CLI Guide

Table Of Contents
Virtual Link Trunking (VLT)
Virtual link trunking (VLT) allows physical links between two chassis to appear as a single virtual link to the network core. VLT
eliminates the requirement for Spanning Tree protocols by allowing link aggregation group (LAG) terminations on two separate
distribution or core switches, and by supporting a loop-free topology.
VLT provides Layer 2 multipathing, creating redundancy through increased bandwidth and enabling multiple parallel paths
between nodes and load-balancing traffic where alternative paths exist.
NOTE: When you launch the VLT link, the VLT peer-ship is not established if any of the following is TRUE:
The VLT System-MAC configured on both the VLT peers do not match.
The VLT Unit-Id configured on both the VLT peers are identical.
The VLT System-MAC or Unit-Id is configured only on one of the VLT peers.
The VLT domain ID is not the same on both peers.
If the VLT peer-ship is already established, changing the System-MAC or Unit-Id does not cause VLT peer-ship to go down.
Also, if the VLT peer-ship is already established and the VLT Unit-Id or System-MAC are configured on both peers, then
changing the CLI configurations on the VLT Unit-Id or System-MAC is rejected if any of the following become TRUE:
After making the CLI configuration change, the VLT Unit-Id becomes identical on both peers.
After making the CLI configuration change, the VLT System-MAC do not match on both peers.
When the VLT peer-ship is already established, you can remove the VLT Unit-Id or System-MAC configuration from either
or both peers. However, removing configuration settings can cause the VLT ports to go down if you configure the Unit-Id or
System-MAC on only one of the VLT peers.
Topics:
back-up destination
clear vlt statistics
delay-restore
delay-restore abort-threshold
lacp ungroup member-independent
multicast peer-routing timeout
peer-link port-channel
peer-routing
peer-routing-timeout
primary-priority
show vlt brief
show vlt backup-link
show vlt counters
show vlt detail
show vlt inconsistency
show vlt mismatch
show vlt role
show vlt statistics
show vlt statistics igmp-snoop
unit-id
vlt domain
vlt-peer-lag port-channel
61
Virtual Link Trunking (VLT) 1639