Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
You may experience some slow load times, errors, and slight inconsistencies. We ask for your patience as we finalize the launch. Thank you.

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

STP

Hi,

does each root bridge mac address of each vlan which created on a single core switch the same? What will cause an access switch to lose 3x BPDU from the core with a direct connection?

thanks!

  • Other Network Infrastructure Subjects
3 REPLIES
VIP Purple

Re: STP

Hello,

I do not understand the first part of your question, but regarding the loss of BPDU packets, the reason could be excessive collisions and subsequent packet loss, possibly because of a duplex mismatch. You might want to check this document, I think you need a CCO logon to view it:

Troubleshooting Spanning-Tree Protocol and Related Design Considerations

http://www.okena.com/en/US/partner/tech/tk389/tk621/technologies_tech_note09186a00800951ac.shtml

Regards,

Georg

Bronze

Re: STP

in a per vlan spanning tree environment, each spanning tree instance (vlan) will have a different root bridge mac address. If you find that the root bridge mac address is the same for a couple of vlans then these vlans have been bridged. This can result in a bridging loop. Unfortunately I do not understand the 2nd question.

New Member

Re: STP

hi there,

the access switch is directly connected to a core switch, however, during the day, there were a few instance that the access switch loses the BPDU causes the access switch to max-time out. And the STP re-calculate again!...thanks!

126
Views
0
Helpful
3
Replies