RSTP (802.1w)
Configuring RSTP is as easy as it is for any of the other 802.1d extensions. Considering
how much better it is than 802.1d, you’d think the configuration would be more complex, but
you’re in luck—it’s not. So let’s turn in on the Core switch now and see what happens:
Core#config t
Core(config)#spanning-tree mode ?
mst Multiple spanning tree mode
pvst Per-Vlan spanning tree mode
rapid-pvst Per-Vlan rapid spanning tree mode
Core(config)#spanning-tree mode rapid-pvst
Core(config)#
1d02h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
1d02h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
Sweet! The Core switch is now running the 802.1w STP. Let’s verify that:
Core#show spanning-tree
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 32769
Address 000d.29bd.4b80
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 000d.29bd.4b80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- ------------
Fa0/5 Desg FWD 19 128.5 P2p Peer(STP)
Fa0/6 Desg FWD 19 128.6 P2p Peer(STP)
Fa0/7 Desg FWD 19 128.7 P2p Peer(STP)
Fa0/8 Desg FWD 19 128.8 P2p Peer(STP)