Connectivity Guide

Example configuration:
OS10(config)# vlt-domain 1
OS10(conf-vlt-1)# backup destination 10.16.151.110 vrf management interval 30
OS10(config)# vlt-domain 1
OS10(conf-vlt-1)# backup destination ipv6 1::1 vrf management interval 30
The following examples describe different cases where VLT backup link can be used:
Support for new streams during VLTi failure
When VLTi fails, MAC address learnt after the failure is not synchronized with VLT peers. This leads to continuous flooding of
traffic instead of unicast.
Due to wrong hashing, ARP learning might fail leading to traffic being dropped.
In the following illustration, after VLTi is down VLT peer1 learns MAC address of Host2.
As VLTi link fails, the VLT peer2 is not synched up with the MAC address of Host2 . Due to this, if the traffic from Host1 is
hashed to VLT peer2, then the VLT peer2 floods the traffic. Yet, the traffic would not reach Host2 as the VLT port between
VLT peer 2 and Swicth 3 is down.
When VLT backup link is enabled, the secondary VLT peer 2 identifies the node liveliness through the backup link. If the primary
is up, the secondary peer brings down the VLT LAG ports. Now the traffic from Host1 reaches VLT peer 1 and then reaches the
destination, that is Host2. In this case the traffic is unicasted instead of flooding, as shown in the following illustration.
Virtual Link Trunking
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