Slide 1: Simulation and Analysis of Wireless Network Using NS2 Department of Computer Science & Engineering
COLLEGE OF TECHNOLOGY AND ENGINEERING
Maharana Pratap University of Agriculture and Technology, Udaipur (India) 1/62 Simulation and Analysis of Wireless Network Using NS2 Presented By:
Ankush Badala, Gaurav Jain,
Hari Narayan Sanadhya and Jagdish
Slide 2: Why Simulation Study of implemented protocols and algorithms
Behavior
Performance
Test of unimplemented new protocols and algorithms
Comparison of results across research efforts Simulation and Analysis of Wireless Network Using NS2 2/62
Slide 3: Glimpse of Contents NS2 Introduction
Ns functionalities
“Ns” Components
Analysis of Ad-hoc Network Routing Protocols
To measure the loss rate, delay, jitter, throughput
Hidden Node and Exposed Node Problems
Throughput limit of IEEE-802.11b
References Simulation and Analysis of Wireless Network Using NS2 5/62
Slide 4: Introduction to NS-2 Simulation and Analysis of Wireless Network Using NS2 6/62
Slide 5: Introduction to NS-2 NS-2 is open source network simulator which is an invaluable tool for the researchers working on wired or wireless network.
NS-2 is developed by the VINT project in order to reduce duplication of effort within the network research and develop community. Simulation and Analysis of Wireless Network Using NS2 7/62
Slide 6: Ns functionalities Wired
Transportation agents: TCP,UDP
Traffic sources : web, ftp, telnet, cbr
Wireless
Ad hoc routing and mobile IP
Directed diffusion, sensor-MAC
Tracing, visualization, various utilities Simulation and Analysis of Wireless Network Using NS2 8/62
Slide 7: “Ns” Components Ns, the simulator itself
Nam, the network animator
Visualize ns (or other) output
Nam editor: GUI interface to generate ns scripts
Pre-processing:
Traffic and topology generators
Post-processing:
Simple trace analysis, often in awk, perl, or Tcl Simulation and Analysis of Wireless Network Using NS2 9/62
Slide 8: The simulation procedure Simulation and Analysis of Wireless Network Using NS2 10/62
Slide 9: Analysis of Ad-hoc Network Routing Protocols Simulation and Analysis of Wireless Network Using NS2 11/62
Slide 10: Wireless ad-hoc network 12/62 A collection of wireless mobile nodes forming a temporary network without the aid of any established infrastructure or centralized administration.
Each mobile node operates as a router as well as a host.
The Ad-hoc network protocols are classified as:-
Proactive protocols (DSDV)
Reactive protocols (DSR, AODV)
Significant differences to existing wired networks:-
Wireless
Self-starting
No administrator
Not necessary that every computer is within communication range
Possibly quite dynamic topology of interconnections Simulation and Analysis of Wireless Network Using NS2
Slide 11: Ad-hoc network classification Single hop
Nodes are in their reach area and can communicate directly
Multi hop
Some nodes are far and cannot communicate directly. The traffic has to be forwarded by other intermediate nodes Simulation and Analysis of Wireless Network Using NS2 13/62
Slide 12: DSDV Routing Algorithm Its proactive routing algorithm.
DSDV i.e. Destination Sequenced Distance Vector routing is modified Bellman-Ford routing algorithm.
Each node contains a routing table for each hop in the network.
Each node will periodically enter its entry to the routing table of all their neighbors.
Each entry is marked with a sequence number.
Lowest sequence number is the more favorable route.
Routing information is send by full dump and smaller incremental updates
Uses distance vector routing table. Simulation and Analysis of Wireless Network Using NS2 14/62
Slide 13: AODV Routing Algorithm Its reactive routing algorithm.
Ad Hoc On-Demand Distance Vector routing (AODV):
It uses hop-to-hop routing i.e. destination routing
When required to send information to the destination, it broadcasts
RREQ (route request) packet network wide and when RREQ reaches
destination, it unicasts RREP (route reply) packet to the source along
reverse path to the source of request.
Uses Route caching & timeout. 15/62 Simulation and Analysis of Wireless Network Using NS2
Slide 14: DSR Algorithm DSR (Dynamic Source Routing)
Reactive routing algorithm
A node maintains route cache containing the routes it knows
Include route discovery on request and route maintenance when needed
Uses source routing
DSR Terminology
Route discovery
Route Maintenance 16/62 Simulation and Analysis of Wireless Network Using NS2
Slide 15: Test methodology All test are based on the following network scenario:-
100 wireless nodes
Terrain area 300m x 300m, 300m x 500m, 500m x 500m
Simulation time of 100 sec
3 different pause time – 0 sec, 50 sec, 100 sec
Channel bandwidth 2 Mbps
Packet rate of 4 packets/sec
Packet size is of 512 bytes
Simulator used NS2 over windows xp environment Simulation and Analysis of Wireless Network Using NS2 17/62
Slide 16: Performance metrics Data Packet Delivery Fraction
Average End-to-End Delay Simulation and Analysis of Wireless Network Using NS2 18/62
Slide 17: Outcome (1/4) Pause time versus packet delivery functi-on when terrain area is 300m x 300m Pause time versus packet delivery functi-on when terrain area is 300m x 500m Simulation and Analysis of Wireless Network Using NS2 19/62
Slide 18: Outcome(2/4) From these graphs, it can be concluded that packet delivery fraction for DSR is best as compared to AODV and DSDV, respectively under varying terrain areas and pause time. Pause time versus packet delivery function when the terrain area is 500m x 500m Simulation and Analysis of Wireless Network Using NS2 20/62
Slide 19: Outcome(3/4) Pause time versus average end-to-end delay when the terrain area is 300m x 300m Pause time versus average end-to-end delay when the terrain area is 300m x 500m Simulation and Analysis of Wireless Network Using NS2 21/62
Slide 20: Outcome(4/4) These graphs reveals that under varying terrain areas and pause time, average end-to-end for DSR is best as compared to AODV and DSDV, respectively Pause time versus average end-to-end delay when the terrain area is 500m x 500m Simulation and Analysis of Wireless Network Using NS2 22/62
Slide 21: Winding up The general observation from the simulation gives an idea that even if the terrain area of the network scenario is changed, the behavior of these routing protocols remains the same provided the number of nodes and the load on the system is the same, showing the Overall performance of DSR (in terms of DPDF and AED) is better than AODV and DSDV. Simulation and Analysis of Wireless Network Using NS2 23/62
Slide 22: To measure the loss rate, delay, jitter
and throughput Simulation and Analysis of Wireless Network Using NS2 24/62
Slide 23: Illustrating the network performance metrics for wireless network scenario including
packet loss rate
End-to-End delay of packets
Jitter
Throughput. Objective Simulation and Analysis of Wireless Network Using NS2 25/62
Slide 24: Introduction (1/2) Routing protocols in conventional wireless networks
Destination-Sequenced Distance-Vector (DSDV)
Packets are transmitted between the stations of the network by using routing tables which are stored at each station of the network.
Each node maintains a list of all destinations and number of hops to each destination. Routing information is distributed between nodes by sending full dumps infrequently and smaller incremental updates more frequently. Simulation and Analysis of Wireless Network Using NS2 26/62
Slide 25: The advantages of DSDV
It is quite suitable for creating ad hoc networks with small number of nodes
solve the Routing Loop problem
The Disadvantages of DSDV
DSDV requires a regular update of its routing tables, which uses up battery power and a small amount of bandwidth even when the network is idle.
DSDV is not suitable for highly dynamic networks. Introduction (2/2) Simulation and Analysis of Wireless Network Using NS2 27/62
Slide 26: Performance metrics (1/2) packet loss rate
Describes how many packets were lost in transit between the source (or input) and the destination (or output)
End-to-End delay (seconds)
It consists of the time passing between the moments in which the packet flow is transmitted and the moment in which it is available at the destination. Simulation and Analysis of Wireless Network Using NS2 28/62
Slide 27: Performance metrics (2/2) Jitter
Refers to the variation in time between packets arriving at the destination, it is caused by network congestion, timing drift, or route changes.
Here,
e2e_delay = End-to-End delay of current packet,
last_ e2e_delay = End-to-End delay of next packet
Throughput (bps)
It describes the rate of the packet measured as an average or peak. It is the effective rate of data sent obtained by the sender in transmission. Simulation and Analysis of Wireless Network Using NS2 29/62
Slide 28: Simulation setup The simulation
The area in which the simulation carried out - 800m*800m
No. of nodes – 3 with one mobile
Velocity of a mobile node - 2.0~5.0m/s
Transmission range - 250m
Size of packets -1000 bytes
Simulation time – 500 sec
Traffic type – Constant Bit Rate (CBR)
The bandwidth for transmitting data is 2Mb/s
Antenna Type – Omni Antenna Simulation and Analysis of Wireless Network Using NS2 30/62
Slide 29: The simulation results and analysis for different QoS matrices:
Packet loss rate
End-to-End delay (seconds) Figure1. Delay Vs Packet Sequence Simulation and Analysis of Wireless Network Using NS2 Graphs (1/3) 31/62
Slide 30: Jitter Figure2. Packet start time Vs Jitter Graphs (2/3) Simulation and Analysis of Wireless Network Using NS2 32/62
Slide 31: Throughput (bps) Figure3. Time Vs Throughput Simulation and Analysis of Wireless Network Using NS2 Graphs (3/3) 33/62
Slide 32: Summing Up Measurement of the performance of different QoS metrics for wireless networks using ns-2 simulations are as follows:
Total packet loss is : 44.0677%
From the result shown in figure-3 previously
average throughput rate is : 2588.45314982873 bps
peak throughput rate is : 8320 bps Simulation and Analysis of Wireless Network Using NS2 34/62
Slide 33: Hidden Node and Exposed Node
Problems Simulation and Analysis of Wireless Network Using NS2 35/62
Slide 34: Node N0 can sense nodes N1 and N2.
Nodes N1 and N2 can’t sense each other.
Problem: coordinate transmissions from N1 and N2 so as to avoid collisions. The Hidden Node Problem N1 N0 N2 Simulation and Analysis of Wireless Network Using NS2 36/62
Slide 35: Physical Hidden Node: occurs when the hidden node transmits after the interfered node.
Protocol Hidden Node: occurs when the hidden node started transmitting before the interfered node. The Hidden Node Problem Simulation and Analysis of Wireless Network Using NS2 37/62
Slide 36: A sender (node 3) transmits to a receiver (node 4) at a distance d away any node within the interference range - represented by the circle centered at node 4 with radius Ri - may potentially interference with the transmission from node 3 to 4 .
The shaded area in Fig represents the area where potential physical hidden nodes reside. In particular, when node 3 is transmitting to node 4, node 1’s transmission to node 2 will cause physical hidden node type of collision. Since this hidden node problem is a function of the physical interference range, we named it the PHYSICAL HIDDEN NODE PROBLEM. Simulation and Analysis of Wireless Network Using NS2 38/62
Slide 37: This problem occurs when sender is not able to hear as far as the receiver. The cross-lined area which can be heard by receiver (node 4) is out of the sensing range of the sender (node 3).
When a transmission from node 5 to node 6 is started first, any node hearing this transmission will be ’stationary’. This means node 4 shuts itself down from receiving. But the sender (node 3) has no idea about what is taking place at node 5 (the interfering hidden node). To node 3, the channel is idle. Therefore, node 3 would transmit to node 4 while the transmission of node 5 is in progress.
A collision will occur, since no ACK or CTS will be sent to node 3 by node 4. In this case, since the hidden node problem is caused by the limitation of the protocol, we name it PROTOCOL HIDDEN NODE PROBLEM. Simulation and Analysis of Wireless Network Using NS2 39/62
Slide 38: RTS/CTS/DATA/ACK handshake – N1 sends RTS to N0, N0 sends CTS to N1, N2 hears CTS and stays quiet, N1 sends DATA to N0, N0 replies to N1 with an ACK. Solution (RTS/CTS) N1 N0 N2 Simulation and Analysis of Wireless Network Using NS2 40/62
Slide 39: a node waiting to transmit a packet will first transmit a short control packet called Request To Send (RTS) which includes the source, destination and the duration of the following transaction (the packet and the respective ACK).
If the medium is free, the destination station responds with a response control packet called Clear To Send (CTS) which includes the same duration information. All stations receiving either RTS and/or CTS, set their Virtual Carrier Sense indicator (called NAV, for Network Allocation Vector), for the given duration and use this information together with the Physical Carrier Sense when sensing the medium. Simulation and Analysis of Wireless Network Using NS2 41/62
Slide 40: The mechanism reduces the probability of a collision on the receiver area by a station that is “hidden” from the transmitter to the short duration of the RTS transmission because the station hears the CTS and “reserves” the medium as busy until the end of the transmission.
Due the short frames of RTS and CTS, the method also reduces the overhead of collisions.
The situation in which the RTS/CTS are very helpful is the outdoor point-to-multi-point environment in which the hidden node problem can be a larger problem. Simulation and Analysis of Wireless Network Using NS2 42/62
Slide 41: A B C D The Exposed Node problem An exposed node is one that is in range of the transmitter, but outside range of the receiver. Simulation and Analysis of Wireless Network Using NS2 43/62
Slide 42: Simulations were performed involving three nodes (N0, N1 and N2) in a 500mx500m terrain area. Different scenarios are generated by varying the distances and between nodes N0 and N2.
The transmission range and the sensing range are deliberately set to the same value of 100 meters, to eliminate any possible effects of the sensing range.
The parameters used in this simulation are shown in the table. Simulations Simulation and Analysis of Wireless Network Using NS2 44/62
Slide 44: Scenario when the distance between node N0 and N1 is 100m and 100m between node N0 and N2 without RTS/CTS
From “sd1”, node N1 sends out 1688 packets. From “rd1”, node N0 receives 167 packets. From “sd2”, node N2 sends out 1626 packets. From “rd2”, node N0 receives 83 packets.
With RTS/CTS
From “sd1”, node N1 sends out 1688 packets. From “rd1”, node N0 receives 746 packets. From “sd2”, node N2 sends out 1626 packets. From “rd2”, node N0 receives 782 packets. Simulation and Analysis of Wireless Network Using NS2 46/62
Scenario when the distance between node N0 and N1 is 100m and 150m between node N0 and N2 : Scenario when the distance between node N0 and N1 is 100m and 150m between node N0 and N2 without RTS/CTS
From “sd1”, node N1 sends out 1688 packets. From “rd1”, node N0 receives 1559 packets. From “sd2”, node N2 sends out 1626 packets. From “rd2”, node N0 receives 0 packets.
with RTS/CTS
From “sd1”, node N1 sends out 1876 packets. From “rd1”, node N0 receives 1451 packets. From “sd2”, node N2 sends out 1688 packets. From “rd2”, node N0 receives 0 packets. Simulation and Analysis of Wireless Network Using NS2 47/62
Slide 46: The results reveal that the presence of a hidden node in a network can result in an order of magnitude increase in DATA packet loss compared to a network without RTS/CTS nodes.
But when distance between nodes increases more than transmission range then this method is not much of use. Upshot Simulation and Analysis of Wireless Network Using NS2 48/62
Slide 47: Throughput limit of
IEEE-802.11b Simulation and Analysis of Wireless Network Using NS2 49/62
Slide 48: IEEE 802.11b ? (1/2) IEEE has developed specifications for different types of networks to ensure interoperability between network components
IEEE 802.11 addresses wireless LANs
The specifications deal with the Physical and Data Link layers of the OSI Model
A wireless station, or client, consists of a PC equipped with a wireless network interface card (NIC)
An access point (AP) consists of a radio, a wired network interface and bridging software.
Ethernet uses carrier sense, multiple access with collision detection (CSMA/CD) to deal with simultaneous transmissions Simulation and Analysis of Wireless Network Using NS2 51/62
Slide 49: IEEE 802.11b ? (2/2) Wireless clients cannot use CSMA/CD
A client cannot detect a hidden node, so simultaneous transmissions are more likely
The transmissions from wireless clients overpower reception and they cannot detect collisions
Wireless systems use carrier sense, multiple access with collision avoidance (CSMA/CA)
A client broadcasts the data
The access point sends an ACK when it receives the transmission
If the client doesn’t receive an ACK, it retransmits the data Simulation and Analysis of Wireless Network Using NS2 52/62
Slide 50: CSMA / CA Simulation and Analysis of Wireless Network Using NS2 53/62
Slide 51: IEEE 802.11 frame format Simulation and Analysis of Wireless Network Using NS2 54/62
Slide 52: THROUGHPUT CALCULATIONS Simulation and Analysis of Wireless Network Using NS2 55/62
Slide 53: SIMULATION PARAMETERS Simulation and Analysis of Wireless Network Using NS2 56/62
Slide 54: Results (1/2) Simulation and Analysis of Wireless Network Using NS2 57/62
Slide 55: Results (2/2) Simulation and Analysis of Wireless Network Using NS2 58/62
Slide 56: Inference Simulation and Analysis of Wireless Network Using NS2 The Throughput Limit (TL) exists for all IEEE 802.11 standards.
For a given set of parameters and a given payload size, the TL is a fixed number
Increasing the TL can be done by reducing the overhead of the parameters.
It is evident that in all the scenarios, maximum MAC throughput improved as the MSDU size increased and they follow the similar trend. 59/62
Slide 57: References (1/2) Broch J., Maltz D., Johnson D., Y. Hu, and Jetcheva J: A performance comparison of multi-hop wireless ad hoc network routing protocols.
Azzedine Boukerche "Performance Evaluation of Routing Protocols for Ad Hoc Wireless Networks." Mobile Networks and Applications 9, 333-342, 2004, Kluwer Academic Publishers, Netherlands.
C. Cheng, R. Riley, Srikanta P. R. Kumar, J. J. Garcia-LunaAceves : A Loop free Bellman-Ford reouting protocol without bouncing effect. In ACM SIGCOMM'89, pages 224237,September 1989.
ns-2 network simulator: http://www.isi.edu/nsnam/ns [November 21, 2006].
Ian D. Chakeres and Elizabeth M. Belding-Royer. AODV Routing Protocol Implementation Design Simulation and Analysis of Wireless Network Using NS2 60/62
Slide 58: References (2/2) Broch J., Maltz D., Johnson D., Y. Hu, and Jetcheva J: A performance comparison of multi-hop wireless ad hoc network routing protocols.
Azzedine Boukerche "Performance Evaluation of Routing Protocols for Ad Hoc Wireless Networks." Mobile Networks and Applications 9, 333-342, 2004, Kluwer Academic Publishers, Netherlands.
C. Cheng, R. Riley, Srikanta P. R. Kumar, J. J. Garcia-LunaAceves : A Loop free Bellman-Ford reouting protocol without bouncing effect. In ACM SIGCOMM'89, pages 224237, September 1989.
ns-2 network simulator: http://www.isi.edu/nsnam/ns [November 21, 2006].
S. Bradner, “Benchmarking terminology for network interconnection devices”, RFC 1242, July 1991
S.Bradner, J. McQuaid, Benchmarking Methodology for Network Interconnect Devices”, RFC 2544, March 1999 Simulation and Analysis of Wireless Network Using NS2 61/62
Slide 59: Thanks for your kind attention! 62/62 Simulation and Analysis of Wireless Network Using NS2