Migrating LLT links to IPv6 or dual-stack when LLT is configured over UDP using IPv4

Last published : Sep 11, 2026
To dynamically migrate from IPv4 to IPv6 configuration:
  1. Make sure that the LLT links are operational.
# lltstat -nvv configured
  1. Make sure that the IPv6 address is plumbed on all the nodes and is pingable from IPv6 interface addresses of the peer nodes.
  2. On all the nodes, add the LLT UDP link with the newly plumbed IPv6 address dynamically.
# lltconfig -t devtag -d device -b udp6 -s port [-m mtu] -I IPaddr [-B mcast] [-l] [-Q]
where,
devtag is different than the existing device tag used in llttab
device is the interface name used for the IPv6 link
  1. Verify that the UDP6 link is added properly and the links are operational.
# lltstat -l
# lltstat -nvv configured
  1. Optionally, disable and unlink the existing IPv4 link in llttab.
# lltconfig -L disable -t linkTagName
# lltconfig -u linkagName
  1. Verify whether all the high priority LLT links are now configured with IPv6 address.
lltstat -nvv configured
  1. Update llttab with the latest link configurations.
If the link configurations are not updated, the migration changes are lost after reboot or stack restart.