Pvst+ Configuration; Sample Pvst+ Configuration - Dell Force10 Z9000 Configuration Manual

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
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
Name PortID
---------- -------- ---- ------
Po 1 128.2
Po 2 128.3
Te 1/10 128.230
Te 1/13 128.233
Interface
Name Role PortID
---------- ------ -------- ---- ------- ----------- ------- --------- ----
Po 1 Desg 128.2
Po 2 Desg 128.3
Te 1/10 Desg 128.230
Te 1/13 Desg 128.233
Dell#
768
Virtual Link Trunking (VLT)
Prio Cost Sts
----------- ------- -------------------- --------
128 188 FWD(vltI)
128 2000 FWD(vlt)
128 2000 FWD
128 2000 FWD
Prio Cost
128 188
128 2000
128 2000
128 2000
Designated
Cost Bridge ID
0 0
0 0
0 0
0 0
Sts Cost
FWD 0
FWD 0
FWD 0
FWD 0
PortID
90b1.1cf4.9b79 128.2
90b1.1cf4.9b79 128.3
90b1.1cf4.9b79 128.230
90b1.1cf4.9b79 128.233
Link-type Edge
(vltI)P2P No
(vlt) P2P No
P2P Yes
P2P No