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 none
Command
Modes
CONFIGURATION
Command
History
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.
Version
8.3.19.0
Introduced on the S4820T.
Version 8.3.11.1 Introduced on the Z9000.
Version 8.3.7.0 Introduced on the S4810.
Version 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.
FTOS 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.
Equal Cost Multi-Path (ECMP)
551