Users Guide

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 153. 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 redirected to the
designated router (DR) if they are incorrectly hashed. In addition to being first-hop or last -hop routers, the peer node can also act as an
intermediate router.
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Virtual Link Trunking (VLT)