 all zeros. This indicates that the switch considers itself to be the root bridge. To get a summary of spanning tree, use the IOS command show spanning-tree sum mary. This command shows you the status of features like Uplink Fast and Backbonel Fast (discussed in the following section): Cat-3550#sho spanning-tree summary Switch is in pvst mode Root bridge for: VLAN0002, VLAN0200 Extended system ID is enabled Portfast Default is disabled PortFast BPDU Guard Default is disabled Portfast BPDU Filter Default is disabled Loopguard Default is disabled EtherChannel misconfig guard is enabled UplinkFast is disabled BackboneFast is disabled Configured Pathcost method used is short Blocking Listening Learning Forwarding STP Active VLAN0001 VLAN0002 VLAN0003 VLAN0004 VLAN0010 VLAN0100 VLAN0200 7 vlans Managing Spanning Tree Here is the same command as seen on a Nexus 5000: NX-5K-1# sho spanning-tree summ Switch is in rapid pvst mode Root bridge for: none Port Type Default is disable Edge Port [PortFast ] BPDU Guard Default is disabled Edge Port [PortFast] BPDU Filter Default is disabled Bridge Assurance is enabled Loopguard Default is disabled Pathcost method used is short Blocking Listening Learning Forwarding STP Active VLAN0001 VLAN0100 2 vlans In CatOS, the summary command is show spantree summary: Catos-6509: (enable)sho spantree summ Spanning tree mode: RAPID-PVST+ - Runtime MAC address reduction: disabled Configured MAC address reduction: disabled Root switch for vlans: 20. Global loopguard is disabled on the switch. Global portfast is disabled on the switch. BPDU skewing detection disabled for the bridge. BPDU skewed for vlans: none. Portfast bpdu-guard disabled for bridge. Portfast bpdu-filter disabled for bridge. Uplinkfast disabled for bridge. Backbonefast disabled for bridge. Summary of connected spanning tree ports by vlan VLAN Blocking Listening Learning Forwarding STP Active Blocking Listening Learning Forwarding STP Active Total An excellent command in IOS is show spanning-tree root, which shows you the in- f