November 10 , 2010 IETF 79 – Beijing, China

A method for IP multicast performance monitoring

draft-cociglio-mboned-multicast-pm-01

Alessandro CapelloLuca CastaldelliMauro CociglioAlberto Tempia Bonda

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History

• First presented at IETF 77 in Anaheim• At IETF 78 the topic was presented in IPPM­ Outside the scope of the charter

• Update from -00 to -01­ Mainly editorial changes­ Added security considerations

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Motivation

• Artifacts seen by IPTV users are mainly related to Packet Loss­ IPTV service is sensitive to very low PL rates (10-4 and below)

• Develop PL monitoring tools for ISP’s multicast production network­ Provide to Network Operations Centers suitable views on network

behavior to address in near real-time complaints coming from Customer Care

­ Detect, measure and localize PL events

• Drive the implementation of network solutions to improve the Quality of Experience

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Service Providers requirements*

• SLA monitoring and verification­ Not only reachability test

• Fault localization­ Not only end-to-end measurement

• Inline data-plane measurement­ Performance measurements based on real user traffic

• Scalable solution• Self-contained

­ Not dependent on other protocols (RTP, IGMP, SNMP MIB, etc…)

* Requirements for IP multicast performance monitoring (draft-bipi-mboned-ip-multicast-pm-requirement-02)

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Characteristics

• The draft describes a monitoring methodology which fulfills the requirements of the previous slide

• In addition it is:­ vendor/technology independent­ with minimum impact on routers

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Performance measurement methodology

• Performance Monitoring Methodology steps:­ Marking of IPTV traffic­ Enabling packet counting / timestamp on router interfaces ­ NMS data retrieval­ NMS Performance Measurement and Fault Detection

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Principle of the method

• Mark multicast traffic being monitored so as to create a sequence of “blocks” and …

• … count the number of packets of each “block” to measure packet loss• … or take the timestamp of a particular packet within a block (f.i. the first

packet of each block) to measure delay / jitter

Block = sequence of consecutive packets with the same marking

Multicast Stream

MARKING

COUNTING COUNTINGCOUNTING

Blocks

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How it works (for packet loss)

Block 1 375 pcks 375 pcks 0 pcks lost

Block 2 382 pcks 382 pcks 0 pcks lost

Block 3 364 pcks 359 pcks 5 pcks lost

…

Block n-1 367 pcks 367 pcks 0 pcks lost

Block n 381 pcks 379 pcks 2 pcks lost

Block 1Block 2Block n Block n-1

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What is needed

• A bit of the IP header to mark the traffic• 2 counters on each interface on each router­ 1 counter for blue blocks­ 1 counter for orange blocks

• Note - Only one counter increases at a time:­ during blue blocks only the blue counter increases­ during orange blocks only the orange counter increases­ when a counter is still it can be read (block has terminated)

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And for delay and jitter?

Timestamp Timestamp Delay

Packet 1 11:21:07.483 11:21:07.4874 msec

Packet 2 11:22:08.621 11:22:08.6265 msec

…

Packet n-1 11:35:09.226 11:21:09.2326 msec

Packet n 11:36:08.790 11:22:08.7933 msec

Packet nTimestamp

Packet n-1Timestamp

Packet 2Timestamp

Packet 1Timestamp

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What it can measure

LinkMeasurement

NodeMeasurement

E2E Measurement

Segment by Segment Measurement

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Deployment considerations

• Multicast Flow Identification & Path Discovery­ How many flows? Which flows?

• Flow Marking­ Where? How?

• Packet counting on Monitoring Nodes­ Where? How?

• Management System­ It is required to collect and elaborate data

• Scalability­ How many flows can be monitored? How many nodes?

• Interoperability­ No issues

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Field deployment

• Field Trial started end 2009 in TI network:­ 2 real IPTV streams monitored­ 2 Metro Area Networks (MAN) involved: Turin and Naples

­ 30 nodes and 100 interfaces involved­ Rome MAN activation by end 2010

­ NMS prototype to collect, elaborate and visualize data­ Only packet loss measurement­ Preliminary results are very promising

­ Positive feedback from TI Operations

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Summary

• Easy implementation• Vendor/technology independent• Global or per-flow measurements• Highly precise packet loss measurement (single packet loss)• Applicable to any kind of traffic (unicast and multicast)

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Next steps

• Feedback and comments from the WG• Deployment extension to all 30 TI MANs• Extension to other kind of traffic (VoIP)