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 dierent hash result for every
chassis. This behavior means that for a given ow, even though the prexes are sorted, two unrelated chassis
select dierent hops.
Dell provides a CLI-based solution for modifying the hash seed to ensure that on each congured system, the
ECMP selection is same. When congured, the same seed is set for ECMP, LAG, and NH, and is used for incoming
trac 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 dierent 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 conguration 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 congured,
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-specic. 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