050111 IMA

Diverse Network ServicesandRemaining Challenges: 

Diverse Network Services and Remaining Challenges SRCCS Winter 2005 Workshop on Internet Modeling and Analysis Sue B. Moon Division of Computer Science Dept. of EECS KAIST

Diverse Data Sets in Korea: 

Diverse Data Sets in Korea Data from major ISPs Non-existent in public Data from academia DAGMON traces at KAIST Long-term, sampled flow-level traces at POSTECH 4-month-worth NetFlow traces at CNU Others 3G video streaming service data 2-day packet-level traces from a home network

Diverse Data Sets in Korea: 

Diverse Data Sets in Korea Data from major ISPs Non-existent in public Data from academia DAGMON traces at KAIST Long-term, sampled flow-level traces at POSTECH 4-month-worth NetFlow traces at CNU Others 2-day packet-level traces from a home network 3G video streaming service data

2005.11.23 at KAIST: 

2005.11.23 at KAIST FTP HTTP P2P Others Others P2P FTP In Bits/Sec No. of Pkts / sec

2004.12.9. at KAIST: 

2004.12.9. at KAIST FTP HTTP P2P Others Others P2P In Bits/Sec No. of Pkts / sec

REMOVE after chat with SY: 

REMOVE after chat with SY Previous slides upstream or downstream? According to JH Youn Upstream 70%/85% (Bytes/Pkts) p2p Downstream Web and VOD more dominant that p2p.

Home Networking in Korea: 

Home Networking in Korea Architecture Simple, tree-like topology To each home = 100ME Internal links = 1GE Outbound speed = OC-3 or up Reality in new apt complexes Control home appliances thru the net washing machine, gas stove, lights, heater/airconditioner, door lock by PDAs at home or remotely by cellphones/web access Replace DSL/cable lines Will be "backbone" for home ubiquitous sensor network Need for remote monitoring Lack of resources

2004.12.11. at a Home Network: 

2004.12.11. at a Home Network

Video Streaming over 3G: 

Video Streaming over 3G Goals of Monitoring To satisfy every user: High revenue-generating customers More focus on per-user performance Challenges E2E performance segmented over cellular and wired networks No integrated monitoring solutions yet No good metric for overall/single-user performance

Provisioning for Interactive Streaming: 

Provisioning for Interactive Streaming Interactive Streaming Not a driving force behind b/w A candidate for growing revenue Examples VoIP gradually taking over PSTN traffic Remote video viewing at door by cell phone Online game traffic "Good" routing more important than bandwidth

Routing in the Internet: 

Routing in the Internet Intra-domain: shortest path routing Inter-domain: policy-based routing

Issues in "Good" Routing: 

Issues in "Good" Routing Misbehaving routing protocols BGP misconfigurations Pathological behaviors Frequent changes Even under normal circumstances Transient behaviors Inter/intra-domain routing not well understood

Scenario for a Transient Routing Loop In Normal Operation: 

Scenario for a Transient Routing Loop In Normal Operation

When a link fails, R1 is the first to detect.: 

When a link fails, R1 is the first to detect.

R3 is updated before R2.: 

R3 is updated before R2.

Finally R2 is updated, and the loop is resolved.: 

Finally R2 is updated, and the loop is resolved.

CDF of Routing Loop Duration in Time: 

CDF of Routing Loop Duration in Time

VoIP experimental setup [Boutremans2002]: 

VoIP experimental setup [Boutremans2002] Traffic injected in the network: 200 byte UDP packets every 5ms. Packets captured and timestamped at end-systems. Traceroute runs continuously during the experiment.

Information Sources: 

Information Sources IS-IS & BGP listener logs Router logs from both ends of “failing” links Controlled bi-directional VoIP traffic between Reston and ATL SNMP data

Delays (1 sec timescale): 

Delays (1 sec timescale)

When the two interfaces went down …: 

When the two interfaces went down … 6.6 seconds

When three links came back up …: 

When three links came back up …

Approaches To Fix It: 

Approaches To Fix It Fine-tuning parameters Timer values [Alattinoglu2002] Modify Routing Protocols Suppress advertisement and perform local rerouting using a backwarding table [Lee04] Centralized path computation [Feamster04,Rexford04]

Our Approach: 

Our Approach Key Idea: Find disjoint overlay path and send duplicate packets Assumptions Sender and receiver both within an AS Bidirectional link weights Extra income for extra b/w consumption Pros and cons Advantages No modification to current infrastructure Selective use by only those that need it Disadvantages Extra b/w consumption

Basic Ideas: 

Basic Ideas candidate relay nodes!!!

Resilient to Failures: 

Resilient to Failures

Future Work: 

Future Work Answer questions raised about diverse data sets Find best places for relay nodes in Inter-domain

BACKUP: 

BACKUP

Summary: Local Convergence: 

Summary: Local Convergence Convergence delay during failures hurts more After IS-IS converges, extra delay due to FIB update

Causes and Open Questions: 

Causes and Open Questions Why only after 30 secs? spf-interval set to 30secs What caused the 1.745 secs disruption? Unknowsn in GSR architecture What is the right timescale to propagate good news?