1 Sub-IP Protection Methods of Measurement: Considerations Al Morton bmwg Chair IETF-72

2 Outline Review Existing Methods of Measurement and the Benchmarks they produce. Take bmwg-wide feedback into account Consider implications on the Sub-IP Protection Work

3 Reference Model Pseudo Failure Node ANode B Primary Path Recovery Path Initiate TX Packets Verify RX Packets Trigger Test Equipment Working Path = Currently forwarding packets

4 Example Methodology: OSPF Data Plane Convergence Traffic Receiver Router 1 Router 3 Router 2 Preferred Link Link 1 Link 2 Inject OSPF Routes Source Test Port Dest. Test Ports Tester_1 Tester_2 Traffic Blaster Local Remote Back-up Link X Time System Under Test

5 Recovery Time (Perser and Kimura, IETF-57, 2002) There are five externally observable effects during Recover Time Lost packets Induced delay Out-of-order packets Duplicate packets Errored packets 1267 Most accurate measurement takes into account all five effects

6 3 Methods for Failover & Reversion Time Measurement (3.6) Packet Loss-Based Method (3.6.2) –Number of lost packets/offered load rate –Produces a “typical” failover time, not max or min Time-Based Loss Method (3.6.1) –The duration of non-zero packet loss –Produces a max failover time w.r.t. Loss only Timestamp-Based Method (3.6.3) –The duration of “impaired packet arrivals” –Impairments are Lost, Reordered and Duplicate –Timestamps in packets –Produces a max failover time w.r.t. Impairments

7 Observations Failover and Reversion Times will be very short (e.g. 50ms to 200ms), w.r.t. convergence times. Failover may only be possible for a fraction of the traffic on the Primary Path –MAY need a Route-Specific Methodology, as in the IGP Dataplane work. Reversion likely to be Loss-less, and may only exhibit Reordering or Duplication –Loss-dependent methods will confirm that aspect Min, Ave, and Max IGP Convergence times were seen as valuable (for specific flows)

8 Recommendations? Discuss further on the list