Administrator Guide

Link Bundle Monitoring
Monitoring linked ECMP bundles allows traffic distribution amounts in a link to be monitored for unfair
distribution at any given time.
A threshold of 60% is defined as an acceptable amount of traffic on a member link. Links are monitored in 15-
second intervals for three consecutive instances. Any deviation within that time causes a syslog to be sent and
an alarm event to be generated. When the deviation clears, another syslog is sent and a clear alarm event is
generated.
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, you can specify interfaces. If you enable monitoring 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 you
configure 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.
To enable the link bundle monitoring feature, for link bundle monitoring with ECMP, use the ecmp-group
command.
You can configure the ecmp-group with id 2, enabled for link bundle monitoring. 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
Equal Cost Multi-Path (ECMP) 324