Tiziana Ferrari Differentiated Services Test: Report1 Differentiated Service Test REPORT TF-TANT Tiziana Ferrari Frankfurt, 1 Oct 1999

Tiziana Ferrari Differentiated Services Test: Report2 Overview Differentiated Services Architecture test activities test infrastructure interim results QoS measurement test plan Services

Tiziana Ferrari Differentiated Services Test: Report3 Differentiated Services Architecture

Tiziana Ferrari Differentiated Services Test: Report4 Differentiated services Why diffserv? –new technology –independent of layer 2 technologies –interoperability between independent national research networks (different requirements, infrastructures, policies and management) –traffic aggregation –scalability –no signalling –QoS for networks not ATM based cont.

Tiziana Ferrari Differentiated Services Test: Report5 Diffserv architecture: components DS field (1 byte) packet classification packet scheduling traffic conditioning: –metering –marking –policing –shaping DS field CU 067

Tiziana Ferrari Differentiated Services Test: Report6 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: Report7 Diffserv architecture: network model DS domain Non DS capable domain MPLS NRN TEN-155 marking Marking policing scheduling shaping DS domain

Tiziana Ferrari Differentiated Services Test: Report8 Test activities: test plan current status future tests

Tiziana Ferrari Differentiated Services Test: Report9 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: Report10 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: Report11 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: Report12 Test infrastructure

Tiziana Ferrari Differentiated Services Test: Report13 Test network

Tiziana Ferrari Differentiated Services Test: Report14 LAN layout (example)

Tiziana Ferrari Differentiated Services Test: Report15 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: Report16 Interim Results

Tiziana Ferrari Differentiated Services Test: Report17 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: Report18 CAR: test of exceed actions Throughput: SWITCH: 1.20 Mbps DANTE: 0.38 Mbps

Tiziana Ferrari Differentiated Services Test: Report19 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: Report20 CAR: TCP burst tolerance (cont)

Tiziana Ferrari Differentiated Services Test: Report21 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: Report22 CB-WFQ: set-up

Tiziana Ferrari Differentiated Services Test: Report23 CB-WFQ: traffic isolation of a single TCP stream

Tiziana Ferrari Differentiated Services Test: Report24 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: Report25 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: Kbps guaranteed (8% PPP link bw) Assured: Kbps (40% PPP bw)

Tiziana Ferrari Differentiated Services Test: Report26 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: Report27 IBM: EF policing (cont) EF with TCP traffic, target rate = 163 Kbps

Tiziana Ferrari Differentiated Services Test: Report28 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: Report29 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: Report30 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: Report31 More information at Test programme: – more info and test results: –