Reference Guide

Table Of Contents
The link bundle utilization is calculated as the total bandwidth of all links divided by the total bytes-per-
second of all links. Within each ECMP group, interfaces can be specified. If monitoring is enabled for the
ECMP group, the utilization calculation is performed when the utilization of the link-bundle (not a link
within a bundle) exceeds 60%.
Enable link bundle monitoring using the ecmp-group command.
NOTE: An ecmp-group index is generated automatically for each unique ecmp-group when the
user configures multipath routes to the same network. The system can generate a maximum of 512
unique ecmp-groups. The ecmp-group indexes are generated in even numbers (0, 2, 4, 6... 1022)
and are for information only.
For link bundle monitoring with ECMP, the ecmp-group command is used to enable the link bundle
monitoring feature. The ecmp-group with id 2, enabled for link bundle monitoring is user configured.
This is different from the ecmp-group index 2 that is created by configuring routes and is automatically
generated.
These two ecmp-groups are not related in any way.
Managing ECMP Group Paths
Configure the maximum number of paths for an ECMP route that the L3 CAM can hold to avoid path
degeneration. When you do not configure the maximum number of routes, the CAM can hold a
maximum ECMP per route.
To configure the maximum number of paths, use the following command.
NOTE: Save the new ECMP settings to the startup-config (write-mem) then reload the system for
the new settings to take effect.
Configure the maximum number of paths per ECMP group.
CONFIGURATION mode.
ip ecmp-group maximum-paths {2-64}
Enable ECMP group path management.
CONFIGURATION mode.
ip ecmp-group path-fallback
Example of the ip ecmp-group maximum-paths Command
pt-s5000-temp1(conf)#ip ecmp-group maximum-paths 3
User configuration has been changed. Save the configuration and reload to take
effect
pt-s5000-temp1(conf)#
Creating an ECMP Group Bundle
Within each ECMP group, you can specify an interface.
If you enable monitoring for the ECMP group, the utilization calculation is performed when the average
utilization of the link-bundle (as opposed to a single link within the bundle) exceeds 60%.
1. Create a user-defined ECMP group bundle.
CONFIGURATION mode
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Equal Cost Multi-Path (ECMP)