HLR/AuC GPRS register MAP MAP A GGSN GPRS: Changes Abis Gb Gn Gi public remote fixed nets Packet arranged traffic Gs Um n time slots (TCH) per TDMA frame (theoretically max. 8) per packet! PCU - Packet Control Unit SGSN MSC BSC BTS PCU

Tasks: SGSN, GGSN: 

SGSN: - mobility management - session management - QoS - security External Data Domain Intranet SGSN HLR Internet MAP Signalization (SGSN) Tasks: SGSN, GGSN BSS PCU BSS PCU BSS PCU Client GGSN Client Server MAP Signalization (GGSN) SGSN, GGSN: - Routing - Signalization - Resource management SGSN

Tasks of the SGSN: 

Tasks of the SGSN Packet delivery mobility management apply/ sign off of terminals localization LLC (Logical Link Control) management authentication billing

Tasks of the GGSN: 

Tasks of the GGSN mediator between GPRS backbone and external data networks (Internet, X-25 etc.) converts GPRS packets, data Protocol (PDP) into the corresponding structure also converts PDP addresses of incoming packets into GSM address of the receiver saves current data for the SGSN address of the participant as well as their profile and data for authentication and invoice

GPRS: air interface: 

Radio Link Control (RLC) Segmentation of the LLC-Frames in RLC blocks Block size dependent on short-term channel conditions Backward error correction and data flow control by Automatic Repeat Request (ARQ) protocol repeating not repairable RLC blocks selectively Medium Access Control ( MAC) Channel reservation contains: - one/several time slots (Packet Data Channels PDCH) of one frequency one uplink status flag (USF) per Packet Data Channel (PDCH), channel partition of up to 8 ms GPRS: air interface

GPRS: air interface: 

Medium Access Control ( MAC) Reservation in the uplink (MS to BSS): MS sends reservation request on a Random Access Channel (Slotted ALOHA) BTS allocates a (split) channel and sends packet assignment MS sends data depending on the current priority (USF flag) Reservation in the Downlink (BSS to MS): BTS displays transmitting request and informs about the reserved channel MS supervises the reserved channel and receives GPRS: air interface

GPRS: air interface: 

Physical Link Control adaptive forward error correction (FEC) dependent on short-term channel conditions temporal scrambling (Interleaving) of the bursts and Mapping on reserved PDCH (Packet Data Channel) procedure to recognize overbooking situations on the physical channel GPRS: air interface GPRS Channel Encoding

Quality of Service: 

Quality of Service QoS profile agrees service parameters inside the whole network Agreed for the duration of one PDP (Packet Data Protocol) context (session, end terminal is obtainable for the duration of the context, e.g. obtainable over Internet ) : temporary address (IP) for mobile station tunneling information, among others GGSN, which is used for access to corresponding packet arranged network type of the connection QoS profile QoS profile commits: precedence class, priority against other services (high, normal, low) packet delay class, times are valid for traffic inside the GPRS- network reliability class peak throughput class mean throughput class

Quality of Service: 

Quality of Service Packet delay classes Security classes

Slide92: 

Quality of Service GPRS- using data rates CS 3 and CS 4 are only reasonable in the second phase of GPRS introduction They will be used adaptively at corresponding good quality of radio connection CS 4 does not comprise error correction, code rate = 1!

Assessment of GPRS: 

Assessment of GPRS An up to 4 times higher data rate in comparison to ordinary GSM- data services better resource management through packet arranged service „always on” data service (email, etc.) GPRS is a more suitable carrier for services like WAP - IP-derivate, no true guaranties (QoS) - development of the network infrastructure is relatively expensive, particularly regarding introduction to UMTS (return of investment) - GPRS doesn’t give such data rates like advertising has sometimes promised

Slide94: 

9.6 kbit/s Data rate 26.4 kbit/s 13.2 kbit/s HSCSD Channel packing, NT 39.6 kbit/s CS 1 GPRS Packet arranged 9 kbit/s 18.1 kbit/s 27.2 kbit/s 13.4 kbit/s 26.8 kbit/s 40.2 kbit/s CS 2 Development of the GSM-data services flow

Enhanced Services - EMS (enhanced message service): 

Enhanced Services - EMS (enhanced message service) Uses widespread existing infrastructure (SMS) new Mobile telephones necessary allows sending and receiving of messages with formatted texts, melodies, graphics (32 x 32 Pixel) and animations (16 x 16 Pixel) – e.g. NOKIA new applications like Mobile Ticketing tickets will be transferred to mobile phone like a bar code and checked at the admission EMS enables transition to MMS (multimedia messaging service), which allows transmission of multimedia enriched messages over UMTS-Network (photos, parts of videos) MMS requires new network elements in the Infrastructure of the operators

MMS - architecture: 

MMS - architecture . . . MMS Relay MMS User Agent MMS User Databases MMS Server (e.g. E-Mail) MMS Server (other service) alien MMS Relay SMTP LDAP GSM-MAP or IS-41-MAP or TCP/IP SMTP, HTTP, POP3, IMAPv4 WAP or MExE (e.g. Java and TCP/IP) HLR MMS Server (e.g. Fax) Based on materials from 3GPP, http://www.3gpp.org

Slide97: 

UMTS: Universal Mobile Telecommunications System, 3G, 3rd generation of mobile radio

IMT-2000 - structure: 

IMT-2000 - structure source: www.UMTS-Report.com 3 systems - UMTS - CDMA2000 - UWC-136 2 core technologies - TDMA - CDMA satellite- supported network expansion: - SW-CDMA: Satellite Wideband CMDA - SW-CDTMA: Satellite Wideband CDMA/TDMA (Hybride procedure) - SAT-CDMA: Satellite CDMA - ICO RTT: ICO Radio Transmission Technology IMT-2000 family of radio interfaces : IMT-DS (Direct Spread) UTRA-FDD (UMTS) IMT-MC (Multi Carrier) CDMA2000, USA IMT-TC (Time Code) UTRA-TDD (UMTS), TD- SCDMA (Synchronous Code Division Multiple Access, China) IMT-SC (Single Carrier) UWC-136, USA IMT-FT (Frequency time) DECT IMT-2000 TDMA CDMA individual carrier multiple carrier IMT-SC IMT-FT TDD IMT-DS IMT-MC UWC-136 (EDGE) DECT UTRA-FDD CDMA2000 UTRA-TDD TD-SCDMA FDD IMT-TC ICO RTT... Standard by ICO Global Communications IMT ... International Mobile Telecommunications UTRA ... Universal Terrestrial Radio Access UWC ... Universal Wireless Communications In europe UMTS

Slide99: 

Worldwide frequency assignment for IMT-200 developed by ITU PCS... Personal Communication System MSS...Mobile Satellite Service PHS... Personal Handy-Phone System

UMTS - Facts: 

UMTS - Facts consideration: early 90ies Universal Mobile Telecommunications System, developed in the EU (ETSI: European Telecommunication Standards Institute) UMTS is the European implementation of IMT-2000 (International Mobile Telecommunications by the year 2000) Start of network expansion: in Europe: 2003 (some trials, e.g. British Telecom on Isle of Man, 2002) in the USA: 2005 in Japan since 2000 : NTT DOCOMO

Frequency award in Europe: 

1700 1750 1800 1850 1900 1950 2000 2050 2100 2150 2200 GSM1800 Uplink GSM1800 Downlink DECT FDD Uplink FDD Downlink TDD TDD MSS MSS 230 MHz frequency range for IMT-2000 at FDD symmetrical spectrum is necessary, not at TDD (time slots at same frequency) gradual new assignment of wavebands depending on development of the need up to 300-500 MHz frequency range in 2008 Frequency award in Europe source: www.UMTS-Report.com MSS…Satellite- based

Characteristics: 

system general , worldwide roaming high data rates: 144 kbit/s mobile, up to 2 Mbit/s at local area fusion of different mobile radio communications-, wireless- and pager-systems into one common system speech-, data-, and multimedia- information services independent of used network access support of different carrier services: real-time capable/not real-time capable circuit switched/ packet switched Roaming also between UMTS and GSM and satellite networks Asymmetrical data rates in up-/downlink Characteristics

UMTS- Disadvantages: 

UMTS- Disadvantages Technology not yet perfect rent ability of pico cells („Hotspots“) not yet analyzed strong contention by WLAN increased radiation exposure high data rate only obtainable sometimes (High-Tech-network expansion, stationary and exclusive usage necessary!) because of high license costs high charges necessary (around double GSM-costs)

UMTS - Performance: 

UMTS - Performance ~ 0 sec 10 sec 1 min 10 min 1 h UMTS GPRS ISDN PSTN GSM Web Web Web Web Photo Photo Photo Photo Photo Mail Mail Mail Report Video Report Video Report Video Video Report source: Mobilkom Austria

UMTS - Hardware: 

UMTS - Hardware big color displays high resolution True Color

UMTS- cell structure: 

UMTS- cell structure Quelle: Mobilkom Austria Gateway Mobile Switching Centre 3G Mobile Switching Centre Home Location Register Gateway GPRS Support Node Internet customer Intranet packet- switched BTS BTS BTS BTS BTS BTS BTS BTS BTS GSM - BSS UTRAN- UMTS Terrestrial Radio Access Network Base Station Controller Radio Network Controller Radio Network Controller Radio access network PSTN/ ISDN UMTS-Core Network Visitor Location Register circuit switched 3G- Serving GPRS Support Node

UMTS: cell structure: 

Zone1: In-building “Pico cell” Zone 2: Neighborhood “Micro cell” Zone 3: Suburban “Macro cell” Zone 4: Global Satellite UMTS: cell structure “World cell”

UMTS: hierarchical cell structure: 

Global Lokal Regional Home/ Office World Macro Micro Pico UMTS: hierarchical cell structure principle: - all neighbor cells use same frequency channel - only one waveband is necessary for cellular construction - further wavebands are necessary for hierarchical structure

Classification : 

Classification

Service concept: 

Virtual Home Environment (VHE): offered services are freely configurable, configuration still exists in the whole network choose of service quality and also arising costs behave at bottlenecks (data rates, etc.) configurable dynamic customization to connection Service concept

Slide111: 

one phone number for several devices (Call- Management) subscriber localization e.g. with SIM-card call passing virtual mobility of fixed networks UPT: Universal Personal Telecommunication Service

Intelligent networks: 

Intelligent networks Implementation of basic services like subscriber localization billing etc. supply of value added service (Voice-Mailbox, etc.) possibility of easy, fast introduction of new services flexible service administration usage of services also from foreign network possible better control of service parameters through subscriber

UMTS: basic network structure: 

UMTS: basic network structure Access Network: base stations, responsible for radio contact to mobile end devices Core Network (Fixed Network): responsible for structure of connections Intelligent Network (IN): responsible for billing, subscriber localization, Roaming, Handover Intelligent Network Core Network Access Network User Equipment (UE)

General reference architecture: 

General reference architecture UTRA: UMTS Terrestrial Radio Access UTRAN (UTRA- Network) contains several radio subsystems, so called Radio Network Subsystems (RNS) and contains functions for mobility management RNS controls handover at cell change, capacitates functions for the encoding and administrates the resources of the radio interface Uu connects UTRAN with mobile end devices, so called User Equipment (UE), is comparable with Um in GSM UTRAN is connected over Iu with the Core Network, comparable with the A interface in GSM between BSC and MSC CN contains the interfaces to other networks and mechanisms for connection handover to other systems

The UMTS-radio interface UTRA (UMTS Terrestrial Radio Access): 

The UMTS-radio interface UTRA (UMTS Terrestrial Radio Access) Two modes defined: UTRA/FDD (Frequency Division Duplex) mainly in suburban areas for symmetrical transmission of speech and video data rates up to 384 kbit/s, supra-regional roaming for circuit- and packet switched services in urban areas UTRA/TDD (Time Division Duplex) mainly in households and other restricted areas (company's premises, similar to DECT) for broadcast of speech and video, both symmetrical: up to 384 kbit/s also asymmetrical: up to 2 Mbit/s

UTRA/FDD: 

UTRA/FDD puts wide- band- CDMA (W-CDMA) together with DSSS (Direct Sequence Spread Spectrum) as spread spectrum technique channel separation by carrier frequencies, spreading code and phase position (only uplink) ca. 250 channels for used data, data rates up to 2 Mbit/s complex performance control necessary

UTRA/TDD: 

UTRA/TDD puts wideband- TDMA/CDMA together with DSSS sends and receives on same carrier (TDD) ca. 120 channels for used data, data rates up to 2 Mbit/s channel separation by spread code and time slots less spreading than at FDD precise synchronization necessary lower demand for performance control

Slide118: 

Extension Band 1 (worldwide similar) – partly terrestrial, partly satellite- based Extension Bands (for a future market potential ..from 2005) Frequency award for UMTS

UMTS-licenses in Germany: 

UMTS-licenses in Germany E-Plus Hutchison 8.394.492.363 € Group 3G 8.408.706.278 € Vodafone (Mannesmann Mobilfunk) 8.422.920.192 € MobilCom Multimedia 8.369.848.095 € T-Mobil 8.478.344.232 € O2 (VIAG Interkom) 8.445.008.001 € 17.08.2000: each license got 2 x 5 MHz packets, 60 MHz have been given away altogether, 150 MHz are available altogether RegTP determined: - till end of 2003 25 % network coverage - till end of 2005 50 % network coverage

Summary: 

Summary introduced variants are the proposals, which will be supported by Europe, Japan and partly by the USA worldwide accessibility can be realized only with multimode end devices even in Europe combined UTRA-FDD/UTRA-TDD/GSM- devices are necessary (those are realized by the identical frame time of 10ms at relatively low costs)

Slide121: 

Wireless Local Networks, WLAN

Why do we need wireless LANs?: 

Why do we need wireless LANs? Advantages flexibility Ad-hoc-network realizable with less expenditure No problems with cables Disadvantages high error vulnerability on the transmission link in comparison to Standard-LANs National restrictions, no international standards at used frequency bands (Industrial Scientific Medical (ISM)- Band) security, costs

Application areas: 

Application areas networks in exhibition halls hospitals warehouses airports structure of networks in historic buildings extension of existing wired local area networks in offices, universities etc.

Problems with the use of WLAN‘s: 

Problems with the use of WLAN‘s physical problems interference: band spreading echo: use of special antennas Hidden Terminal problem: use CSMA/CA data security Wired Equivalent Privacy (WEP) service further development WiFi (Wireless Fidelity), WPA (WiFi Protected Access)

Standards: 

Standards IEEE 802.11 (a,b,g ; optional e,h,i) frequency band 2,4 GHz, also in the 5GHz - band data rates: 1 bis 11 Mbit/s (at present, later up to 20 (2,4 GHz) or 54 Mbit/s (5,4 GHz)) WiFi: Wireless Fidelity, certificate from the WECA (Wireless Compatibility Allicance), secures the interoperability between the Radio- LANs and contains improved security mechanisms HomeRF Bluetooth (IEEE 802.15) Frequency band: 2,4 GHz Data rate: 1 Mbit/s; in the future also 20 Mbit/s connection of peripherals HIPERLAN (ETSI) / Wireless ATM frequency bands 5,15 / 5,30 GHz and 17,1 / 17,3 GHz data rates: 24 Mbit/s or 155 Mbit/s however no practical relevance

IEEE 802.11b: 

IEEE 802.11b frequency: 2,4 GHz frequency band, also called ISM (= Industrial Scientific Medical Band), not regulated 850 - 950 nm at infrared transmission power: min. 1mW max. 100mW in Europe (1W in the USA) reach: of 10m (IR) to 30km or more with the help of special antennas (directional antennas)

Basic WLAN- structure: 

Basic WLAN- structure Ad-hoc-network: 3 connected infrastructure networks: AP - Access Point

System architecture IEEE 802.11: 

System architecture IEEE 802.11 Distribution System 802.x LAN 802.11 LAN STA1 Access Point Portal BSS1 Access Point STA2 STA3 802.11 LAN BSS2 ESS

System architecture IEEE 802.11, concepts: 

System architecture IEEE 802.11, concepts Station (STA) device with 802.11- concurring interface Access Point allows the access to the distribution system for registered stations and secures accessibility of the stations also beyond the BSS Coordination Function (CF) logical functional unit, which decides when a station can send Basic Service Set (BSS) consists of several stations, that were controlled by an CF, e.g. BSS2 and STA2, STA3

System architecture IEEE 802.11, concepts : 

System architecture IEEE 802.11, concepts Distribution System connects several BSS over access points and forms a logically larger net Extended Service Set (ESS) Radio networks, which are connected over Distribution System Portal allows transition into other networks

Overview: 

Overview 802.11 is the most frequently used solution for wireless connection; very strong distribution on the market interesting future option: „Seamless Handover“ between GSM and IEEE 802.11; supported by Cisco, Intel etc. (alternative to UMTS?) higher data rates already standardized or in use 802.11a: physical layer at 5 GHz – Band, data rates up to 54 MBit/s 802.11b: extension to physical layer for the 2,4 GHz – band, data rates up to 11 MBit/s, products available 802.11g: at present the industry works on an extension, shall allow the up to 54Mbit/s in the frequency band around 2.4 GHz Study Group 5GSG: examines the harmonization between IEEE 802.11 and ETSI HiperLAN Task Group e: MAC functions for QoS-Management and to refine improved safety functions, introduction of service classes etc.

802.11 – Norms for WLAN: 

802.11 – Norms for WLAN

Example: Lucent Wavelan 802.11b WLAN Card: 

Example: Lucent Wavelan 802.11b WLAN Card Wireless connection that acts just like a conventional Ethernet link Technical specifications: 11 Mbps wireless connection 40-bit WEP or 104-bit RC4 link layer encryption Interoperability with other cards of IEEE 802.11b (i.e. Cisco Aironet or the Apple Airport Card) Tiny size - a PCMCIA card less than 1 inch Cross-platform support (Linux, Mac, and Win*) Very low cost (comparable to a PCMCIA 10/100 Ethernet card) http://www.lucent.com/

Example: Globalsuntech 802.11b products: 

Example: Globalsuntech 802.11b products Bit rates: 22/11/5.5/2/1 MBit/s per channel WEP 64/128/256 Bit Available devices: Card Bus PCMCIA Card PCI Card Mini USB DSSS; selectable channels: USA, Canada - 11 channels Europe - 13 channels Japan - 14 channels Sensitivity, range: 80dBm for 22MBit/s 92dBm for 1MBit/s Cross-platform support (Linux, Win*) http://www.globalsuntech.com/

Further Scenarios (1): 

Further Scenarios (1) Wireless Access Point (Hub Type) Wireless PC PCs Scenario 1: Wireless Access LAN WLAN

Further Scenarios (2): 

Ethernet Hub Wireless Access Point (Bridge Type) Wireless PCs Scenario 2: Wireless Bridging Further Scenarios (2) WLAN LAN

Further Scenarios (3): 

Further Scenarios (3) Wireless Access Point (Router Type) Scenario 3: Share Wireless AP Cable/DSL-Modem Internet WAN WLAN Wireless PCs

Further Scenarios (4): 

Cable/DSL- Wireless/ Wired Router Wireless PCs Scenario 4: Wireless/Wired Routing Further Scenarios (4) Cable/DSL-Modem Internet WAN LAN LAN WLAN

UMTS vs WLAN: 

UMTS vs WLAN

Slide141: 

Mobility and data rates mobility Data rate [Mbit/s] Source: http://www.netant.no Bluetooth 0,1 1 10 100 2G 3G – UMTS WLAN LAN Fixed Walk Vehicle UMTS: better mobility, connectivity WLAN: higher data rates, more cheap, but no telephone 0,4 2,0 5,5 65,5 WLAN UMTS (best support) TDSL ISDN in minutes, trailer , 30 MB Source: Focus, 34/2002

WLAN- Spectrum Allocation: 

5200 5600 5900 5700 5800 5500 5400 5300 5100 HIPERLAN HIPERLAN High Speed wireless access U-NII U-NII Frequency [MHz] License exempt. 455 MHz Sharing rules 100 MHz Unlicensed 300 MHz U-NII ... Unlicensed national information infrastructure source: www.ist-mind.org, www.3gpp.org WLAN- Spectrum Allocation

Slide143: 

Interworking UMTS/WLAN - User should be notified of any possible degradation - subscriber database could be shared, or separated in HLR/HSS (3GPP) or AAA (IETF) format Three classes: - no coupling - loose coupling - tight coupling UMTS/WLAN as completely independent Contra: Pro: - Rapid introduction - no impact on GSN nodes - poor handover - no common database, billing no coupling loose coupling tight coupling UMTS/WLAN use same database in AAA format AAA ... Authentication, authorization, accounting - poor handover - good handling - no impact on GSN nodes - improved handover performance - HIPERLAN/2 have to support complete UMTS interface - feasible if operator have both networks HIPERLAN/2 is connected through UTRAN to UMTS, using special interface

Data security in WLAN and UMTS: 

Data security in WLAN and UMTS Data security for WLAN: 802.11i new, additionally standards 802.11a/h and 802.11g complex solution for security packet encryption key distribution via RADIUS -Remote Access Dial-In User Service packet authentication partial compatibility with IPsec relevant against all attacks WPA - WiFi Protected Access preliminary to 802.11i properties similar to 802.11i competition to 802.11i  WEP - Wired Equivalent Privacy additionally to standard 802.11b, partially obsolete!!! users mobility between several Access- Points, without re-configuration (roaming) disadvantages: short key of 64 / 128 bit different, partially contradictory statements to offered security Data security for UMTS: IPsec Client/Server based, Clients and IPsec-Servers negotiate dynamic keys tolerant, relevant for key assignment to IP-subnets and against all Internet-attacks secrecy on the network layer: IP-datagrams TCP/UDP-segments ICMP/SNMP-messages Encryption via DES, 3DES and 40-bit-DES authentication via “IP Encapsulating Security Payload" (RFC 2406, 1998) “IP Authentication Header” (RFC 2402, 1998)

HomeRF (Radio Frequency): 

HomeRF (Radio Frequency) competitive standard to IEEE 802.11 Up to 128 network nodes Frequency jump in separations of 3MHz or 5MHz Low costs and support of synchronous services: DECT speech support 2,4 GHz (FHSS), transition power max. 100 mW, Shared Wireless Access Protocol (SWAP): hybrid protocol of DECT (TDMA) and CSMA according to IEEE802.11 (modified) up to 6 wireless fixed network connections however sinking market shares in comparison with IEEE 802.11

HomeRF: 

HomeRF data rate 1-2 Mbit/s 50 m reach within buildings Supplier: e.g. Intel with ANYPOINT (wireless home network) future: HomeRF + Bluetooth: DUAL MODE SYSTEM (Symbionics) ad-hoc possibly voice transmission - today only few manufactures

Wireless City Networking via 802.16: 

Wireless City Networking via 802.16 IEEE Wireless MAN/ ETSI Hiper MAN

Wireless City Networking: scenarios: 

Wireless City Networking: scenarios new IEEE 802.16 standards can provide great regions with fast Internet services Use fields: office materials shops cafes at the railway stations to surf at the parks

USA: Wireless MAN: 

USA: Wireless MAN Wireless MAN: 802.16-version in USA Backgrounds: competition to T-Mobile USA - mobile radio network provider great number of 802.11-Internet service providers (ISP via Wireless LAN) wide spread 802.11x – networks in the country via 802.11 provided approx. 2500 regions

Europa: Hiper MAN: 

Europa: Hiper MAN ETSI (European Telecommunications Standard Institute): activities in the range of 802.16 – development of Hiper MAN new marketable products: since July 2004 (according to announcement of Fujitsu Europe)

802.16 / 802.16a: 

802.16 / 802.16a Wireless MAN Standard 802.16 developed end of month January 2003 frequency bandwidth: 10 up to 66 GHz reach: up to 50 km (30 miles) data rate: up to 134 MBit/s new 802.16x standards can provide great regions with fast Internet service, momentary trial operation in Boston/USA (ISP via Wireless MAN) Start-Standard 802.16a frequency bandwidth: 2-11 GHz reach: up to 50 km (30 miles) data rate: up to 70 MBit/s only predominantly conceptualized for fast links of hotspots can be used to establishment of private DSL-links final operation inset: January 2005

802.16a-Forum: 

802.16a-Forum Members: Airspan Networks, Alvarion, Aperto Networks, Ensemble Communication, Fujitsu of America, Intel, Nokia, Proxim, Wi-LAN Aims: to provide compatibility of 802.16a-products among each other

Conclusion: 802.16 vs 802.11: 

Conclusion: 802.16 vs 802.11 802.11 advantage: in spite of sharp competition to Mobile Radio (IMT2000/UMTS) 802.11x gained the mass market well-elaborated 802.11x (x = a, b, c, d, e, f, g, h, i, WPA) disadvantage: existing bandwidth problems (at most up to 54 Mbit/s) reach at most up to 100m without directional antennas 802.16 advantage: covers approx. 50km (30 miles) substitution via 802.16 as access techniques possible in future cost-efficient in comparison to 802.11 disadvantage: averaged investment for leased circuits amounting to 1000$ per location necessary sharp competition to Mobile Radio (IMT2000/UMTS): to occupy the market is for Wireless Networks more important as for Mobile Radio! final operation inset: planned January 2005 only

Better than UMTS: future use scenarios of 802.16: 

(2) via Wireless MAN Access Point Wireless PCs Scenario: fast Internet Better than UMTS: future use scenarios of 802.16 (1) via ISDN, Modem, DSL Internet WAN Wireless MAN 802.16 WAN PC/LAN WWW-Server/ Intranet-Firewall up to 50 Km (30 miles) 70-134 Mbit/s ISP via Wireless MAN

Bluetooth: 

Bluetooth

Bluetooth - Facts: 

Bluetooth - Facts Harald Bluetooth was the King of Denmark in the 10th century 1998 started from Ericsson, Intel, IBM, Nokia, Toshiba Open Standard: IEEE 802.15.1 Generally for wireless Ad-hoc- piconets (Range < 10m) Goal: not expensive One-Chip-Decision for radio/ wireless communication networks Use fields: Connection of peripheral devices Support of Ad-Hoc-Nets Connection of different networks Frequency band in IMS-Range of 2,4 GHz

Bluetooth: 

Bluetooth Pico nets with up to 8 participants (ad-hoc) (one master, slaves) Scatter nets as an association of different pico nets frequency hopping is used for improving of interception safety and system robustness

Bluetooth - properties: 

Bluetooth - properties Range: - 10 cm up to 10 m at 1 mW transmitting power - up to 100m at 100mW Data rates: 433,9 kBit/s asynchronous-symmetrical 723,2 kBit/s / 57,6 kbit/s asynchronous-asymmetrical 64 kBit/s synchronous, voice service In future up to 20 Mbit/s (IEEE 802.15.3) Basic set-up Bluetooth 2,4-Ghz- HF Bluetooth- Baseband- Controller Host- System

Bluetooth-comparison: 

Bluetooth-comparison Source: http://www.okisemi.com

Bluetooth- functionality: 

Bluetooth- functionality Standby Inquiry after unknown Address Page after unknown Address Send data connected PARK HOLD SNIFF MAC-Address resigned MAC-Address available t =2 ms t =2 ms t =2 s t =0,6 s Not connected Standby connection- status active states Low-Power- states

Bluetooth – architecture (1): 

Bluetooth – architecture (1) Physical connection interface connection between end devices In hardware implemented ! connection between Hardware and upper protocol (only necessary, if L2CAP not implemented in Hardware!) Applications TCS,SDP,RFCOMM L2CAP LMP Baseband Radio Data Data HCL TCS …Telephony Control Protocol Specification SDP … Service discovery protocol RFCOMM … RF communication protocol (cable replacement protocol) LMP … Link Manager Protocol HCL … Host Controller L2CAP … Logical Link Control and Adaptation Protocol

Bluetooth- architecture (2): 

Bluetooth- architecture (2) Radio Layer - work area: ISM-Band (2,4 Ghz) - Spread Spectrum Communication - Frequency Hopping- Technology - high error rate acceptability through CVSD-encoding at heavy micro wave load Baseband - controls Radio- Layer 2 Modes: - Synchronous, connection-oriented transfer (SCO) voice connections need symmetrical, circuit-switched point-to-point-connections, Master reserves two successive time slots (up- and downstream) - Asynchronous, connectionless transfer (ACL) data transfers need symmetrical or asymmetrical, packet-switched point-to-point/multipoint- transfers, master uses polling CVSD… Continuously Variable Slop Delta (Sprachkodierung)

Bluetooth- architecture: 

Bluetooth- architecture Link Manager Protocol 3 Functions - Piconet management - link configuration - security functions Logical Link Control and Adaption Protocol Functions: - Mutiplexing (different applications can use connection between 2 devices simultaneously) - Reduzierung der Paketgröße der Anwendungen auf akzeptable Baseband- Paket- Größe - Quality of Service

Possible configurations: 

Possible configurations Master Slave Piconet Scatter net

Slide165: 

Bluetooth possible configurations association of different pico nets frequency hopping : jumps in k steps (k = 0…22 or 79) with Δf distances in ISM-band a) Peer to Peer (or 1 Master and 1 Slave) b) Multi-slave (up to 7 "slaves" with 1 Master) Scatternet Piconet Master Slave 4 Master Slave 3 Slave 1 Slave 2 Slave 5 Piconet 1 Piconet 2 Scatternet

Bluetooth - Frequencies: 

Bluetooth - Frequencies Source: http://www.mobileinfo.com - different frequencies around the world Goal: Harmonization of wavebands Δf… frequency distance between channels

Bluetooth - Framestructure: 

Bluetooth - Framestructure Single slot frame Multi slot frame source: http://www.intel.com one Slot Packet Frame fk fk+1 one Slot Packet Master Slave 625 µs one slot three slot Packets fk fk+1 Master Slave 3- Slot-packets 625 µs one slot Frame

Bluetooth – security : 

Bluetooth – security - 128 Bit Key encryption and authentication - every device has own 48 Bit- address - over 281 .1012 devices can keep apart - low range (manipulation only local!)

Bluetooth – security : 

Bluetooth – security Generic access: Three modes - non-secure - service level enforced security - link level enforced security For Devices: two modes - trusted - untrusted for Services: three modes: - services that require authorization and authentication - services that require authentication only - services that are open to all devices Bluetooth device initiates security procedures before the channel is established Sources: http://www.niksula.cs.hut.fi, Müller T., Bluetooth Security Architecture Bluetooth is not secure enough for critical transmissions (billing etc.)

Bluetooth – applications (1): 

Bluetooth – applications (1) replaces perhaps infrared in the area of the coupling of peripherals completely „Intelligent Shop“ shop informs the buyer about special offers by mobile phone or handles inquiries for offers in the individual halls Bluetooth-capable ticket machine Payment over mobile telephone is carried out without contacts control of home appliances by mobile telephone lower layers are developed further in the context of the IEEE 802.15 working group (WPAN - Wireless Personal Area Networks) higher data rates, further frequencies, but possible interferences with other systems

Bluetooth - applications: 

Bluetooth - applications wireless connection Headset Handy

HIPERLAN: 

HIPERLAN HIPERLAN/1 wireless LAN (as extension to conventional LANs) 5,15 - 5,25 GHz, ca. 20 Mbps, reach > 50 m, mobility < 10m/s decentralized Ad-hoc net, no QoS-guarantee HIPERLAN/2 wireless ATM-LAN (as extension to ATM and IP nets) 5,15 - 5,25 GHz, ca. 20 Mbps, reach 50 m, mobility<10m/s cellular structure with base stations, ATM service classes HIPERACCESS point-to-multipoint ATM connections 5,15 - 5,25 GHz, ca. 25 Mbps, reach 5000 m, stationary/quasi-stationary, point-to-multipoint, ATM service classes HIPERLINK point-to-point ATM connection 17,1 - 17,3 GHz, 155 MBit/s, reach 150 m, stationary/quasi-stationary, point-to-point, ATM source: ETSI RES 10, BRAN

Assessment of HIPERLAN: 

Assessment of HIPERLAN despite of some unique characteristics there are no products available yet, only single prototypes is planned as one of the alternatives for BRAN (Broadband Radio Access Network) in the Wireless ATM planned frequencies are originally not worldwide available (5,1-53GHz)

Wireless ATM: 

Requirements: wireless connection of mobile terminals to ATM-networks compatibility to existing standards existing networks should be easily upgradeable guaranteed service quality properties which other wireless nets don't offer UMTS and WLANs don‘t offer any data rates >50 Mbit/s Problems: ATM is conceived for high data rates ATM is optimized on reliable media applications should notice nothing of the wireless mode Wireless ATM

Wireless ATM: review: 

Wireless ATM: review WATM still is standardization endeavors, no definite standards approved the WATM forum has tried to standardize as much as possible, the WATM standard is relatively complex WATM supports relatively many configurations: wireless Ad-hoc networks wireless mobile end-devices: access to the network via radio subsystem, similar to access-points mobile end-devices: seamless handover between connected terminals mobile ATM-Switches (for planes, ships, trains etc.) fixed ATM-terminals: conventional ATM fixed terminals with radio access: comparable with line-of-sight radio links It is not arranged completely for which configuration also products will exist

Slide176: 

Satellite-based systems

Sample system: 

Sample system Inter-Satellite Link (ISL) Gateway Link (GWL) Mobile User Link (MUL) Spot beams Footprint Gateway Ground Station User PSTN, ISDN, GSM, ... Internet

Basics (1): 

Basics (1) satellites describe elliptical or circular orbit around the earth distance to the earth remains constant: - Appeal of the Earth - Centrifugal force - Mass of the satellite - Earth radius, 6.370km - Distance of the satellite to the Earth’s center - Grounding acceleration, g = 9,81 m/s2 - Angular frequency: - Cycle frequency of the satellite (1)

Basics (2): 

Basics (2) Formulae transformation: F = m . a (by Newton) Fgrav = k . M . m / r2 (Gravitation between 2 point masses) mg = k . M . m / R2 (Appeal on the Earth surface = Gravitation) k . M = gR2 FG = gR2 m/r2 = gm(R/r)2 (transformed) δt = 2 . (r-R) / c Signal propagation delay

Basics (3): 

Basics (3) (1) resolved to r gives: that means, the distance of a satellite to the earth's surface depends only on its cycle duration (special case T = 24h - > synchronous distance r=35.786 km) (2)

Satellite system classes: 

Satellite system classes

Geostationary Satellite systems: 

Base for Inmarsat Principle: Satellit Uplink Downlink Geostationary Satellite systems Constant position to the Earth, 3 satellites cover complete earth (with the exception of the polar caps), satellites move synchronously to the Earth Simple solution, however large distance (36000 km), therefore high signal propagation delay, long life time of the satellites: ~ 15 years low data rates, large transmission power required problems: on the other side of the 60th degree of latitude reception problems (elevation) because of a high transmission power unfavorable for mobile telephones signal propagation delay too high (0.25 s)

LEO- Systems: 

LEO- Systems non-stationary satellites (LEO - Low Earth Orbit) distance to the earth ~ 500 - 2000 km shorter signal runtimes (5-10 ms), lower transmission power of the mobile stations sufficing however more satellites necessary, frequent handover between satellites, approximately all 10 min. examples: Teledesic, Globalstar only low transmission power necessary, suitable for mobile phone networks Disadvantages: large number is necessary (50 - 200, or more) fast handovers within satellites are necessary short life time of the satellites because of atmospheric friction (5-8 years)

MEO- Systems: 

MEO- Systems ~ 10000km, lower number of satellites necessary : ~12 slow movement: handover between satellites is hardly necessary cycle duration: 6h high elevation enables coverage large, highly-populated areas Problems: signal propagation delay: 70 to 80 ms higher transmission power is necessary special antennas for small cells are necessary

Slide185: 

Service transitions in Inmarsat-C-service Fixed network Internet X.25 Net Email System modem PAD data + maps laptop fax data + maps Email desktop desktop desktop laptop Inmarsat - C – End-Terminal Graphic table Fax- Interface Mail Box text 600 bit/s 600 bit/s Inmarsat Satellite L-Band 1,5/1,6 GHz Rx/Tx (GPS)

Examples of satellite-based systems: 

Examples of satellite-based systems Globalstar can transfer bi-directionally up to 144 Kbit/s, through combination of channels Orbcomm - first commercial LEO–service worldwide http://Globalstar.com/

Comparison of satellite-based systems: 

Comparison of satellite-based systems

Slide188: 

Global Positioning System, GPS

Overview: 

Overview 24 satellites on the 6 orbits (20200 km, time of circulation = 12h) 5 earth stations (Hawaii, Ascension Island, Diego Garcia, Kwajalein, Colorado Springs) Accuracy: so called P-Code for military applications: on ~6m accurately, partially 2,8m so called Selective Availability Mode, SAM (artificial degradation) for civil applications: < 100m (1.5.2000 disestablished) Functionality principle: Triangulation GPS-receiver calculates distance to the satellite on the base of Time of Arrival of the received signals distances to at least three satellites enables the calculation of position, a fourth satellite can be used for determination of elevation over zero official initiation 1995, testing since 1978

Principle: TOA (Time of Arrival) / TDOA (Time Difference of Arrival): 

Principle: TOA (Time of Arrival) / TDOA (Time Difference of Arrival) Distance d, Signal Delay T Mobile Object synchronized clocks measurement of signal delay by speed of light between satellite and receiver, for instance T = 100 ms hence calculation of distance: d = T • c = 1 • 10-1s • 3 • 108 m/s = 3 • 107 m = 30.000 km calculation of spheres around each satellite the position is on the intersection point of three spheres

Principles: 

Principles satellites send a signal composed of three components 50 times per second: identification component: PRC (Pseudo Random Code), provides satellite recognition and status information position component: exact position of satellite time component: time point, when signal is transmitted the time offset measured by the receiver is corresponding to the Time of Arrival, from TOA the distance is calculated for measurement of TOA of signals very accurate clocks are required the exact position of the satellites must be known

Sources of errors: 

Sources of errors Clocks highly accurate atom clocks in the satellites simple clocks in the receivers are calibrated via measurement of a fourth satellite Satellite position satellite orbits are relatively stable and forecastable deviations are measured by US DoD deviations are transmitted as correction factor to the satellites using the PRC Miscellaneous error sources atmospheric faults multi-path propagation

Differential GPS, DGPS: 

Differential GPS, DGPS use of a stationary receiver as reference position of this receiver is exactly known the stationary receiver carries out position determination and calculates correction factor from the actually obtained position on the base of deviations correction factor is delivered to the mobile receiver

DGPS accuracy grades: 

DGPS accuracy grades Accuracy under 10cm: professional applications, for instance is interesting in meterology and respectively for user of well-engineered software decisions (machine control systems etc.) Accuracy under 1m: events mapping, control of machines, traffic control systems, agriculture Guaranteed accuracy under 10m: agriculture/ forestry, railway (wagon search service), car navigation (private/commercial)

Galileo: 

Galileo EU-Project for installation of European satellite navigation system initiation: prospective 2008 positioning accuracy: 45cm 30 satellites Approx. costs: 3,2 Billion €

Slide196: 

„ A system that both competes with and complements the American GPS system “ Galileo ITS (Intelligent Transport System) based on a constellation of 30 MEO-satellites ground stations providing information concerning the positioning of users in many sectors usable: transport (vehicle location, route searching, speed control, etc.) social services (e.g. aid for the disabled or elderly) the justice system ( border controls) public works (geographical information systems)

Slide197: 

Galileo -architecture Service centres GALILEO GLOBAL CONTENT MEO Constellation OSS Network TTC Navigation control & constellation management OSS Network ... User segment UHF- S&R I-Band- NAV Local Components Local MS Local MS . . Data link Data link UMTS External complementary systems Regional Components BSS network . . COSPAS-SARSAT ground segment BSS network RMS network GEO EGNOS i-band i-band Integrity determination &dissemination s-band s-band

Slide198: 

Broadcast Systems, Distribution Networks

Overview: 

Overview special variants of asymmetric communication systems HSCSD supports for instance asymmetric connections regarding to data rate, also ADSL WWW is the biggest representative of asymmetric communication: data volume of uplink (URLs) is much lower than downlink (complete HTML-pages) Problem of distribution systems: Sender can be optimized for a large quantity of receivers only, for instance videostreaming Examples: DVB, Digital Video Broadcast DAB, Digital Audio Broadcast

Principle of Distribution Systems: 

Principle of Distribution Systems Time information sequence is optimized for expected access behavior of all consumers t Individual access sample of diverse consumers can more or less deviate from expected access behavior

Digital Audio Broadcast, DAB: 

Digital Audio Broadcast, DAB Audio-transmission in CD-Quality Non-sensible towards interferences of multi-path-propagation Use of SFN (Single Frequency Network) – i.e. all senders of some broadcast-program are working on the same frequency as a rule Frequencies: UHF,VHF, for instance: 174-230 MHz, 1452-1492 MHz Modulation methods: DQPSK (Differential Quadrature Phase Shift Keying) Optionally COFDM (Coded Orthogonal Frequency Division Multiplexing) is used with several carrier frequencies inside some DAB-channel (its quantity is between 192 and 1536), 1,5MHz bandwidth for each channel FEC (Forward Error Correction)-mechanism for fault correction Up to 6 stereo-programs by 192 kbit/s in the same frequency band are transmittable alternatively data can be transmitted with up to 1,5 Mbit/s (responding to the used code rate etc.)

Digital Audio Broadcast, DAB: 

Digital Audio Broadcast, DAB 2 Transport Mechanisms Main Service Channel (MSC): Data, Audio, Multimedia 2 Transport Modes: Stream Mode, Packet Mode Fast Information Channel (FIC): Transport of Fast Information Blocks (FIB, 32 Byte) – control data for interpretation of Data in the MSC, can be also used for services such as Traffic Dispatches, Paging etc. Audio-converting: PCM 48 kHz & MPEG2-Audiocompression High transmission rates by high velocities, up to 250 km/h, responding to distance from sender and error security class, use for instance in high-speed train MOT (Multimedia Object Transfer) protocol for data transmission Cyclic repeat and caching of data blocks

Dynamic channel reconfiguration for DAB: 

Dynamic channel reconfiguration for DAB Ensemble-Configuration Temporarily changed Ensemble-Configuration

DVB - Digital Video Broadcasting: 

DVB - Digital Video Broadcasting 1991 ELR (European Launching Group) founded Goal: joint digital Television System for Europe Specifications: DVB-S, DVB-T, DVB-C Frequency reaches: 200, 550, 700 MHz Cell size: up to 60 km Used data rate: ~38,5 Mbit/s Velocity of mobile stations: up to 200 km/h Central Unit: combined DVB-Receiver-Decoder (set-top-box) can receive DVB-Data via satellites, B-ISDN, ADSL… some transmission systems offer a feedback channel for Video on Demand etc.

DVB - Digital Video Broadcasting: 

DVB - Digital Video Broadcasting Different Quality Levels defined: SDTV (Standard Definition TV) EDTV (Enhanced DTV) HDTV (High DTV) Data transport: User Data: MPEG2-Container (Data Transfer Unit) like DAB, Container doesn’t define the type of data Service Information about MPEG2-Container-content: NIT (Network Information Table): Information from a provider about offered services and optional data for the receiver SDT (Service Description Table): Description and parameters for each service in the MPEG2-stream EIT (Event Information Table): Data about actual transmission status TDT (Time and Date Table): e.g. updating of DVB-receiver

Possible contents of DVB/MPEG2-Container: 

MPEG2/DVB-Container MPEG2/DVB-Container MPEG2/DVB-Container MPEG2/DVB-Container HDTV EDTV SDTV Single channel (High Definition TV) Several channels (Enhanced DTV) Several channels (Standard TV) Multimedia (data broadcasting) Possible contents of DVB/MPEG2-Container

DVB used as medium for asymmetric Internet-access: 

DVB used as medium for asymmetric Internet-access Client sends data query to Provider, Provider transmits data to the satellite network, receiver obtains data via DVB-receiver Feedback channel can be phone network, for on-demand services Data rates: 6 up to 38 Mbit/s downlink, 33 kbit/s up to over 100 kbit/s (ADSL) uplink Advantages: data can be transmitted in parallel with TV no additional costs for satellite provider low priced for low-density populated areas Disadvantages: all users need satellite antennas only a minor part of the total bandwidth is usable not suitable for high-density populated areas

DVB as medium for the asymmetric Internet-access: 

Internet DVB–Card in the PC Satellite provider dedicated line (user-to-user) Service Provider Content Provider DVB as medium for the asymmetric Internet-access

3. Mobile Computing : 

3. Mobile Computing

Layer 3 Mobile IP v4 & v6 DHCP: 

Layer 3 Mobile IP v4 & v6 DHCP

Mobile IP (Internet Protocol): 

Mobile IP (Internet Protocol)

Problem situation: 

Problem situation computer mobility in heterogenic networks relocation between different IP-subnets Goal: transparent migration and localization, compatibility to IP, no changes of existing routers Idea: introduction of temporary/ actual IP-addresses (also “care-of-address”, COA); mapping of permanent to temporary IP-addresses using localization technique

Requirements to MobileIP according to IETF: 

Requirements to MobileIP according to IETF Transparency: mobile computer is permanently reachable via its previous “home-address” can change its network access point freely can also communicate after coupling/uncoupling Compatibility: supports each layer below IP (also 1 & 2) mobile computer can also communicate with each “non-mobileIP”-computer no changes to existing computer/routers Security: all registering messages must be authenticated

IETF Mobile IP Goals/Restrictions: 

IETF Mobile IP Goals/Restrictions Minimization of overheads: mobile connections are possibly wireless and have limited band width mobile connections have possibly higher error rate Efficiency and scalability: support of a large quantities of mobile computers support of a theoretically Internet-wide mobility

Architecture model : 

Global Internet Home Subnet Anywhere Foreign Subnet Home Agent (HA) Router Foreign Agent (FA) Correspondent Node (CN) Architecture model Mobile Node

Terms: 

Terms Mobile Node (MN) with permanent IP-address from Home Subnet Home Address permanent address of a mobile computer Home Agent (HA) with knowledge of actual residence of all MNs from so called Home Subnet, like GSM-HLR Care of Address temporary address of a mobile computer from Foreign Subnet Foreign Agent (FA) for assignment of temporary IP-addresses (care of address) and packet forwarding to MNs currently residing in its subnet

Log on via Foreign Agent: 

Log on via Foreign Agent Log on with a FA - Care-of Address (address of FA, is just an intermediate target for all MN- related packets, tunnel-end) or Application of a co-located Care-of Address (address from Foreign-Subnet, MN is tunnel-end itself), but reception of an Agent Advertisement Message with a set “R”-bit, i.e. the MN is forced to log on with FA itself, although it can operate autonomously MN HA Foreign Subnet Home Subnet 1.) Registration.request 2.) relaying request 4.) Registration reply FA 3.) relaying.reply {grant, deny}

Log on by Home Agent directly: 

Log on by Home Agent directly HA Home Subnet 1.) Registration.request 2.) Registration.reply {grant, deny} MN MN uses co-located Care-of Address MN is returned to Home Network and would like to log on/off itself with the HA Authentication: each mobile entity (MN, HA, FA) must be able to support a “mobility security association”, which is indicated via IP-address and SPI (Security Parameter Index). Mobile IP provides three different Authentication Extensions: Mobile - Home Authentication Ext. Mobile - Foreign Authentication Ext. Foreign - Home Authentication Ext.

Addressing: 

Addressing Problem: For the receivers 2 addresses are necessary (permanent and temporary IP-address respectively home address and COA) Methods of resolution: Encapsulation IP in IP, standard method in MobileIPv4 minimal Encapsulation IP-Option (not supported by all implementations)

IP in IP Encapsulation: 

IP in IP Encapsulation IP-source/target address of external/outer IP-Header defines the “end- points” of the tunnel IP-source/target address of internal IP-Header represents the actual packet sender respectively receiver Internal IP-Header isn't changed using “Encapsulator” (exception: TTL) IP HEADER IP PAYLOAD IP PAYLOAD IP HEADER OUTER IP HEADER

Routing (unicast): 

Routing (unicast) Mobile Node: in Home Network it operates like each other Node in Foreign Network it must search a Default Router using the following rules: FA COA: ICMP Router Advertisement-Part; IP-source address of Agent Advertisements (lower Prior.) co-located COA: ICMP Router Advertisement for this address Foreign Agent: FA must check by reception of tunneled packets whether internal target address corresponds with one of the IP-addresses of Visitor List FA must route the received packets of registered MN’s!

Routing (unicast) II: 

Routing (unicast) II Home Agent: HA must intercept each packet for absent MN in addition IP-target address of each incoming packets is verified if MN has no mobile coupling presently, the packets sent to it must not be intercepted, MN is situated in Home Subnet and accepts packets itself or is off-line

Routing (necessities): 

Routing (necessities) ARP (Address Resolution Protocol): oriented to resolution of IP-addresses in physical (Hardware, Link Layer) addresses (Ethernet: MAC-addresses of controllers) Proxy ARP: Proxy ARP-reply is an ARP-reply, which can be sent instead of a host A by other host B (with its hardware address) Hosts, receiving this reply, associate the hardware-address of node B with the IP-address of node A and send future packets for A to B Gratuitous ARP: is an ARP-reply, which is sent from a host, to force other hosts to update the records in their ARP-Caches this ARP-reply contains the IP-address, which should be changed in the ARP- Caches, as well as the hardware address which should be updated

Routing - Scenario: 

Routing - Scenario MN leaves Home Network MN decides to register FA Care-of Address Before Registration Request: MN re-sets a reaction on future ARP-requests Registration Request contains and accepts HA Request, implements Gratuitous ARP (IP-address MN ===> own hardware-address) and uses Proxy ARP to respond to ARP-requests corresponding to MN hardware address

Triangle Routing: 

Triangle Routing HA FA MN CN Foreign Network Home Network although CN is in the same Subnet like MN, packets are routed respectively tunneled via FA and primarily HA (possibly over half of terrestrial globe)!!! CN ===> MN: MN ===> CN: Be routed conventionally via Default Router Special case: Routing (MN & CN are in the same Subnet) Relief (IPv4): Route Optimization

Optimizations: Routing: 

Optimizations: Routing Terms: Binding Cache: table with Mobility Bindings of MNs (on CN, can tunnel itself now) Binding Update: message, contains up-to-date Mobility Binding of a MN, particularly the Care-of Address Procedure: Update of Binding Caches Control seamless Handoffs between FA‘s

Updating of Binding Caches: 

Updating of Binding Caches Binding Cache of a CN: Care-of Address of one/several MN‘s, with respective Lifetime No Entry: non-optimal Routing, BUT: HA doesn’t only tunnel a datagram from CN, but also sends a Binding Update to it CN should generate/change Binding Cache-Entry only then, when trusted Mobility Binding received (Bind. Upd.) for corresponding MN (ergo: Secure CN <===> HA) If FA receives tunneled Packet for a MN that is no longer in Visitor List, then it must care that corresponding CN receives a Binding Update (Binding Warning to HA)

Smooth Handoff between FAs: 

Smooth Handoff between FAs Problem of Basis-MobileIP: MN is with a new FA, but the packets tunneled to old FA will be lost FA Smooth Handoff: MNs are informed via new FA (packet can be forwarded) also Packets of hosts with non-up-to-date entries in Binding Cache can be forwarded now from old FA to the new FAs Previous Foreign Agent Notification Extension enables to prompt the new FA to inform the old FA (Binding Update Message)

MobileIP v4 & v6 in comparison: 

MobileIP v4 & v6 in comparison Mobile IPv4 Mobile IPv6 Optimal Routing, only if MN in the Home Network. (Otherwise non-efficient „Triangle“-Routing) Optimal Routing is generally possible, if CN knows the Care-of Address Routing HA is a possible bottleneck, because all traffic to the MN is processed over it HA is load essentially reduced, because CN‘s can just directly communicate with mit MN‘s Bottle neck Authentication is prescribed only by Registration and then also between HA and MN only Authentication and encryption are possible anywhere, because they are supported from IPv6 Security Used FA‘s / HA‘s must not be off-line Short-time failure/re-configuration of HA is mastered thanks to Automatic Home Agent Discovery. IPv6 is essentially simpler to upgrade, therewith also Mobile IPv6 Robustness No good performance due to IPv4-requirements and non-optimal Routing Essentially better due to requirements from IPv6 (uniform Headers, less Over- heads) and optimal Routing Performance

Assessment: 

Assessment Mobile IP enables the unlimited accessibility/roaming of mobile computers using perpetuation of their addresses and step-less transfer between subnets Particularly necessary for applications without “pull”-semantics (for instance, distributed applications with mobile users, videoconferences, VoIP) Keeping of permanent addresses are also important corresponding to Firewalls etc. in the case of call semantics Successive availability in the form of products

Dynamic Host Configuration Protocol (DHCP): 

Dynamic Host Configuration Protocol (DHCP) Properties: permits automatic configuration (IP-address, subnet-mask, router, DNS-Server, ...) and therewith integration of (mobile) computers Client/Server-Model Lease Concept Relevant for management of Care-of-Addresses

DHCP Assessment: 

DHCP Assessment no secure mechanisms standardized no standardized communication (signalization, for instance information exchange about managed address areas) between DHCP-servers good base for allocation of co-located COAs in MobileIP

IPsec: Network security: 

IPsec: Network security

IPsec: Security on the network layer (1): 

IPsec: Security on the network layer (1) IPsec - IP Security Protocol – new developed protocol from TCP/IP-Stack, related to the IPng - Group IPsec uses: encryption services -> DES, TripleDES and 40-bit-DES between hosts at a VPN (virtual private network) specification for Internet Key Management Protocol (IKMP), based on ISAKMP/Oakley (1998, Internet Security Association and Key Management Protocol - ISAKMP) IPSec-tunnels – encapsulation of TCP/IP-data via the ESP/AH- headers: Developed by S.Kent, R. Atkinson „IP Encapsulating Security Payload" (RFC 2406, 1998) and "IP Authentication Header" (RFC 2402, 1998) relevant for key assignment to IP-subnets

IPsec: Security on the network layer (2): 

IPsec: Security on the network layer (2) Secrecy on the network layer: a sending host encrypts/authenticates data encapsulated in the IP-datagrams TCP/UDP-segments ICMP/SNMP-messages Authentication on the network layer: target host can authenticate source IP-addresses Basic protocols: Authentication Header (AH) Protocol Encapsulation Security Payload (ESP) Protocol AH and ESP both requires target and source Handshake-Routine: establishment of a logical channel via network layer, called Service Agreement (SA) each SA is unidirectional Distinctly determined via: security protocol (AH / ESP) source IP-address Con-ID of 32 Bit

Encapsulation Security Payload (ESP) Protocol: 

Encapsulation Security Payload (ESP) Protocol offers secrecy, host authentication and data integrity data, ESP trailers encrypted next header field is a trailer in the ESP ESP- authentication field is similar to AH- authentication field; protocol field = 50

Authentication Header (AH) Protocol: 

Authentication Header (AH) Protocol offers host authentication and data integrity, but no secrecy AH headers inserted between IP-Header and IP-data field; protocol field = 51 participated routers process datagrams as usually AH-Header consists of: Con-ID authentication data: signed message digest calculated via original IP-Datagram, offers authentication of source hosts and data integrity next header field is specific data type (TCP, UDP, ICMP etc.)

Slide238: 

Layer 4

Problems of conventional protocols: 

Problems of conventional protocols Problem: Loss of packets on the radio channels with higher bit-error rate (BER) results in frequent retransmissions of packets and therewith in further efficiency loss TCP-Protocol uses so called “Slow-Start”-mechanisms: window size is reduced by significant packet losses; this is reasonable for fixed networks, to react on overload, but not for packet losses due to higher BER limited suitability of conventional transport protocols for mobile communication!

Conventional protocols: 

Conventional protocols Congestion Control: packet loss as a rule, in fixed networks occurs only by overload of several components reducing of transmission rate Slow Start: sender calculates a traffic window size start with window size 1 exponential growth till to Congestion Threshold then linear growth Fast Retransmit / Fast Recovery: If ≥ 3 DUPACK (duplicate ACK) are received -> sender informs about packet losses and repeats missing packets

Resulting problems in mobile environment: 

Resulting problems in mobile environment packet losses due to transmission errors are wrongly interpreted as traffic jam (Congestion)! > Slow Start is also wrong > Ideally the packets lost due to transmission errors are simply repeated (no effects on Congestion Control) great variances of Round-Trip-Time

Scenario: 

Scenario Mobile Host Fixed Host Access Point 1 Access Point 2

Solutions: 

Solutions Sender- transparent: to hide the packet losses transparent to the sender transmission repeat via Access Point on layer 2 on TCP-layer Wireless-aware sender: sender understands the reason of packet loss explicit notification of senders sender tries to determine the reason of loss Where will be the modifications carried out?: only by the sender only by the receiver only on the transient node (Access Point) combinations

Slide244: 

Separation between transport functionality in the fixed network respectively in the mobile network: MobileTCP is specially optimized (up to 100% of efficiency improvement possible) system-internal TCP-Handovers are necessary, however transparent for fixed computer (Workstation) Work- station MSR MSR Mobile node Mobile Support Router TCP Fixed network Mobile TCP Mobile network TCP-Handover by relocation of mobile node Solution “Split Connection“

Example of I-TCP (indirect TCP): 

Example of I-TCP (indirect TCP) separation of TCP-connection at the Access Point optimized TCP over the wireless Link (not absolutely necessary) no changes of TCP for the fixed network transparent for Fixed Host loss of End-to-End-semantics Mobile Host Fixed Host Access Point 1 „wireless TCP“ „standard TCP“

Example of I-TCP: 

Example of I-TCP Mobility: status and buffer transfer Mobile Host Fixed Host Access Point 1 Access Point 2

I-TCP Assessment: 

I-TCP Assessment no changes in the fixed network the errors in the wireless part aren’t propagated to the fixed network both parts can be optimized independently relatively simple: „wireless TCP“ concerns one Hop only the properties of wireless networks (bit-error rate, delay time) are known, therefore fast retransmissions are possible loss of End-to-End-semantics additional costs (computation time, storage place) concerning the Access Point high delay times with handover caused by buffering of data by Access Point IT-security mechanisms must be adapted

Example of Snoop: 

Example of Snoop transparent extension of Access Point from sender’s viewpoint Access Point listens to the traffic (snoops) and filters the ACKs buffering of data, are sent to the mobile computer after losses of packets in the wireless network a direct retransmission takes place between Access Point and Mobile Host Access Points send NACK after packet losses of MH Mobile Host Fixed Host Access Point 1 TCP Buffer „local retransmission”

Snoop Assessment: 

Snoop Assessment maintenance of End-to-End-semantics modifications only at the TCP-Stack of Access Points errors in the wireless part can be corrected locally Soft State no status transfer at new Access Point is necessary change is possible, also if the new Access Point possesses no Snoop no complete transparency of wireless connection handling of NACK requires the modifications of MH IT-security: encryption can prevent an access to TCP-Header (most of the up-to-date approaches use End-to-End-encryption!)

Slide250: 

Higher Layers and Services

Wireless Application Protocol - WAP: 

Wireless Application Protocol - WAP Based partially on the materials of WAP-Forum

WAP – Standard Overview: 

WAP – Standard Overview Goal: Fusion of Internet-Technologies and mobile radio, creation of new innovative services standardized by WAP-Forum (http://www.wapforum.org), initiated by Ericsson, Nokia, Motorola specifies application environment and protocols for mobile end-devices such as radio phones, PDAs, pagers

Why WAP?: 

Why WAP? Mobile radio networks and mobile phones possess special properties and requirements Display: sizes and presented colors, numerical keyboard, lower processor performance and storage capacity ... Networks: low data rates, high delays and costs WAP offers the use of several carriers TCP/IP, UDP/IP, USSD, SMS, ... USSD - unstructured supplementary service data (GSM) SMS - short message service (GSM)

Why WAP ?: 

Why WAP ? WAP-architecture has a modular organization the modules build together a complete Internet-protocol-stack WML-contents can be queried by HTTP-request-messages WAP uses XML (eXtensible Markup Language)-Standard as well as optimized contents and protocols user interface of conventional end-devices is supported by WML-components enhances acceptance by users WAP uses conventional HTTP-Servers existing development strategies are applicable in the future (common gateway interface - CGI, active server pages - ASP, netscape server API - NSAPI...)

Why HTTP/HTML doesn’t suffice?: 

Why HTTP/HTML doesn’t suffice? Big pipe - small pipe syndrome

Slide256: 

WAP-overview WAP-standard defines: Environment = Wireless Application Environment (WAE) WML (Wireless Markup Language) micro-browser WMLScript virtual machine WMLScript standard library Wireless Telephony Application (WTA) Interface Contents = WAP Content Types Layer architecture Wireless Session Protocol (WSP) Wireless Transaction Protocol (WTP) Wireless Datagram Protocol (WDP) Interface definitions for mobile network

Comparison: Internet/WWW and WAP: 

Comparison: Internet/WWW and WAP HTML JavaScript HTTP TCP/IP UDP/IP Wireless Application Environment (WAE) Session Layer (WSP) Transport Layer (WDP) other services and applications Internet Wireless Application Protocol SMS - Short Message Service (GSM), GPRS - General Packet Radio Service (GSM II+), CDMA - Code Division Multiple Access, CDPD - Cellular Digital Packet Data

Wireless Application Environment - WAE: 

Wireless Application Environment - WAE environment for distributed applications with specific reference to low-performance end-devices with limited operation comfort and mobile radio networks Goals: network-independent application environment optimized for application in mobile radio systems Internet, i.e. WWW–programming model high interoperability level

WAE – abstract network architecture: 

WAE – abstract network architecture Network Application WSP/HTTP Request {URL} WSP/HTTP Reply {Content}

Constituents: 

Constituents Architecture Programming model Browser, Gateway, Content Server WML as page markup language WMLScript as scripting language WTA offers access to phone services Content formats sets free-defined formats: bitmaps, phonebook records, dates ...

Options: 

Options User Agent Profiling to user, end-device, ... adapted contents Push-model network initiates delivery of contents Options for performance improvement Caching, ...

Sample: WAP-Gateway: 

Sample: WAP-Gateway WAP Gateway HTTP WSP/WTP

Sample: WAP - Application Server: 

Sample: WAP - Application Server Contents WML Decks, WML-Script WAP Application Server WSP/WTP

Wireless Markup Language - WML(1): 

Wireless Markup Language - WML(1) HDML - Handheld Device Markup Language, W3C - World Wide Web Consortium, XML - eXtensible Markup Language HTML-like page markup language different font styles are available, tables and graphics too, but limited based on W3C-XML uses HTML and HDML-elements Deck/Card-metaphor interactions-/selection possibilities are separated in Cards navigation (anchor: #) takes place between Cards Deck-stack corresponds to a WML-file

Wireless Markup Language - WML(2): 

Wireless Markup Language - WML(2) explicit navigation model between Decks Hyperlinks Events from user interface History variables and status-management variable status can tell about validity of a stack

WML– text styles: 

WML– text styles <wml> <card id=“Card1” title=“Text Styles”> <p align="left"> <i>italic</i>, <b>bold</b>,<br> <big>big</big>, <small>small</small>, <u>underlined</u> </p> </card> </wml>

WML-example (1): 

WML-example (1) <wml> <card id=„Card1" title=„Currency" newcontext="true"> <p> Amount: <input format="*N" name=„amount" title=„Amount:"/> From: <select name=“from“ value=" USD“ title=„From:"> <option value="EUR">Euro</option> ... <option value="USD">US Dollar</option> </select> To: <select name= ... <br/> = <u>$(conv)</u> <do type="accept" label=„Calculate"> <go href=“bsp.wmls#convert('conv', '$(from)','$(to)',$(amount))"/> </do> <do type="help" label="Help"> <go href="#card1_help"/> </do> </p> </card> ...

WML-example (1): Processing: 

WML-example (1): Processing

WML-example (2): 

WML-example (2) <card id="card1_help" title="Help"> <onevent type="onenterforward"> <go href="bsp.wmls#getInfoDate('date')"/> </onevent> <p> Currency exchange rates stem from Federal Reserve Bank of New York and are from $(date). <do type="prev" label=„Back"> <prev/> </do> </p> </card> </wml>

WMLScript-overview (1): 

WMLScript-overview (1) scripting language, similar to JavaScript procedures, loops, conditions, ... optimized for devices with low storage capacity and CPU-performance integrated with WML, enables: reducing of network workload validation of inputs access to vendor-specific APIs programming of conditional logic

WMLScript-overview (2): 

WMLScript-overview (2) Bytecode-based Virtual Machine stack-oriented design ROM-able designed with regard to simple, less work-expensive implementation Compiler in network better utilization of network capacity and end-device storage Standard library basic functionality for processing of strings, URLs, ...

WMLScript-example: 

WMLScript-example extern function getInfoDate(varName) { WMLBrowser.setVar(varName,„June,3,2002"); WMLBrowser.refresh(); } extern function convert(varName,from,to,amount) { var multiplier = 0.0; ... if (from == „EUR") { ... if (to == „EUR") multiplier = 1.0; else if (to == „RUR") multiplier = EUR_RUR; ... } else if ... WMLBrowser.setVar(varName,returnString); WMLBrowser.refresh(); }

Wireless Telephony Application - WTA (1): 

Wireless Telephony Application - WTA (1) offers mechanisms for applications in field of telephony primary focus: operators/providers and vendors security and trust are the emphasis WTA Browser using improvements of standard WML/WMLScript- browsers own interface WTAI (... Interface)

Wireless Telephony Application - WTA (2): 

Wireless Telephony Application - WTA (2) WTAI contains: call control, messaging, interface to phonebook, events processing... own Client/Server-interaction model event signalization... security via separation browser and port separated WTAI in WML and WMLScript available

WAE content formats: 

WAE content formats WAE defines uniform formats visit cards, so called IMC vCard Standard dates, IMC vCalendar Standard graphics, WBMP (Wireless BitMaP) compiled WML, WMLScript Goal: Interoperability IMC - Internet Mail Consortium

WAP layer architecture: 

WAP layer architecture Wireless Datagram Protocol (WDP) Carrier Service A Carrier Service B Carrier Service C Carrier D Service D Physical Layer Air Link Technology Carrier A Adaptation Carrier B Adaptation Carrier C Adaptation Wireless Transport Layer Security (WTLS)

Wireless Session Protocol: 

Wireless Session Protocol supports Client/Server context (shared state), optimization of content transmission offers semantics and mechanisms, which are based on HTTP and improvements for use in mobile radio networks with low-performance end-devices

WSP overview (1) : 

WSP overview (1) HTTP elements: extensible request/reply methods extensible request/reply headers uniform contents composed objects asynchronous requests Improvements: binary encoding of headers session headers (Client & Server) confirmed and unconfirmed network-initiated delivery (Push)

WSP overview (2) : 

WSP overview (2) Improvements corresponding to HTTP: negotiations of supported characteristics session suspend/resume multiple complete asynchronous transactions connectionless service Why doesn’t HTTP suffice? no compact encoding insufficient negotiations Push doesn't exist

Characteristics: 

Characteristics message size protocol options Confirmed Push Facility/ Push Facility (unconfirmed) Session Resume … maximum outstanding (unanswered) requests Header Code Pages (known field names in the protocol headers are separated into pages) ...

Suspend/Resume: 

Suspend/Resume Server knows, when a Client accepts data (Push) multi-carrier devices dynamical addressing enables release of carrier resources

Wireless Transaction Protocol (WTP): 

Wireless Transaction Protocol (WTP) Goal: efficient request/reply-based transport mechanism for mobile radio networks and low-performance end-devices Properties: robust data transmission no explicit connection set up and connection release data are transmitted already with the first packet packet oriented abortion-function for outstanding (unanswered) requests

Wireless Transaction Protocol (WTP): 

Wireless Transaction Protocol (WTP) Properties: supports concatenation of messages further WTP features: repeated transmission due to packet loss (selective) fragmentation port numbers (UDP) flow control Transaction = Interaction between Initiator and Responder

WTP – transaction classes (1): 

WTP – transaction classes (1) Class 0: non-robust datagram-service for instance for Push during a session shouldn’t substitute WDP the transactions are closed after transmission of Invoke Class 1: robust datagram-service the transactions are closed after transmission of Invoke

WTP – transaction classes (2): 

WTP – transaction classes (2) Class 2: robust datagram-service with robust Invoke- and robust Result-messages the transactions are closed via the Initiator after answer confirmation of the Responder

Wireless Datagram Protocol (WDP) : 

Wireless Datagram Protocol (WDP) provides connectionless, non-robust datagram-service is substituted by UDP, if IP the a carrier re-adaptation to the carrier takes place in the Adaptation Layer supports port numbers

Wireless Transport Layer Security (WTLS): 

Wireless Transport Layer Security (WTLS) enables secure connections, uses protocol elements of known, secure Internet-protocols (TLS) provides mechanisms for encryption, strong authentication, integrity and key management corresponds to guidelines of national authorities offers end-to-end security

WAP & Security: 

WAP & Security WTLS (Wireless Transport Layer Security) offers only security via encryption of transmitted data (Grade #1) presently, similar to TLS, only communication trustiness is protected Grade #2 supports Server- and Client-certificates, for instance via additional chip-cards in mobile phones, so called WIM - Wireless Identification Module

WAP & Security: 

UBS (Switzerland) data with WTLS class 2, 128 bit 3DES encrypted UBS authentication against mobile phone via certificates with a key size of 1024 bit participant authentication against UBS via WAP similarly like via Internet with agreement number, password and list-number automatic connection release (Timeout) embedded after ten minutes without interaction participant is demanded to re-authenticate with password und list-number input Deutsche Bank (Germany) WTLS (Wireless Transport Layer Security) end-to-end-encryption data encryption already at the mobile phone decryption at the server WAP & Security Sources: UBC.ch,db24.de

WAP-example: access to enterprise data: 

WAP-Gateway Web-Server Java-Servlet-API WML HTTP Dir-X-wap Dir-X-Servlet LDAP-Client Server LDAP/X.500-Directory-Service LDAP Server WML- pages Profiles WAP-example: access to enterprise data

Slide291: 

WAP-example: access to enterprise data Example: Siemens Dir-X Meta-Directory Service as a base of a corporate information pool software-package consists of Directory Server (Dir-X-Metahub) and several Clients, is completely LDAP v3 compatible, based on X.500 2 Gateways outwards: Dir-X-Web and Dir-X-wap secure access also via WAP available, because all security properties of Directory-Servers are handed-on to mobile user registration via phone number and password, the authorizations/licenses are deposited within the system in user profiles Java-Servlets built the kernel components of WAP-connection Dir-X-wap-Server: Servlet-components undertake communication with the Web-Server LDAP-Client provides data exchange between the Dir-X-wap-Server and the directory service

Slide292: 

WAP-example: access to enterprise data Dir-X-Wap-Application: consists of a set of WML-pages containing DSL Dir-X-Servlet parses DSL-commands 2 configuration files for an application necessary: Global Profile: contains information for the Servlet Application Profile: stores the data that are necessary to execution of WAP-application In principle, each Web-Server is usable with the product, it must only support the Servlets DSL: Directory Script Language; Language for processing of directory requests from Web- or WML-pages and for representation of obtained results in WML or HTML, contains the language elements for LDAP-access

WAP-examples: 

WAP-examples Bond/Security-Order processing: Consors, Advance Bank, Deutsche Bank Mobile “Yellow Pages” – Orange Telecom Mobile Timetable: wap.hafas.de Mobile Auctioning: wap.yahoo.de, wap.ebay.de Mobile „Last Minute Bargain “: 12snap at Vodafone, presently also with WAP Mobile marketplaces/stock exchanges (Mobile Brokerage): http://www.heizoelboerse.de/ http://www.amazon.de/

WAP-example: Bond/Security-Order: 

Bond/Security-Order Mobile Banking Mobile Brokerage WAP-example: Bond/Security-Order

WAP-example: Bond/Security-Order: 

Private Banking-> Login page Other services ... Lufthansa, Sixt, etc. WAP-example: Bond/Security-Order

WAP-example: Bond/Security-Order: 

WAP-example: Bond/Security-Order Main menu Brokerage ... Bond/security info

WAP-example: Bond/Security-Order: 

WAP-example: Bond/Security-Order Order book Status of bond transactions Executed and deleted orders are indicated in the order book for some days more Partial execution of some order is presented as one open and one executed partial order in the order book Details to an order could be indicated via dial-up of correspondent Links

WAP-example: Bond/Security-Order: 

Portfolio review Bond/security depots WAP-example: Bond/Security-Order

WAP-example: Bond/Security-Order: 

WAP-example: Bond/Security-Order Brief queries exchange rates of Bonds/Securities with a delay of approx. 15Min search criteria Bond/Security-ID and/or Bond/Security-name

WAP-example: soccer/football score: 

WAP-example: soccer/football score source: http://www.wapgoal.com

Further WAP-examples: 

Further WAP-examples soccer/football scores: http://wap.goal.com auctioning: http://wap.12snap.com miscellaneous: http://wap.yahoo.com

WAP-example: timetable service: 

Input the address ...wait ... WAP-example: timetable service Input -> English -> Query... …wait ...

WAP-example: timetable service: 

Input the start & target railway stations ...Dresden, …Hannover ...scroll … WAP-example: timetable service Input ..date, time.... …scroll …

Slide304: 

After input … search... ..wait.. WAP-example: timetable service Selection of train connections with departure platform ...earlier/later... then probably -> END

For comparison: PC-timetable service: 

For comparison: PC-timetable service PC-timetable service is still detailed!

WAP-result: 

WAP-result WML doesn’t bring whole Internet’s diversity to a mobile phone there are no satisfactory rate models at the moment; the data-rates are too low even with GPRS limited input and selection possibilities require a reconsidering of interaction semantics, WAP isn’t oriented for many applications, for instance catalogs with a large selection -> PDAs, appliances, voice input and -recognition with introduction of data services with higher data-rates WAP could lose its relevance possibly -> XHTML however WAP means a first step towards independence from PC by access to Internet contents -> multi-dimensional distribution channels for information WAP means the start for creation of a formidable user population (potentially all mobile radio participants)!

WAP-Improvements: WAP2.0 (1): 

WAP-Improvements: WAP2.0 (1) New version Internet-based data services on mobile phones approved by WAP Forum mid-2001 oriented to GPRS and 3G cellular/UMTS Useful services at WAP2.0 devices color graphics and Pictograms location-specific content, navigational functions and user-friendly menus animation representations and streaming media Multimedia Messaging Service (MMS) large-file downloading (music) synchronization of user information with personal information manager software on a desktop PC in a remote location Source: http://www.wapforum.org

WAP-Improvements: WAP2.0 (2): 

WAP-Improvements: WAP2.0 (2) WAP 2.0 builds upon the latest Internet standards: XHTML, TCP/IP, HyperText Transfer Protocol (HTTP/1.1) and Transport Layer Security (TLS) uses mostly TCP as transport optimized for small low-performance end-devices WAP 2.0 supports additionally: Wireless Telephony Application (WTA), Push, and User Agent Profile (UAPROF) utilize more advanced features in WAP 2.0 than in WAP1.x

WAP-Improvements: WAP2.0 (3): 

WAP-Improvements: WAP2.0 (3) Application development easier development of WAP applications More comfortable user environment Migration aspects WAP2.0 offers a migration to XHTML (Extensible Hypertext Markup Language) and TCP (Transmission Control Protocol) Supporting XHTML, WAP 2.0 reduces development costs, allowing developers to write applications for both PC and WAP Security offers more secure due to “end-to-end encryption” (from the mobile device to the server)

WAP2.0 and i-mode: 

WAP2.0 and i-mode Competition & Fusion NTT DoCoMo's I-Mode is a serious competitor of WAP2.0 NTT DoCoMo's I-Mode moves in the direction of support of XHTML and TCP, too I-mode and WAP2.0 will probably converge

i-Mode An overview: 

Based partially on the materials of NTT-DoCoMo i-Mode An overview

Structure: 

Structure

Overview: 

Overview i-Mode is a product and a trademark of NTT-DoCoMo The enterprise NTT-DoCoMo started in February 1999 with a proprietary development: i-Mode, although NTT-DoCoMo is the member of WAP-Forum itself Meantime i-Mode has got a large number of registered users : over 33 millions Source: http://www.nttdocomo.com

Properties: 

Properties i-Mode is packet oriented always online, no time delays to dial-up billing regarding data volumes and not regarding to time simple page markup language – compact HTML (cHTML) End of 2002: change into XHTML (WAP 2.0) a great success in Japan, because private computers and private Internet access over fixed networks are infrequent In Germany E-plus has started i-Mode on 16th march 2002

compact HTML: 

compact HTML cHTML or compact HTML is a language subset of HTML very simplified HTML Lists, Forms, Selections, Input fields are possible no Frames, no Tables, no CSS 166 additional pictograms, for instance Fine Motor sports WC Heartbreak

Slide316: 

compact HTML (2) Access key-Attribute for direct link activation respectively for direct selection of input fields pictures can be displayed only in GIF-format, max. 5 KB per page. GIF-pictures mustn’t larger than 120*128 dots (little display) also animated GIFs 256 colours (capable of Display) Compact HTML Sites look like “normal” HTML, so also “normal” Browsers like Netscape can work with them an i-Mode screenshot i-Mode – on a mobile phone

Network Configuration: 

Network Configuration

i-Mode network architecture: 

PDC: Personal Digital Cellular Telecommunication System PDC-P: PDC Packet System BS: Base Station IP: Information Provider M-PGW: Mobile Message-Packet Gateway Module MS: Mobile Station M-SCP: Mobile-Service Control Point NSP: Network Service Provider PGW: Packet Gateway Module PPM: Packet Processing Module i-Mode network architecture http://www.nttdocomo.co.jp/ i-mode Server PDC-P Network

i-Mode network architecture (2): 

i-Mode network architecture (2) i-Mode Server: - consists of multiple server systems (B-,C-,M-Max ..), each server system is responsible for special tasks - represents the contents of „Information Providers“, operates Internet-Mail and i-Mode-Mail, enables the connection to Internet M-PGW (Mobile Message-Packet Gateway Module): transforms the protocols: TCP with i-Mode-Server and TLP (Transport Layer Protocol) with PPM PPM (Packet Processing Module): executes the packet connection with the mobile end-devices/peripherals

i-Mode network architecture (3): 

i-Mode network architecture (3) M-SCP (Mobile-Service Control Point): authentication of user data (similar to voice communication) PGW (Packet Gateway Module): transition to other networks, for instance to offer the enterprises a Virtual Private Network (VPN)

i-Mode protocol stack: 

i-Mode protocol stack TLP: Transfer Layer Protocol CC: Call Control MM: Mobility Management RT: Radio Frequency Transmission Management LAPDM: Link Access Protocol on the D-Channel, modified PMAP: Packet Mobile Application Part HTTP: HyperText Transport Protocol SMTP: Simple Mail Transport Protocol UITP: User Information Transfer Protocol NWMP: Network Management Protocol TCP/IP: Transmission Control Protocol/ Internet Protocol L1: Layer1 (Physical Layer Protocol) L2: Layer2 (Data Link Layer Protocol)

i-Mode protocol stack II: 

i-Mode protocol stack II UITP (User Information Transfer Protocol): transmits user information such as, for instance, MSN (Mobile Subscriber Number) to i-Mode-Server NWMP (Network Management Protocol): performs i-Mode Service-functions TLP (Transfer Layer Protocol): has a simplified transmission procedure and can transmit the signalization and user data together

Java for mobile phones: 

Java for mobile phones base: Java 2 micro edition and Java MIDP (Mobile Information Device Profile) downloading of Java-programs (ca. 30-50 kByte); color representation; applications, also games etc. billing via micro-payment of operator (ca. 1-5 € per application) products e.g. of Nokia, Ericsson, Siemens; support through big operators

M-Commerce - applications: 

M-Commerce - applications Mobile Shopping Mobile Banking Mobile Brokerage Mobile Traveling

Pervasive Computing: 

Pervasive Computing Operation as parallel as possible of all users independent of the terminal, it means terminals with different equipment (PC‘s, mobile phones, PDAs, Applicances, etc.) should be supported by most different entrance nets It means finding a suitable system architecture for “multidimensional“ Internet communication (e.g. regarding end terminals) over *ML (Markup Languages)

System architecture, one-dimensional: 

System architecture, one-dimensional WWW-Browser Web Server databases, etc. Application Server Thin Clients Firewall Firewall

System architecture, one-dimensional: 

System architecture, one-dimensional

Properties of application servers: 

Properties of application servers main characteristics: object-oriented communication systems component- framework transaction concepts security concepts connection of legacy applications integration of WWW-services general support of design, deployment and runtime

System architecture, two- dimensional: 

System architecture, two- dimensional WAP Server WWW-Browser Web Server Data bases, etc. Application Server Thin Clients WAP-Browser Firewall Firewall …e.g.: BEA WebLogic M-Commerce Solution

System architecture, two- dimensional: 

Application Server + WWW Server System architecture, two- dimensional standardize access to Backend, create business logic call data from the EJBs and generate e.g. XML convert XML into HTML, WML WAP-Server

XML (Extensible Markup Language): 

design principles use in the Internet more powerful than HTML separation of content and style possibility of definition of user-specific document-types ability of XML-document processing XML (Extensible Markup Language)

XML- document „bibliography“: 

special tags reference to Style Sheet File XML- document „bibliography“

Slide333: 

XML-Documents can have a DTD (Document Type Definition). The DTD can be contained in the document or can be referenced by a link. A DTD specifies, which tags are permitted and how these can be combined. It has a special meaning for the processing of documents. The processing programs can check XML- documents for structural errors with the help of DTD. If there is no error then a document is valid! Well-formed documents contain no DTD- reference, but fulfill the XML-syntax-rules. Valid and well-formed documents

Accompanying Style Sheet File: 

Accompanying Style Sheet File

Presentation in MS IE 5.0 correspondently IE6.0 : 

Presentation in MS IE 5.0 correspondently IE6.0

Other Style Sheet File: 

Other Style Sheet File

Other presentation via XSL: 

Other presentation via XSL

Change of XML- documents: 

XML XSL XSL- Processor EDI/WML presentation for processing EDI: Electronic Document Interchange Change of XML- documents Conversion of XML- documents into workable formats (with the help of XSL-Style-Sheets) e.g. into EDI- formats for commercial data processing in the mobile field very interesting for conversion into WML!

System architecture, multidimensional: 

Application Server + WWW Server System architecture, multidimensional call data from EJBs and generate e.g. XML convert XML into *ML Access-Server Standardize access to Backend, create business logic

IBM Websphere Transcoding Publisher: 

IBM Websphere Transcoding Publisher syntax customization of content easy installation little administration effort changeable, expandable architecture of components

IBM Websphere Transcoding Publisher: 

IBM Websphere Transcoding Publisher WAP – capable mobile phone 7.Output of contents 1.Request over port xx Evaluation of used profiles Text Clipper: transforms HTML into WML Fragmentation Transcoder: Change into WML-decks &

Oracle Application Server Wireless Edition: 

Oracle Application Server Wireless Edition syntactic customization of content renewable, expandable architecture of components good customization of specific content

Oracle Application Server Wireless Edition: 

Oracle Application Server Wireless Edition Expiry of a user request

Oracle Application Server Wireless Edition: 

Oracle Application Server Wireless Edition Adapter and Transformer

Contents customization with XML / XSLT: 

Contents customization with XML / XSLT Separation of content and presentation content client- independent in XML XSLT: XSL transformations: a XML- data format is changed into a new data format (not necessarily XML), this new data format can include platform dependent information about the presentation of data besides the main information presentation client- dependent in some XSLTs XML-Support in many data bases the server itself needs additional logic

Contents customization with XML / XSLT: 

server-sided requests: reconnaissance and classification of the client choice of the suitable style sheets parameter handover to XSLT Processing of other documents (e.g. bitmaps) Contents customization with XML / XSLT

Example application: Pizza ordering service: 

Example application: Pizza ordering service content and logic in same XML-document no presentation-semantic in XML, so all client- abilities can be used in XSLT but stylesheets are not reusable

Example application: pizza ordering service: 

Example application: pizza ordering service <?xml version='1.0' encoding="ISO-8859-1" standalone="no" ?> <?xml-stylesheet type="text/xsl" href="Pizzaservices.xsl"?> <?xml-stylesheet type="text/xsl" href="Pizzaservices.lynx.xsl" media="lynx"?> <?xml-stylesheet type="text/xsl" href="Pizzaservices.lynx.xsl" media="palm"?> <?xml-stylesheet type="text/xsl" href="Pizzaservices.wap.xsl" media="wap"?> <?cocoon-process type="xsp"?> <?cocoon-process type="xslt"?> <xsp:page language="java" xmlns:xsp="http://www.apache.org/1999/XSP/Core"> <xsp:logic> class Item extends Vector { private int[] numbers; public Item () { super (); numbers= new int[10]; } public void setNumber (int nr, int a) { numbers[nr]=a; } public int getNumber (int nr) { return numbers[nr]; } } ...

Example application: pizza ordering service: 

<services> <service> <name>Hi Pizza</name> <banner>hellopizza.jpg</banner> <description>Hot Ware on Order</description> <location zipcode ="01277"> <address>Bodenbacher Strasse 16b, 01277 Dresden</address> <phone>03512540707</phone> <fax>03512540708</fax> </location > <location zipcode="01127"> <address>Mohnstraße 50, 01127 Dresden</address> <phone>03518485590</phone> <fax>03518485558</fax> </location > <proposal> <category name="Pizza"> <food> <name>Pizza Kentucky</name> <description>Salami</description> <price size="Normal">8.00</price> <price size="Jumbo">15.00</price> <price size="Pan">10.00</price> </food> ... Example application: pizza ordering service

Pizza ordering service: PC-presentation: 

Pizza ordering service: PC-presentation

Pizza ordering service: presentation on Palmscape and in WAP: 

Pizza ordering service: presentation on Palmscape and in WAP

XHTML: 

XHTML

XHTML: 

XHTML XHTML™ 1.0 is Extensible HyperText Markup Language (Second Edition) reformulation of HTML 4 in XML 1.0 use instead of WML2.0 correspondently cHTML (i-Mode) basis for integration between WAP2.0 and i-Mode WWW: http://www.w3.org/TR/xhtml1/#xhtml

XHTML: 

XHTML supporting via as well as WAP-Browsers also Netscape Navigator and Internet Explorer constituents: DTD (Document Definition) XSL (Extensible Stylesheet Language) large quantity of supported tags in comparison with WML2.0 and cHTML CSS frames tables forms/input fields applet calls

XHTML vs HTML: 

XHTML vs HTML XHTML describes data <-> HTML displays data! XHTML – combining HTML and XML, and their strengths XHTML is oriented to internet/PC and mobile internet/ mobile phones and hand helds XHTML - compatibility everything has to be marked up correctly -> "well-formed" documents pages can be read by all XML enabled devices upgrading of XML supported browsers compatibility to all browsers backward browser compatible

Slide356: 

Mobile agents

The agent- model: 

The agent- model an agent-system consists of the agents themselves and an execution engine for working with agents. The execution engine offers basic services to the agents Agent is an independent program generally, it consists of data, code and execution state, it works in interest and order of a third party (e.g. user, application).

Agent system: 

Hardware OS Hardware Operating system Hardware Operating System Agent system Network place 4 Place 3 Place 1 place 5

Agent model: 

Agent model migration: transfer of code, data, state local interactions with server transfer of the result

Properties of mobile agents: 

Properties of mobile agents Advantages: reduction of network load autonomy and asynchronity dynamic adapting in environment heterogeneity robustness and error tolerance scalability personalization and individualization dynamic code-installation encapsulation of protocols Disadvantages: need of special execution engine (Middleware) high security requirements transfer of code, data, state Decision: migration vs. remote communication

Applications: 

Applications E-commerce database requests intelligent e-mails Office applications/workflow traffic telematic Web surfing load balancing virtual enterprise Mobile computing

Existing agent systems: 

Existing agent systems Voyager (ObjectSpace) Aglets (IBM) Concordia (Mitsubishi Electric) Grasshopper (IKV++) Odyssey (General Magic) Mole (Stuttgart), Ara (Kaiserslautern) Agent TCL (Dartmouth University) MASIF (OMG) Telescript

Slide363: 

Middleware for spontaneous Networking

Vision: 

Vision JINI UPnP spontaneous networking of electrical devices (but not only computers) very simple connection platform independence

JAVA Intelligent Infrastructure, JINI: 

JAVA Intelligent Infrastructure, JINI „Middleware“ for spontaneous networking; originally developed from Sun JINI Connection Technology enables dynamic control of networked services and devices Partitioning into so called Lookup Groups: different sets of lookup-services basic operations: Discovery: offers locating of a directory services (lookup service) Join: enables acquaintance/ registration of the services implemented from some device

JAVA Intelligent Infrastructure, JINI: 

JAVA Intelligent Infrastructure, JINI Lookup-Service enables locating of services via other users/devices per lookup-operations Leasing offers time-limited allocation of resources (using of services) Jini integrates distributed events processing and distributed transactions further on for co-ordination between services

General procedure: step 1: 

Lookup service JINI device / service Client Discovery & join protocol Discovery lookup General procedure: step 1

General procedure: step 2: 

Lookup Service JINI device / service Client Proxy upload Proxy download General procedure: step 2

Slide369: 

JINI device / service Client Direct Connection General procedure: step 3 synchronization data exchange between Device and Client over own communication protocol

JINI - Details: 

JINI - Details Proxy hides all details of communication and is executed in the form of Client (dynamic installation of Stubs) security over RMI - Security Extension Framework new versions of JINI Starter Kits include advanced possibilities, for instance: Caching of request results by Clients unicast-discovery comfortable control of using period (lease) asynchronous receiving of events among other features further development via JINI Community: for instance JINI Surrogate Architecture: supports devices that do not have all required resources for JAVA and JINI printer working group

JINI - Assessment: 

JINI - Assessment suitable to support scenarios from the field of Ubiquitous/Pervasive Computing JINI is a part of JAVA 2 Micro Edition

Universal Plug and Play, UPnP: 

Universal Plug and Play, UPnP reply of Microsoft to JINI Embedded in UPnP- forum with this improvement corresponding to Plug- and- Play Standards, the PC peripheral devices should be connected to a home-network problem-less via Universal Plug and Play diverse devices can communicate with each other like with Jini

Universal Plug and Play, UPnP: 

Universal Plug and Play, UPnP essentially based on open standards like TCP/IP and therefore is compatible to each network in Windows ME integrated a special toolkit for creation of drivers on the basis of UPnP developed by INTEL

UPnP architecture: 

Home application Universal PnP Bus attached (ISA,PCI,USB, IEEE,1394,IR,..) Discovery Description Usage Internet Protocol attached Network media (Ethernet,HomeRF, HomePNA,.. IrDA X10 IR PLC .. .. Common Abstrac-tions Common Interfaces Media Indepen- dence UPnP architecture

Further approaches: 

Further approaches HAVi – Home Audio and Video Interop. essentially supported by the vendors of consumer-electronics field UPnP Forum is interlocked however represented more broadly on the market (specially also in computer-industry) HomePlug consortium for standardizing of data communication over (low voltage) power cable performance like by IEEE 802.11b the members are among others Cisco and Panasonic

Slide376: 

Services and system support for Mobile Computing

Mobile Computing: system support: 

Mobile Computing: system support Essential properties und requirements: dynamics, localization heterogeneity of networks and end-devices security problems

Mobile distributed applications: example: 

Product Data Main office Caching Client LAN-Access Maintenance technician - very different performance and charges: GSM, ISDN, LAN Software-technical, automatic adaptation to concrete system environment Example: Access to picture data/compressed picture data/graphics/text Mobile Access Local Resources, Error Protocols Mobile distributed applications: example

Problems and requirements: 

Problems and requirements Problem fields: dynamic system and net configuration dynamic change of Quality-of-Service-properties uncoupling/re-connection transparency of resource access security aspects Requirements: connection monitoring and selection treatment of uncoupling/off-sets and migration; emulation of services configuration update localization of mobile servers and clients advanced security and transaction services

Mobile RPC: 

Mobile RPC Goals: Mobile Binding Transparent call to an alternative server by non-accessibility Datagram RPC Queuing of calls in disconnected status Queued RPC intermediate storage and delivery of results after re-coupling Realization: Attachment on existent RPC- systems (without new implementation or internal code changes)

Slide381: 

Time Behavior Datagram RPC

Message Queuing: MQ Series example: 

Message Queuing: MQ Series example Base: Messages, Queues with Queue Manager dynamic coupling between applications and local Queues via logon/logoff using of Queues for transmission or receiving; also mixed using is possible coupling of distributed Queue Managers via Message Channels Internet Gateway, C++- and Java-Support support of essential operating system platforms

Example scenario: 

Example scenario decoupling of application through Queue Manager: Message forwarding is possible even if application isn’t running Computer A Queue Manager Queue Manager App- lication 1 MQPUT MQGET Computer B Queue Manager Queue Manager App- lication 2 MQGET MQPUT Message Channel

N:M - communication: 

N:M - communication A B C D E Queue, with optional support of message priorities Access to Server via multiple Clients Load balancing (selective delivery) or Parallel processing (replicated delivery)

Message Queuing: Assessment: 

Message Queuing: Assessment Advantages simple manageability robust message delivery flexible application fields (for instance load balancing, parallelization, batch-transmission of branch data etc.) relevant for easy coupling of programs, for instance via Internet, or for Mobile Computing Disadvantages limited communication semantics interaction model is different than with procedures/method invocations limited accessibility of higher services only several proprietary decisions up to now, only step-by-step standardization

Slide386: 

Ethernet Ethernet Ethernet E-Fax-Order Management DB-Access Firm Branch office Client X GSM xDSL Application Resource Mobile Station Communication path DB Distributed Database Distributed Database Cache Application Structure

Domain-concept: 

Domain-concept

Main functionality: Domain and Station Manager: 

Main functionality: Domain and Station Manager Domain Manager: management of all global objects (users, global available resources, stations, net topology) Station Manager: management of all local objects of a station (net access, running applications etc.)

Architecture of Station Manager: 

Architecture of Station Manager Authentication and Encryption Service Application Subsystem (Application Programming Interface) Subsystem (System Calls) Location Service Application Data Mobilizer and Manager Registry Service Bandwidth and Cost Management Service Disconnected Operation Handling Service (CS, QS, CHS, BMC) Active Database Resource Broker

Mobile Multimedia Email: message transfer: 

Mobile Multimedia Email: message transfer User Agent Message Store Email Proxy Queuing Service Subsystem Queuing Service message transfer Mobile Enhanced Message Handling System email protocol email protocol email protocol

Mobile Multimedia Email: selection of quality parameters: 

Mobile Multimedia Email: selection of quality parameters Cent Cent

Mobile File Manager: example CODA: 

Mobile File Manager: example CODA distributed file system, which offers the unbreakable access to data also in the case of server shut-down or net failure developed at the Carnegie Mellon University based on AFS (Andrew File System, distributed file system in UNIX-environment) relatively transparent to the applications

CODA overview: 

CODA overview based on the model of „Disconnected Operations” client keeps Read- and Write-access on the data via inset of a local buffer (Cache) also during temporary disconnection from net with re-connection system forwards changes and recognizes potential conflicts for different operating systems available (for instance LINUX, Solaris, Windows)

CODA system model: 

CODA system model Replicated Server: High availability Net communication at file open and close Client (“Whole-File-Caching”) Disconnected Client: local data access on Cache

properties of consistence (Coda): 

properties of consistence (Coda) Callback logic reference from server to the active client, used for immediate information about file changes via other client after connection failures the file in client cache remains valid till to timeout termination (as a rule several minutes) thereby reduced consistency conflict processing explicitly in interactive form, however low conflict probability

Conflict processing (CODA): 

Conflict processing (CODA) extensive automation as objective purpose, however isn’t possibly for: Update/Update-conflict: independent double update of the same file Delete/Update-conflict: independent erasure respectively update of the same file Name/Name-conflict: generating of two files with the same name Manual access after user notification

Cache management (Coda): 

Cache management (Coda) “Cache-Misses”: searched file isn’t in the Client-Cache processing failure in the disconnected status priority list of important files per user the highest priority is always kept in the cache (for instance by system programs, user profiles, address files etc.) other priorities: exchange strategies correspondent to importance dynamic generated files via list of essential operations referenced (for instance actual test protocol etc.)

Slide398: 

File synchronization under Windows Windows: over System Control -> Management -> Services so called „file replication (server)“ for synchronization of data between different servers under Explorer -> Extras -> Synchronization: - Synchronization of own Homepage with PC - Synchronization of Sites in WWW

Slide399: 

E-Hand http://www.ehand.com/ehand/ connects existing Enterprise Systems with mobile end-devices platform independent - very simple synchronization and data transfer - supports XML, ODBC and SyncML Advantages: - contains Web-similar user interface for application installation and for mobile participants

Slide400: 

E- Hand

Mobile databases support: 

Motivation: SFA-Sales-force-automation: -> actual information about clients, competitors and market trends to the field (outside-) workers emergent business transactions on the site -> efficiency increasing Example: Pharmaceutical Industry visit of 6 up to 8 distribution medics per day to bring dialogue to the point more quickly previous information about the medic (contacts, receipt prescription habits) are recallable from the firm-net presently still manually due to dialogue recording and product documentation in the future via mobile databases permanently faster access to data without inconvenient storage, connection establishment etc. Mobile databases support

Mobile databases support: 

mobile databases offer principally data synchronization and replication of enterprise servers and for mobile end-devices like PALM etc. due to increasingly mobile business processes there is a necessity of databases, which must perform these functionalities among other things: quickly compatible to as many as possible mobile systems 2 mobile database types: “asynchronous synchronization”: for instance SQL Remote of Sybase data replication between central database and multiple remote databases also offline-working is possible due to email-queuing principle (sent, if connected) “synchronous synchronization”: for instance Sybase Mobilink Synchronization Server co-operation with databases of other vendors (via Server Middleware) permanent connection necessary, for instance via GSM Mobile databases support

IBM DB2 Everyplace: 

IBM DB2 Everyplace compatible for instance to Windows CE, PalmOS, EPOC ... footprint: ~150 k (storage requirements) for data balancing DB Everyplace Sync Server is necessary synchronization with other Handhelds without PC! includes so called Mobile Devices Administration Center enables central management of all mobile end-devices of a enterprise supports integration of enterprise data from different databases and other sources (DB2 replication technology, JDBC, Adapter API for customized decisions) data are encrypted during synchronization (56 or 128 Bit) supports automatic conflict processing

IBM DB2 Everyplace: 

IBM DB2 Everyplace Source: http.//www.ibm.com Synchronization Server Backend IBM DB2 Microsoft Oracle Informix Sybase Other DBMS (JDBC) Mobile Devices

Oracle Lite: 

Oracle Lite 3 constituents: Oracle Lite DBMS database with low footprint (storage requirements) Java-enabled iConnect components for synchronization and creation of messaging-applications (principle of message queues) Web-to-go components supporting development, deployment and management of mobile Web-applications

Oracle Lite: 

Oracle Lite replication via Internet File-based replication

Sybase SQL Anywhere Studio: 

Sybase SQL Anywhere Studio mini-database, can be operated on the PDAs supports PalmOS, EPOC and WindowsCE small „footprint“: ~50kByte developer can adapt the database according to the required SQL-properties, modular design principle synchronization enables data balancing with the enterprises database, all well-known database vendors are supported only the changed data are transmitted both local (for instance B. Hotsync (Palm)) and remote synchronization supported architecture similar to IBM DB2 Mobile Connect (Source: http://www.sybase.com/products/anywhere/)

Further approaches: 

Further approaches Microsoft Mobile Information Server Lotus Everyplace numerous further products, mostly similar architecture concepts

Further sample applications: 

Further sample applications Traffic management Mobile Information Services M-Commerce Service technician Customer consultant Field workers in general Environmental engineering (measurement data logging) Medic (visits on site)

Traffic management: 

Traffic management Services: Traffic engineering Travel information Maintenance service Mobile Office Paris Berlin Dresden Service Center “Local” Provider “Global” Provider

Traffic management: 

GPS GSM PSTN/ ISDN End-user Distributed Service-Center Distributed Information services Traffic management

Application scenario: car maintenance: 

Printer Host Notepad HUB PC Terminal Application scenario: car maintenance

Online-information services: 

Client Client (mobile) low battery resource Server for instance WWW low band width Online-information services Client/Server-access by individual requests additionally: separate broadcast-channel from Server to the mobile Clients: transmission and caching of frequently requested information; thereby lower battery consumption (receiving less expensive as sending for the Client)

Optimization: basic concept: 

Optimization: basic concept information in Publication-Group: regular Broadcast information in On-Demand-Group: Client/Server-queries exchange between both groups on the basis of: access frequency (for instance on WWW-pages) page modification frequency channel bandwidths clients storage volumes (Cache)

Mobile e-Mail: 

Mobile e-Mail Quelle: http://www.eudora.com Eudora Internet Suite, consists of: Eudora email for the Palm computing platform EudoraWeb browser for the Palm Computing platform Eudora Mail Conduit Properties: Eudora and EudoraWeb browser support SSL (Secure Sockets Layer) and TLS (Transport Layer Security), i.e. end-to-end security synchronization of bookmarks between PC Web-Browser and EudoraWeb browser via Eudora Web Conduit synchronization with PC-Email applications several Email-accounts

Alternative M-Commerce applications: 

Alternative M-Commerce applications 12snap.de (pronounciation: “one two snap”) Auctioning channel www.paybox.de Cashless payments

Sample: 12snap system architecture: 

Sample: 12snap system architecture mobile radio net D2 center Offers via Cellular Broadcast external provider Call Center Automatic processing of the orders which are incoming via phone-service; also coupling of WAP and telephony Users are registered by 12snap and enable direct debit, respectively booking via the credit card; Orders are sent to a Call-Center via keyboard tone, client identification takes place via his phone number (CLIP = Calling Line Identification Presentation)

Sample: paybox.net: 

Sample: paybox.net Client is registered in the Internet by paybox.net and enables direct debit Client obtains as a result so called Paybox-PINs; using Paybox-PIN client can unblock the transactions purchase payments in the Internet are carried out as follows: Client selects „Paybox“ as a payment type Merchant sends transaction to Paybox-provider via secure data connection Provider dials up the clients via phone numbers stored in his master data then Client can unblock the transaction with his PIN Paybox transfers money via direct debit and forwards it to the Merchant