Equal Cost Multi-Path (Ecmp); Ecmp For Flow-Based Affinity; Configurable Hash Algorithm - Dell Force10 S4810P Configuration Manual

Equal Cost Multi-Path (ECMP)

Equal Cost Multi-Path (ECMP)

ECMP for Flow-based Affinity

ECMP for Flow-based Affinity
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.
Note: IPv6 /128 routes having multiple paths do not form ECMPs. The /128 route is treated as a host
entry and finds its place in the host table.
Note: Using XOR algorithms will result in imbalanced loads across an ECMP/LAG when the number of
members in said ECMP/LAG is a multiple of 4.
•

Configurable Hash Algorithm

• Configurable Hash Algorithm Seed
• Deterministic ECMP Next Hop
• Link Bundle Monitoring
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.
is supported on platforms:
is available on platforms
Command Syntax
hash-algorithm ecmp checksum 0
lag checksum 0 nh-ecmp checksum
0
e c s
e
and
Equal Cost Multi-Path (ECMP) | 397
16
Command Mode
CONFIGURATION