Administrator Guide

Figure 135. PIM-Sparse Mode Support on VLT
On each VLAN where the VLT peer nodes act as the rst hop or last hop routers, one of the VLT peer nodes is elected as the PIM
designated router. If you congured IGMP snooping along with PIM on the VLT VLANs, you must congure VLTi as the static
multicast router port on both VLT peer switches. This ensures that for rst hop routers, the packets from the source are redirected
to the designated router (DR) if they are incorrectly hashed. In addition to being rst-hop or last -hop routers, the peer node can also
act as an intermediate router.
The VLT peer nodes can also act as normal PIM routers on Layer 3 ports and on VLANS that do not have any VLT port members. In
addition to being rst-hop or last-hop routers, the peer node can also act as an intermediate router.
To route trac to and from the multicast source and receiver that are connected to VLT ports, enable PIM-Sparse mode on the
VLANs to which the VLT ports belong using the ip pim sparse-mode command. If IGMP Snooping is congured on these
VLANs, the VLTi must be congured as a static multicast router port on both VLT peers.
To verify the PIM neighbors on the VLT VLAN and on the multicast port, use the show ip pim neighbor, show ip igmp
snooping mrouter
, and show running config commands.
You cannot congure VLT peer nodes as rendezvous points, but you can connect PIM routers to VLT ports.
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Virtual Link Trunking (VLT)