Transcript mboned-1
A method for IP multicast performance monitoring draft-cociglio-mboned-multicast-pm-00 Alessandro Capello Luca Castaldelli Mauro Cociglio Alberto Tempia Bonda March 22 , 2010 IETF 77 – Anaheim, USA 1 Motivation • Artifacts seen by IPTV users are mainly related to Packet Loss (PL) - 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 MBONED WG draft-cociglio-mboned-multicast-pm-00 2 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-pmrequirement-00.txt) MBONED WG draft-cociglio-mboned-multicast-pm-00 3 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 MBONED WG draft-cociglio-mboned-multicast-pm-00 4 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 MBONED WG draft-cociglio-mboned-multicast-pm-00 5 Principle of the method • Mark multicast traffic being monitored so as to create a sequence of “blocks” and … MARKING Blocks Block = sequence of consecutive packets with the same marking Multicast Stream COUNTING COUNTING COUNTING • … 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 MBONED WG draft-cociglio-mboned-multicast-pm-00 6 How it works (for packet loss) Block n Block n-1 Block 2 Block 1 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 … MBONED WG draft-cociglio-mboned-multicast-pm-00 7 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 (the block terminated) MBONED WG draft-cociglio-mboned-multicast-pm-00 8 And for delay and jitter? Packet n Timestamp Packet n-1 Timestamp Packet 2 Timestamp Packet 1 Timestamp Timestamp Timestamp Delay Packet 1 11:21:07.483 11:21:07.487 4 msec Packet 2 11:22:08.621 11:22:08.626 5 msec Packet n-1 11:35:09.226 11:21:09.232 6 msec Packet n 11:36:08.790 11:22:08.793 3 msec … MBONED WG draft-cociglio-mboned-multicast-pm-00 9 What it can measure Segment by Segment Measurement Link Measurement Node Measurement E2E Measurement MBONED WG draft-cociglio-mboned-multicast-pm-00 10 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 MBONED WG draft-cociglio-mboned-multicast-pm-00 11 Field Trial • Field Trial started end 2009 in Telecom Italia network: - 2 real IPTV streams monitored - 14 nodes and 50 interfaces involved - NMS prototype to collect, elaborate and visualize data - Only packet loss measurement - Preliminary results are very promising MBONED WG draft-cociglio-mboned-multicast-pm-00 12 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) MBONED WG draft-cociglio-mboned-multicast-pm-00 13 Next steps • Feedback and comments from the WG • Feedback from the Field Trial • Extension to other kind of traffic (VoIP) MBONED WG draft-cociglio-mboned-multicast-pm-00 14