Setup Guide

The delay-restore feature waits for all saved configurations to be applied, then starts a configurable timer. After the timer
expires, the VLT ports are enabled one-by-one in a controlled manner. The delay between bringing up each VLT port-channel is
proportional to the number of physical members in the port-channel. The default is 90 seconds.
To change the duration of the configurable timer, use the delay-restore command.
If you enable IGMP snooping, IGMP queries are also sent out on the VLT ports at this time allowing any receivers to respond to
the queries and update the multicast table on the new node.
This delay in bringing up the VLT ports also applies when the VLTi link recovers from a failure that caused the VLT ports on the
secondary VLT peer node to be disabled.
PIM-Sparse Mode Support on VLT
The designated router functionality of the PIM Sparse-Mode multicast protocol is supported on VLT peer switches for multicast
sources and receivers that are connected to VLT ports.
VLT peer switches can act as a last-hop router for IGMP receivers and as a first-hop router for multicast sources.
Figure 132. PIM-Sparse Mode Support on VLT
On each VLAN where the VLT peer nodes act as the first hop or last hop routers, one of the VLT peer nodes is elected as the
PIM designated router. If you configured IGMP snooping along with PIM on the VLT VLANs, you must configure VLTi as the
static multicast router port on both VLT peer switches. This ensures that for first hop routers, the packets from the source are
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Virtual Link Trunking (VLT)