Administrator Guide

Parameters
seed value Enter the keyword seed then the seed value. The range is from 0 to 4095.
linecard slot Enter the keyword linecard then the linecard slot number.
port-set number Enter the keyword port-set then the linecard port-pipe number.
Defaults 32–bit Chassis MAC
Command Modes CONFIGURATION
Command
History
This guide is platform-specific. For command information about other platforms, see the relevant Dell
Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.9(0.0) Introduced on the C9010.
9.2(1.0) Introduced on the Z9500.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.7.0 Introduced on the S4810.
8.3.1.0 Introduced on the E-Series.
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 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.
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.
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.
C9000 Series
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
Equal Cost Multi-Path (ECMP) 653