Administrator Guide

Usage Information 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 dierent hash result for every
chassis. This behavior means that for a given ow, even though the prexes are sorted, two unrelated chassis
select dierent hops.
Dell provides a CLI-based solution for modifying the hash seed to ensure that on each congured system, the
ECMP selection is same. When congured, the same seed is set for ECMP, LAG, and NH, and is used for incoming
trac only.
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 dierent 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 conguration is removed, the hash seed does not go to the original factory default
setting.
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 congured,
the CAM can hold a maximum of 16 ecmp per route.
Syntax
ip ecmp-group {maximum-paths | {number} {path-fallback}
To negate a command, use the no ip ecmp-group maximum-paths {number} command.
Parameters
maximum-paths Specify the maximum number of ECMP for a route. The range is 2 to 64.
path-fallback Use the keywords path-fallback to enable this feature. If you enable the feature, re-
enter this keyword to disable the feature.
Defaults 16
Command Modes CONFIGURATION
Command History
This guide is platform-specic. For command information about other platforms, see the relevant Dell Networking
OS Command Line Reference Guide.
Version Description
9.8(1.0) Introduced on the Z9100–ON.
9.8(0.0P5) Introduced on the S4048-ON.
9.8(0.0P2) Introduced on the S3048-ON.
9.7(0.0) Introduced on the S6000-ON.
9.2(1.0) Introduced on the Z9500.
9.0.2.0 Introduced on the S6000.
9.0.0.0 Introduced on the Z9000.
Equal Cost Multi-Path (ECMP) 555