Discussion Items for Inter-Provider Service Performance Metrics

1. Discussion Items for Inter-Provider Service Performance Metrics Ralph Santitoro CTO Office rsantito@nortelnetworks.com Inter-Provider QoS Workshop at MIT October 20-21, 2004

2. Key Service Performance Metrics Rate of Service (RoS) / Bandwidth Profile Octet count per UNI/NNI, CoS aggregate or Flow per time Performance of Service (PoS) One Way Packet Delay (also looking at Round Trip) Packet Delay Variation Packet Loss Ratio Availability of Service (AoS) % of time PoS PMs are met over time interval

3. Bandwidth Profile Parameters Let’s agree on some common definitions for rate enforcement parameters 4 main parameters for each type of bandwidth profile <CIR, CBS, EIR, EBS, CM> CIR/CBS determines packet delivery per PoS objectives EIR/EBS determines amount of excess packet delivery CM (Color Mode) determines the whether packet color markings per CoS should be honored or ignored EIR ? PIR, EBS ? PBS PIR = CIR+EIR

4. Color Indications Green Packets conformant to CIR/CBS and SLA applicable per PoS parameters (delay, delay variation and loss) Yellow Packets not conformant with CIR/CBS but conformant with EIR/EBS and SLA not applicable Packets admitted to network but may be dropped under congestion Red Packets not conformant to CIR/CBS or EIR/EBS Packets typically dropped but may be admitted to network Red packets get dropped ahead of yellow packets

5. Rate Enforcement / Color from a Token Bucket Perspective Common parameters / definitions result in consistent service performance Metro Ethernet Forum trTCM algorithm for Ethernet services MEF 5 tech. spec. http://www.metroethernetforum.org/PDFs/Standards/MEF5.pdf http://www.ietf.org/internet-drafts/draft-aboulmagd-trtcm-inprofile-01.txt Applicable to Ethernet and IP services

6. NNI Bandwidth Profiles MEF has defined these for UNI. Some possible NNI variants below BW Profile to use depends upon type of service supported at NNI

7. Performance of Service (PoS) Packet Delay (One Way) P percentile of the delay of all successfully delivered Green packets per CoS over time interval T E.g., PD = 100ms 99.9% over 5 min. intervals Packet Delay Variation (a.k.a. jitter) P percentile of the difference of delays of green packet pairs within time interval T with inter-packet time interval of ?t Selection of ?t related to application E.g., PDV = 5ms 99.9% over a 5 min. intervals, ?t = 5ms Packet Loss Ratio Ratio of number of discarded green packets during time interval T to number of ingress green packets during the time interval T E.g., PLR = 0.1% over a 5 min. intervals

8. POS PM Zoning Zoning used with PoS PMs to factor in delay introduced due to distance

9. Performance of Service (PoS) Time Sync / Stamping Critical for one way delay/delay variation measurements IEEE 1588 highlights (http://ieee1588.nist.gov) Provides a deterministic injection and extraction of timestamp information at source and destination MACs to distribute frequency & optional phase aligned clock reference Sync messages sent at source (master) to end points (slaves) MAC injects precision timestamp –or- Follow-up message sent containing precise master sending time All slaves compute offset and correct their clocks Can be sent as UDP/IP packets or as native Ethernet packets

10. Availability of Service (AoS) Calculated via the following over time interval T Packet Delay, Delay Variation and Loss Ratio performance objectives being met UNI or NNI (L1) availability E.g., AoS = 99.9% calculated over 15 minute intervals Would be useful to have BCP guidelines for interval T / CoS T differs depending upon CoS performance objectives

11. PM Service Attribute Summary