Administrator Guide

Optimizing Trac Disruption Over LAG Interfaces On IOA Switches in
VLT Mode
When you use the write memory command while an Aggregator operates in VLT mode, the VLT LAG congurations are saved in
nonvolatile storage (NVS).
By restoring the settings saved in NVS, the VLT ports come up quicker on the primary VLT node and trac disruption is reduced.
The delay in restoring the VLT LAG parameters is reduced (90 seconds by default) on the secondary VLT peer node before it
becomes operational. This makes sure that the conguration settings of the primary VLT node are synchronized with the secondary
VLT peer node before the secondary VLT mode is up. The trac outage is less than 200 millisconds during the restart or switchover
of the VLT peer nodes from primary to secondary.
Preserving LAG and Port Channel Settings in Nonvolatile Storage
Use the write memory command on an I/O Aggregator, which operates in either standalone or PMUX modes, to save the LAG
port channel conguration parameters. This behavior enables the port channels to be brought up because the congured interface
attributes are available in the system database during the booting of the device. With the reduction in time for the port channels to
become active after the switch is booted, the loss in the number of packets that are serviced by these interfaces is minimized.
Enabling the Verication of Member Links Utilization in a LAG Bundle
To examine the working eciency of the LAG bundle interfaces, perform the following steps:
1. The functionality to detect the working eciency of the LAG bundle interfaces is automatically activated on all the port
channels, except the port channel that is congured as a VLT interconnect link, during the booting of the switch.
2. Use the show link-bundle-distribution port-channel interface-number command to display the trac
handling and utilization of the member interfaces of the port channel. The following sample output is displayed when you enter
this show command.
EXEC
Dell#show link-bundle-distribution port-channel
Dell#show link-bundle-distribution port-channel 1
Link-bundle trigger threshold - 60
LAG bundle - 1 Utilization[In Percent] - 0 Alarm State - Inactive
Interface Line Protocol Utilization[In Percent]
Te 0/5 Up 0
Te 0/7 Up 0
Monitoring the Member Links of a LAG Bundle
You can examine and view the operating eciency and the trac-handling capacity of member interfaces of a LAG or port channel
bundle. This method of analyzing and tracking the number of packets processed by the member interfaces helps you manage and
distribute the packets that are handled by the LAG bundle. The functionality to detect the working eciency of the LAG bundle
interfaces is automatically activated on all the port channels, except the port channel that is congured as a VLT interconnect link,
during the booting of the switch. This functionality is supported on I/O Aggregators in PMUX, Standalone, and VLT modes. By
default, this capability is enabled on all of the port channels set up on the switch.
You can use the show link-bundle-distribution port-channel interface-number command to display the
trac-handling and utilization of the member interfaces of the port channel. The following table describes the output elds of this
show command.
120
Link Aggregation