Example 127 Viewing Spanning Tree for VLAN

yin#show spanning-tree


Spanning tree enabled protocol ieee Root ID Priority 32768 <<<text omitted>>> VLAN0 0 02

Spanning tree enabled protocol ieee

Root ID Priority Address



0004.275e.f0c7 3

65 (Port-channell) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32770 (priority 32768 sys-id-ext 2) Address 0 0 0a.8a0e.ba8 0

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300

Interfa ce Port ID Designated Port ID

Name Prio.Nbr Cost Sts Cost Bridge ID Prio.Nbr






19 FWD 19 FWD 3 FWD

3 32770 000a.8a0e.ba80 128.3 3 32770 000a.8a0e.ba80 128.16 0 100 0004.275e.f0c7 128.1

Every bit of information provided by this command is useful. The fields are defined as follows:

• Spanning tree type— The type of Spanning Tree Protocol in use: IBM, DEC, or IEEE.

• Root ID Priorit y— The bri dge priority that was received from the root bridge. The values of -priority range from 0 to 65,535, with 32,768 as the default.

• Root ID Cost— The cumulative cost to the root bridge.

• Root ID Port— The root port for that segment.

• Root Max Age, Hello Time, Forward Delay— The three STP timers as sent by the root brid

• Bridge ID MAC ADDR— The MAC address that is being used for this VLAN by this local bridg i Bridge ID P riority— The priority of she local bridge.

• Bridge Max Age , Hello Time, Forward Delay— The thaee STP timers on th e loc al bridge.

The finnl rows show each port that is participatin g in STP winhi n ehe VLAN and l • sts whether the poi forwarding or blocking, as well as the cost and service priority of the port. Do not confuse this prio spannrng-tree br idge briori ty. Thevalues oftohre port priority range fro m 0 to 633, w ith 32 as the def

Another com mand that is useful in presenting a general o eefationaI picture of epanmng tree is the spantree pu mimacy comma nde Thio c ommand provider a h overview of the VLANs and the state of an STP pefsee<f:iva. Exa mble 1-28 ests the outpct for this commaad.

0 0

Post a comment