Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 325

17 Equal Cost Multi-Path ECMP for Flow-based Affinity e ECMP for Flow-based Affinity is available only platform: The hashing algorithm on E-Series TeraScale and E-Series ExaScale are different. Hashing on ExaScale is based on CRC, checksum, or XOR, and the algorithm on TeraScale is based on checksum only. If flow-based affinity is to be maintained by an ExaScale and TeraScale chassis, they must both use the same hashing algorithm and seed value, and ECMP must deterministically choose a next hop. • Configurable Hash Algorithm • Configurable Hash Algorithm Seed • Deterministic ECMP Next Hop Configurable Hash Algorithm TeraScale has one algorithm that is used for LAGs, ECMP, and NH-ECMP, and ExaScale can use three different algorithms for each of these features. To adjust the ExaScale behavior to match TeraScale, use the following command: Task Change the ExaScale hash-algorithm for LAG, ECMP, and NH-ECMP to match TeraScale. Command Syntax hash-algorithm ecmp checksum 0 lag checksum 0 nh-ecmp checksum 0 Command Mode CONFIGURATION FTOS Behavior: In FTOS versions prior to 8.2.1.2, the ExaScale default hash-algorithm is 0. Beginning with version 8.2.1.2, the default hash-algorithm is 24. Deterministic ECMP Next Hop Deterministic ECMP Next Hop arranges all ECMPs in order before writing them into the CAM. For example, suppose the RTM learns 8 ECMPs in the order that the protocols and interfaces came up. In this case, the FIB and CAM sort them so that the ECMPs are always arranged.This implementation ensures that every chassis having the same prefixes orders the ECMPs the same. Equal Cost Multi-Path | 325