Ip Ecmp-Group - Dell Z9500 Reference Manual

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CONFIGURATION

This guide is platform-specific. For command information about other platforms,

refer to the relevant Dell Networking OS Command Line Reference Guide.

The following is a list of the Dell Networking OS version history for this command.

Deterministic ECMP sorts ECMPs in order even though RTM provides them in a

random order. However, the hash algorithm uses as a seed the lower 12 bits of the

chassis MAC, which yields a different hash result for every chassis. This behavior

means that for a given flow, even though the prefixes are sorted, two unrelated

chassis select different hops.

The system provides a CLI-based solution for modifying the hash seed to ensure

that on each configured system, the ECMP selection is same. When configured, the

same seed is set for ECMP, LAG, and NH, and is used for incoming traffic only.

ip ecmp-group

Enable and specify the maximum number of ecmp that the L3 CAM hold for a route, By default, when

maximum paths are not configured, the CAM can hold a maximum of 16 ecmp per route.

ip ecmp-group {maximum-paths | {number} {path-fallback}

Equal Cost Multi-Path (ECMP)

Introduced on the Z9500.

Introduced on the S4820T.

Introduced on the Z9000.

Introduced on the S4810.

Introduced on the E-Series.

NOTE: While the seed is stored separately on each port-pipe, the same seed is

used across all CAMs.

You cannot separate LAG and ECMP but you can use different algorithms

across the chassis with the same seed. If LAG member ports span multiple

port-pipes and line cards, set the seed to the same value on each port-pipe to

achieve deterministic behavior.

If the hash algorithm configuration is removed, the hash seed does not go to

the original factory default setting.