Cisco 4500M Command Reference Manual page 101

Chapter2 Cisco IOS Commands for the Catalyst 4500 Series Switches
Examples
This example shows how to enable transmit BPDU debugging on the spanning tree switch shim:
Switch# debug spanning-tree switch tx
Spanning Tree Switch Shim transmit bpdu debugging is on
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 303
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 304
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 305
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 349
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 350
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 351
*Sep 30 08:47:33: SP: STP SW: TX: bpdu of type ieee-st size 92 on FastEthernet5/9 801
<... output truncated...>
Switch#
Related Commands
undebug spanning-tree switch (same as no debug spanning-tree switch)
78-16201-01
Catalyst4500 Series SwitchCiscoIOS Command Reference—Release 12.2(18)EW
debug spanning-tree switch
2-69