Users Guide
Backup RP is not supported if the VLT peer that functions as the RP is statically congured. With static RP conguration, if the RP 
reboots, it can handle new clients only after it comes back online. Until the RP returns to the active state, the VLT peer forwards the 
packets for the already logged-in clients. To enable the VLT peer node to retain the synchronized multicast routes or synchronized multicast 
outgoing interface (OIF) maps after a peer node failure, use the timeout value that you congured using the multicast peer-
routing timeout value command. You can congure an optimal time for a VLT node to retain synced multicast routes or synced 
multicast outgoing interface (OIF), after a VLT peer node failure, using the multicast peer-routing-timeout command in VLT 
DOMAIN mode. Using the bootstrap router (BSR) mechanism, you can congure both the VLT nodes in a VLT domain as the candidate RP 
for the same group range. When an RP fails, the VLT peer automatically takes over the role of the RP. This phenomenon enables resiliency 
by the PIM BSR protocol.
Conguring VLAN-Stack over VLT
To congure VLAN-stack over VLT, follow these steps.
1  Congure the VLT LAG as VLAN-Stack access or Trunk mode on both the peers.
INTERFACE PORT-CHANNEL mode
vlan-stack {access | trunk}
2  Congure VLAN as VLAN-stack compatible on both the peers.
INTERFACE VLAN mode
vlan-stack compatible
3  Add the VLT LAG as a member to the VLAN-stack on both the peers.
INTERFACE VLAN mode
member port-channel port—channel ID
4  Verify the VLAN-stack congurations.
EXEC Privilege
show running-config
Sample conguration of VLAN-stack over VLT (Peer 1)
Congure the VLT domain
Dell(conf)#vlt domain 1
Dell(conf-vlt-domain)#peer-link port-channel 1
Dell(conf-vlt-domain)#back-up destination 10.16.151.116
Dell(conf-vlt-domain)#primary-priority 100
Dell(conf-vlt-domain)#system-mac mac-address 00:00:00:11:11:11
Dell(conf-vlt-domain)#unit-id 0
Dell(conf-vlt-domain)#
Dell#show running-config vlt
!
vlt domain 1 
 peer-link port-channel 1 
 back-up destination 10.16.151.116 
 primary-priority 100 
 system-mac mac-address 00:00:00:11:11:11 
 unit-id 0
Dell#
Congure the VLT LAG as VLAN-Stack Access or Trunk Port
Dell(conf)#interface port-channel 10
Dell(conf-if-po-10)#switchport
Dell(conf-if-po-10)#vlt-peer-lag port-channel 10
Dell(conf-if-po-10)#vlan-stack access
876
Virtual Link Trunking (VLT)










