01-20-2015 10:22 AM
Hi guys, I am trying to troubleshoot an issue that happened on our enterprise network. I keep seeing these messages logged on switch stacks:
Jan 20 10:03:17:I:STP: VLAN 22 New RootBridge: 700008eb74adbc1a RootPort: 4/1/47 (BpduRcvd)
Jan 20 10:03:17:I:STP: VLAN 22 New RootPort: 4/1/47 (RootSelection)
Jan 20 10:03:17:I:STP: VLAN 22 Bridge is RootBridge: 8000cc4e2465f440 (MsgAgeExpiry)
Sometimes it floods the log buffer with 20+ entries. The mac address 08eb74adbc1a is a directTV set top box. I know there are things like stp-protect and root guard enable on the switch, but I would like to understand a little bit more about what may be going on. Has anyone encountered this before?
01-21-2015 01:50 PM - edited 01-21-2015 01:56 PM
Proper spanning tree configuration is critical to the stability and performance of any network.
At a minimum the following parameters should be configured:
1. You should be enabling "spanning-tree 802-1w" on each vlan.
2. Classifying each edge port as either "spanning-tree 802-1w admin-edge-port" or "spanning-tree 802-1w admin-pt2pt-mac"
3. Enable "stp-bpdu-guard" on each edge port. Spanning tree BPDUs should only be exchanged between devices you want to participate in spanning tree, not your direct tv box.
What version of code are you using? Is this part of a stack or mixed family stack?
You should also set the "spanning-tree 802-1w priority" to designate which switch you want to be the root bridge of that vlan.
As always, if you're product is still under the 3 years of phone support and your'e the original purchaser of the equipment, TAC can help you troubleshoot this further.
TAC can be reached at 1-800-752-8061.