|
slinkydtd
1 post
 |
We have a VLAN which is trunked across multiple switches in our network. While troubleshooting a problem on that network, I found that there are two switches that think they are the root bridge for that particular VLAN. The switch that we prefer to be the root has previously been configured with the 'spanning-tree vlan xxx priority 8192' command, so it should be the root. I have also gone back and checked, and I am fairly certain that the VLAN is properly trunked all the way through between the two switches. Has anyone seen this before, and does anyone know the proper way to resolve it with the least amount of impact to the users and other networks on the switches? Thanks for your help. |
|
stretch
258 posts
 |
It would seem that the VLAN is not contiguous between the two switches. Can they communicate with one another within that VLAN? Also check for any intermediary devices which may be discarding BPDUs. |
|
discovery29
1 post
|
The original post was not mine, but your suggestion is helped a lot. Thanks for the suggestion. I'm also seeing two root bridges for VLAN 1, so does this has no impact on network.?? How does STP work in this situations?? |
|
mkomon
22 posts
 |
Two root bridges (RBs) in a VLAN means it is probably not properly trunked thoughout the LAN and the two RBs are isolated from each other. Or, as Jeremy has noticed, there might be a device between the two RBs eating your BPDUs. In a situation like this, probably with two isolated parts of the network, STP runs independently in each one of them. Make sure your VLAN goes where it should, that it connects both RBs and you can also try if the RBs can communicate with each other in that particular VLAN. |
Viewing 1 - 4 of 4
- 1