STP recalculation

[rsamuel708]

Are there any commands to show the last time STP recalculated? I'm pretty certain that you can't see this in the logs. Correct?

/rls

[mohammedmahmoud]

Hi,

To check the last time a topology change has occurred then please use "show spanning-tree vlan x detail":

Rack1SW1#sh spanning-tree vlan 1 detail

VLAN0001 is executing the ieee compatible Spanning Tree protocol

Bridge Identifier has priority 32768, sysid 1, address 001b.90b4.6900

Configured hello time 2, max age 20, forward delay 15

Current root has priority 32769, address 001b.904f.ec00

Root port is 15 (FastEthernet0/13), cost of root path is 19

Topology change flag not set, detected flag not set

Number of topology changes 15 last change occurred 00:00:55 ago from FastEthernet0/1

Times: hold 1, topology change 35, notification 2

hello 2, max age 20, forward delay 15

Timers: hello 0, topology change 0, notification 0, aging 300

BR,

Mohammed Mahmoud.

[rsamuel708]

Can you tell me what version of code did the number of topology changes including the last change time begin? I have a 3550 running the following code and it gives me the following output:

Cisco Internetwork Operating System Software

IOS (tm) C3500XL Software (C3500XL-C3H2S-M), Version 12.0(5.4)WC(1), MAINTENANCE INTERIM SOFTWARE

switch#sho span vlan 1 det

^

% Invalid input detected at '^' marker.

Thanks.

/rls

[mohammedmahmoud]

Hi,

The output i've posted is from a 3560 running "c3560-advipservicesk9-mz.122-25.SEE3.bin", i've tried this on one of my 3500XL and yes it seems that it doesn't support this command, you can try and do an IOS upgrade, but i can't assure you that it will support this command.

BR,

Mohammed Mahmoud.