Users Guide

Multicast peer-routing timeout : 150 seconds
Dell#
Verify that the VLT LAG is up in VLT peer unit.
Dell-2#show interfaces port-channel 2 brief
Codes: L - LACP Port-channel
LAG Mode Status Uptime Ports
L 2 L2L3 up 03:43:24 Te 1/1/4/1 (Up)
Dell-4#show interfaces port-channel 2 brief
Codes: L - LACP Port-channel
LAG Mode Status Uptime Ports
L 2 L2L3 up 03:33:31 Te 1/1/5/1 (Up)
PVST+ Conguration
PVST+ is supported in a VLT domain.
Before you congure VLT on peer switches, congure PVST+ in the network. PVST+ is required for initial loop prevention during the VLT
startup phase. You may also use PVST+ for loop prevention in the network outside of the VLT port channel.
Run PVST+ on both VLT peer switches. A PVST+ instance is created for every VLAN congured in the system. PVST+ instances running in
the Primary Peer control the VLT-LAGs on both Primary and Secondary peers. Only the Primary VLT switch determines the PVST+ roles
and states on VLT ports and ensures that the VLT interconnect link is never blocked. The PVST+ instance in Primary peer sends the role/
state of VLT-LAGs for all VLANs to the Secondary peer. The Secondary peer uses this information to program the hardware. The PVST+
instance running in Secondary peer does not control the VLT-LAGs.
Dell Networking recommends conguring the primary VLT peer as the primary root device for all the congured PVST+ Instances and
conguring the secondary VLT peer as the secondary root device for all the congured PVST+ Instances.
Sample PVST+ Conguration
The following examples show the PVST+ conguration that you must perform on each peer switch to prevent forwarding loops.
Congure PVST+ on VLT Peers to Prevent Forwarding Loops (VLT Peer 1)
Dell_VLTpeer1(conf)#protocol spanning-tree pvst
Dell_VLTpeer1(conf-pvst)#no disable
Dell_VLTpeer1(conf-pvst)#vlan 1000 bridge-priority 0
Congure PVST+ on VLT Peers to Prevent Forwarding Loops (VLT Peer 2)
Dell_VLTpeer2(conf)#protocol spanning-tree pvst
Dell_VLTpeer2(conf-pvst)#no disable
Dell_VLTpeer2(conf-pvst)#vlan 1000 bridge-priority 4096
Congure both ends of the VLT interconnect trunk with identical PVST+ congurations. When you enable VLT, the show spanning-
tree pvst brief
command output displays VLT information.
Dell#show spanning-tree pvst vlan 1000 brief
VLAN 1000
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 0, Address 90b1.1cf4.9b79
Root Bridge hello time 2, max age 20, forward delay 15
Bridge ID Priority 0, Address 90b1.1cf4.9b79
We are the root of Vlan 1000
Configured hello time 2, max age 20, forward delay 15
Interface Designated
Name PortID Prio Cost Sts Cost Bridge ID PortID
---------- -------- ---- ------ ----------- ------- -------------------- --------
Po 1 128.2 128 188
FWD(vltI) 0 0 90b1.1cf4.9b79 128.2
Po 2 128.3 128 2000 FWD(vlt) 0 0 90b1.1cf4.9b79 128.3
858
Virtual Link Trunking (VLT)