Pvst+ Configuration; Sample Pvst+ Configuration - Dell Z9000 Configuration Manual

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2 2
Verify that the VLT LAG is up in both VLT peer units.
s4810-2#show interfaces port-channel 2 brief
Codes: L - LACP Port-channel
LAG Mode Status
L 2 L2L3 up
s4810-4#show interfaces port-channel 2 brief
Codes: L - LACP Port-channel
LAG Mode Status
L 2 L2L3 up

PVST+ Configuration

PVST+ is supported in a VLT domain.
Before you configure VLT on peer switches, configure 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. PVST+ instance will be created for every VLAN configured in the
system. PVST+ instances running in the Primary Peer will 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. PVST+ instance in Primary peer will send the
role/state of VLT-LAGs for all VLANs to the Secondary peer. Secondary peer will use this information to
program the hardware. PVST+ instance running in Secondary peer will not control the VLT-LAGs.
Dell Networking recommends configuring the primary VLT peer as the primary root device for all the
configured PVST+ Instances and configuring the secondary VLT peer as the secondary root device for all
the configured PVST+ Instances.

Sample PVST+ Configuration

The following examples show the PVST+ configuration that you must perform on each peer switch to
prevent forwarding loops.
Configure 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
Configure 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
Configure both ends of the VLT interconnect trunk with identical PVST+ configurations. 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
874
Up 1000-1199
Uptime Ports
03:43:24 Te 1/4 (Up)
Uptime Ports
03:33:31 Te 1/18 (Up)
Virtual Link Trunking (VLT)