Reference Guide

To configure the hash algorithm seed, use the following command.
● Specify the hash algorithm seed.
CONFIGURATION mode.
hash-algorithm seed value [linecard slot-id] [port-set number]
The range is from 0 to 4095.
Link Bundle Monitoring
Link bundle monitoring allows the system to monitor the use of multiple links for an uneven distribution.
A global default threshold of 60% is the usage percentage for the bundle; when the system reaches this threshold, it begins
monitoring the configured ECMP groups for uneven distribution. Links are monitored in 15-second intervals for three
consecutive instances. Any deviation exceeding 10% among any of the bundle links sends a syslog and an alarm event is
generated; for example, 01:16:25: %STKUNIT0-M:CP %IFMGR-5-BUNDLE_UNEVEN_DISTRIBUTION: Found uneven
distribution in ECMP-GROUP bundle 1.
When the deviation clears, another syslog is sent and a clear alarm event is generated; for example, 01:35:14: %STKUNIT0-
M:CP %IFMGR-5-BUNDLE_UNEVEN_DISTRIBUTION_ALARM_CLEAR: Uneven distribution in ECMP-GROUP
bundle 1 got cleared.
The link bundle utilization is calculated as the total bandwidth of all links divided by the total bytes-per-second of all links, as
shown in the following example.
Example of Viewing Link Bundle Monitoring
Dell# show link-bundle-distribution ecmp-group 1
Link-bundle trigger threshold - 60
ECMP bundle - 1 Utilization[In Percent] - 44 Alarm State - Active
Interface Line Protocol Utilization[In Percent]
Te 0/0 Up 36
Te 0/1 Up 52
Managing ECMP Group Paths
To manage ECMP group paths, you can 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
Dell(conf)#ip ecmp-group maximum-paths 3
User configuration has been changed. Save the configuration and reload to take effect
Dell(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%.
Equal Cost Multi-Path (ECMP)
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