MST Issue

Unanswered Question
Aug 18th, 2009
User Badges:

Dear Friends,

I hv an issue with MST on 3550 switches, i have connected three 3550 swithces in a triangle topology..sw1->sw2->sw3->sw1. sw1 is the root bridge for vlan 10 - 60 but when i configured sw2 and sw3 as MST now sw2 becomes the root bridge even though it's BID is larger than sw1 (Root Bridge)

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Peter Paluch Tue, 08/18/2009 - 10:57
User Badges:
  • Cisco Employee,


Is the MST configured properly on all switches, i.e., is the number of MST instances, individual VLAN mappings, region name and the revision number identical on all switches?

Also please note that for MST, the priority is configured using the command spanning-tree mst INSTANCE priority PRIORITY, not the usual "spanning-tree vlan X priority N".

Best regards,



This Discussion