is not covered in this book. Managing Spanning Tree Spanning tree is enabled by default. To see its status, use the show spanning-tree command in IOS: Cat - 3550# sho spanning-tree VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 24577 Address 0009.43b5.0f80 20 (FastEthernet0/20) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address 000f.8f5c.5a00 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 Interface Role Sts Cost Prio. Nbr Fa0/13 Altn BLK 19 128.13 Fao/14 Altn BLK 19 128.14 Fao/15 Altn BLK 19 128.15 Fa0/20 Root FWD 19 128.20 Fa0/23 Desg FWD 19 128.23 [-text removed- The bolded text shows the priority and MAC address of the root bridge, as well as what port the switch is using to get there (this is the root port). This is very useful information when you're trying to figure out where the root bridge is on a network. By running this command on every switch in the network, you should be able to map your connections and figure out which switch is the root. Managing Spanning Tree Switch-specific information is located below the root information, and below the local switch information is information specific to each port on the switch that is actively participating in spanning tree. This information will be repeated for every VLAN. In CatOS, the equivalent command is show spantree. The command produces very similar information, with a slightly different layout: Catos-6509: (enable) sho spantree VLAN 1 Spanning tree mode RAPID-PVST+ Spanning tree type Spanning tree enabled Designated Root 00-00-00-00-00-00 Designated Root Priority Designated Root Cost Designated Root Port Root Max Age o sec Hello Time 0 sec Forward Delay 0 sec Bridge ID MAC ADDR 00-00-00-00-00-00 Bridge ID Priority 32768 Bridge Max Age 20 sec Hello Time 2 Forward Delay 15 sec State Role Cost Prio Type not-connected - not-connected - not-connected - not-connected - [-text removed- Notice that the designated root MAC address is all zeros. This indicates tha