Unlocking ECMP Programmability for Precise Traffic Control
summary
P-ECMP implements a programming model, compiler, and runtime that reuses seldom-used ECMP groups to deterministically steer flows; compiler inputs are topology JSON, desired policy (path-offset or exact next hop), and SRAM constraints, and it emits per-switch forwarding tables plus a transactional update to avoid inconsistency. Evaluation shows P-ECMP uses <1.5% of available ECMP groups (switches expose thousands), guarantees first-attempt reroute where prior random retries fail, reduces tail FCT versus PLB, and is deployed in Tencent cloud.
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chapters (11)
- 0:00ECMP programmability intro
- 1:19ECMP routing with hash functions
- 2:51Randomness limitations in ECMP
- 4:42Precise traffic control challenges
- 7:12Modifying ECMP mapping stage
- 9:19Two programming models
- 11:49PCMP compiler and deployment
- 13:38ECMP group consumption eval
- 14:19Network failover performance
- 15:20Load balancing results
- 16:03Production deployment and summary
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