Preview Tool

Cisco Bug: CSCus38175 - Native VLAN Removed from Spanning-tree with 'no macro auto monitor'

Last Modified

Jan 19, 2017

Products (1)

  • Cisco Catalyst 4000 Series Switches

Known Affected Releases


Description (partial)

When applying the 'no macro auto monitor' command you will notice that all trunk interfaces go down if there are two trunked interfaces, not in a port-channel, connected from the 4500x VSS to a remote switch. The trunked interfaces go down as a result of the native VLAN being removed from Spanning-Tree.

The following output will be see when the interface goes down, after applying 'no macro auto monitor'
*Dec 22 08:07:24.635: %DTP-5-NONTRUNKPORTON: STANDBY:Port Te1/1/5,Te2/1/5 has become non-trunk

Output of show spanning-tree <native vlan> will show that vlan does no exist in spanning tree:
4500x-VSS#sho spanning-tree vlan 1

Spanning tree instance(s) for vlan 1 does not exist.

Applying the 'no macro auto monitor' command on a 4500 VSS running 3.5.X version of IOS with two trunk interfaces, not configured as a port-channel, connected to a remote switch.
Bug details contain sensitive information and therefore require a account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.