NX-OS spanning tree timer

[adfsdafs adsfafds]

From the command reference example

switch# show spanning-tree detail

VLAN0001 is executing the rstp compatible Spanning Tree protocol

Bridge Identifier has priority 32768, sysid 1, address 0005.9b23.407c

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

We are the root of the spanning tree

Topology change flag not set, detected flag not set

Number of topology changes 0 last change occurred 663:31:38 ago

Times: hold 1, topology change 35, notification 2

hello 2, max age 20, forward delay 15

Timers: hello 0, topology change 0, notification 0

What is Timers for?

I assume Times is rstp timer, what is topology change 35s, notification 2s used for?

[Mark Malone]

topology change  is the amount of times the interface has seen an STP change and being part of a recalculation at layer 2

a better command for viewing changes and tracing them when the occur in stp ------sh spanning-tree det | i ieee|occur|from|is exec 

[adfsdafs adsfafds]

Thanks. How come Number of topology changes 0? Is there a bug in NX-OS with the topology change counter and timer?

On real N5k that number makes no sense (claiming topology change a few hours ago but nothing in counter or spanning tree log indicates topology change happened)

[Mark Malone]

don't know why its 0 where did you get that output ? looking at all mine you can see the counter increasing in number of topology changes below as example   , the tcn 35 is the max age + the forward delay timer

 VLAN0038 is executing the rstp compatible Spanning Tree protocol
  Bridge Identifier has priority 24576, sysid 38, address x.x.x
  Configured hello time 2, max age 20, forward delay 15
  We are the root of the spanning tree
  Topology change flag not set, detected flag not set
  Number of topology changes 27 last change occurred 118:47:25 ago
          from port-channel1
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
  Timers: hello 0, topology change 0, notification 0