Users Guide

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Virtual Link Trunking (VLT)
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 trac 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 congured on both the VLT peers do not match.
• The VLT Unit-Id congured on both the VLT peers are identical.
• The VLT System-MAC or Unit-Id is congured 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 congured on both peers, then
changing the CLI congurations on the VLT Unit-Id or System-MAC is rejected if any of the following become TRUE:
• After making the CLI conguration change, the VLT Unit-Id becomes identical on both peers.
• After making the CLI conguration 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 conguration from either or
both peers. However, removing conguration settings can cause the VLT ports to go down if you congure the Unit-Id or
System-MAC on only one of the VLT peers.
back-up destination
Congure the IPv4 or IPv6 address of the management interface on the remote VLT peer to be used as the endpoint of the VLT
backup link for sending out-of-band hello messages.
Syntax
back-up destination {[ipv4–address] | [ipv6 ipv6–address] [interval
seconds]}
Parameters
ipv4–address Enter the IPv4 address of the backup destination.
ipv6 Enter the keyword ipv6 then an IPv6 address in the X:X:X:X::X format.
interval seconds Enter the keyword interval to specify the time interval to send hello messages.
The range is from 1 to 5 seconds. The default is 1 second.
Defaults 1 second
Command Modes VLT DOMAIN
Supported Modes Programmable-Mux (PMUX)
Virtual Link Trunking (VLT)
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