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Differentiated Services Test Report: Overview of Architecture and Activities

This report covers the architecture and activities of Differentiated Services testing, including test infrastructure, interim results, QoS measurements, and future plans. It showcases components, PHBs, network models, and equipment used in the testing.

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Differentiated Services Test Report: Overview of Architecture and Activities

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  1. Differentiated Service TestREPORT TF-TANT Tiziana Ferrari ferrari@cnaf.infn.it Frankfurt, 1 Oct 1999 Tiziana Ferrari Differentiated Services Test: Report

  2. Overview • Differentiated Services Architecture • test activities • test infrastructure • interim results • QoS measurement test plan • Services Tiziana Ferrari Differentiated Services Test: Report

  3. Differentiated ServicesArchitecture Tiziana Ferrari Differentiated Services Test: Report

  4. Differentiated services cont. • Why diffserv? • new technology • independent of layer 2 technologies • interoperability between independent national research networks (different requirements, infrastructures, policies and management) • traffic aggregation • scalability • nosignalling • QoS for networks not ATM based Tiziana Ferrari Differentiated Services Test: Report

  5. Diffserv architecture: components • DS field (1 byte) • packet classification • packet scheduling • traffic conditioning: • metering • marking • policing • shaping 0 6 7 CU DS field Tiziana Ferrari Differentiated Services Test: Report

  6. Diffserv architecture: PHBs • Per Hop Behaviours: description of the packet treatment into the network • Standardised PHBs: • Expedited Forwarding (low delay, low delay variation, guaranteed bandwidth) • Assured Forwarding (Behaviour Aggregate, 4 classes, 3 drop priorities per class) • Experimental PHBs • PHB class selectors: XXX000 (backward compatibility with TOS precedence) Tiziana Ferrari Differentiated Services Test: Report

  7. Diffserv architecture: network model DS domain NRN DS domain MPLS Non DS capable domain DS domain NRN Marking policing scheduling TEN-155 marking shaping DS domain DS domain Tiziana Ferrari Differentiated Services Test: Report

  8. Test activities: test plan current status future tests Tiziana Ferrari Differentiated Services Test: Report

  9. Programme overview • Diffserv architecture (precedence, DSCP) • test of QoS features in routers • parameter tuning • interoperability • mixed diffserv-intserv architecture (end-to-end QoS) • mixed diffserv-MPLS architecture • QoS measurement • Policy management Tiziana Ferrari Differentiated Services Test: Report

  10. Work accomplished (from end of June 99) • network configuration • baseline performance testing • CISCO: • CAR (Committed Access Rate): functionality and parameter tuning • CB-WFQ (Class Based WFQ): traffic isolation • IBM: • policing of EF traffic • SCFQ (Self Clocked Fair Queuing): EF, AF and best-effort • configuration of GPS capable QoS measurement equipment (SmartBits by Netcom Systems) • diffserv deployment by a test application: MONARC • definition of test services • definition of QoS measurement test plan Tiziana Ferrari Differentiated Services Test: Report

  11. Future activities • Weighted Random Early Discard (WRED) testing • completion of IBM testing • study of TCP related issues: ACK colouring, TCP and UDP aggregations with AF • interoperability testing (other future platforms: NORTEL, TELEBIT, TORRENT, Linux) • service testing • QoS performance measurement • diffserv and MPLS • diffserv and intserv • policy management and bandwidth brokerage Tiziana Ferrari Differentiated Services Test: Report

  12. Test infrastructure Tiziana Ferrari Differentiated Services Test: Report

  13. Test network Tiziana Ferrari Differentiated Services Test: Report

  14. LAN layout (example) Tiziana Ferrari Differentiated Services Test: Report

  15. Equipment • Test workstations • traffic generators (3 SmartBits, Netcom System loan) • ATM switches in the test sites • cabletron ethernet switch • DS capable routers: • C7200 or C7500 (partial CISCO loan) • IBM 2212 and IBM 2216 (2 routers in 5 sites, IBM donation) Tiziana Ferrari Differentiated Services Test: Report

  16. Interim Results Tiziana Ferrari Differentiated Services Test: Report

  17. CISCO: CAR • Multi-field classification: OK • packet marking (precedence setting): OK • exceed action testing: OK • policing (at a configurable rate): two parameters token bucket for TCP performance optimisation • normal burst • exceed burst --> parameter tuning Tiziana Ferrari Differentiated Services Test: Report

  18. CAR: test of exceed actions Throughput: SWITCH: 1.20 Mbps DANTE: 0.38 Mbps Tiziana Ferrari Differentiated Services Test: Report

  19. CAR: TCP burst tolerance • Normal and exceed burst tuning with TCP traffic • single and multiple TCP streams optimum values are functions of the rate R at which traffic is policed, in particular: normal burst = 0.5 sec * R exceed burst = 2 * normal burst Tiziana Ferrari Differentiated Services Test: Report

  20. CAR: TCP burst tolerance (cont) Tiziana Ferrari Differentiated Services Test: Report

  21. CISCO: CB-WFQ Scheduling mechanism to provide minimum bandwidth guarantees to classes • class definition: precedence or MF classification --> OK • bandwidth allocation: no starvation, no bandwidth consumption --> OK • traffic isolation: scenarios • UDP high priority + UDP best-effort • TCP high priority + UDP best-effort • TCP high priority + TCP best-effort UDP --> OK (always) TCP: inconsistency Tiziana Ferrari Differentiated Services Test: Report

  22. CB-WFQ: set-up Tiziana Ferrari Differentiated Services Test: Report

  23. CB-WFQ: traffic isolation of a single TCP stream Tiziana Ferrari Differentiated Services Test: Report

  24. CB-WFQ: traffic isolation of multiple TCP streams Multiple TCP streams get the bandwidth share as defined by CB-WFQ! Tiziana Ferrari Differentiated Services Test: Report

  25. IBM: Self Clocked Fair Queuing • Policy = (traffic profile, validity period, diffserv action) • diffserv action = (type of marking, queue type, bandwidth) • optimum traffic isolation (tests only with UDP) Premium: 163.8 Kbps guaranteed (8% PPP link bw) Assured: 819.2 Kbps (40% PPP bw) Tiziana Ferrari Differentiated Services Test: Report

  26. IBM: EF policing Small TCP burst tolerance in a policer can completely starve a TCP stream. Token bucket depth is key parameter --> tuning need according to the rate at which traffic is policed Tiziana Ferrari Differentiated Services Test: Report

  27. IBM: EF policing (cont) EF with TCP traffic, target rate = 163 Kbps Tiziana Ferrari Differentiated Services Test: Report

  28. QoS measurement • Resource allocation monitoring • for resource allocation and network dimensioning • performance measurement • passive • active (invasive traffic) • for service validation • to understand the effect on end-to-end performance of buffering in one router or in a chain Tiziana Ferrari Differentiated Services Test: Report

  29. Performance measurement • parameters of interest: • one-way delay, requirements: clock synchronisation • GPS based synchronisation • SmartBits (Netcom Systems) • NTP (Network Time Protocol) • NTP client / server hierarchy • one-way delay variation • packet loss • throughput • RTT Tiziana Ferrari Differentiated Services Test: Report

  30. Services: examples • Virtual leased line: • point to point • one to many • capacity allocation on congested links (e.g. US links) • better-than-best-effort (qualitative definition) • delay bound and delay variation sensitive traffic classes • rate limiting of invasive traffic • ... Tiziana Ferrari Differentiated Services Test: Report

  31. More information at • Test programme: • http://www.cnaf.infn.it/~ferrari/tfng/diffserv.html • more info and test results: • http://www.cnaf.infn.it/~ferrari/tfng/ds-test.html Tiziana Ferrari Differentiated Services Test: Report

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