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2960 refuses to join MST region

I have configured four switches, two 3750 switches which are root for MST 1 and root for MST 2 (IPSwitch0 & IPSwitch1), the primary root is 24576 and the secondary root is 28672 plus the MST number for all three MSTs (MST 0, MST 1, and MST 2).

RaymondMoMoKahoonaHuff_1-1704001908329.png

Switch0 is a 2960 and has joined the MST region, Switch1 is configured with the same MST configuration but refuses to join the MST region. It has elected itself as the root for all three MSTs:

RaymondMoMoKahoonaHuff_2-1704002154492.png

Switch1 is not receiving any BPDUs on any of the trunk ports to IPSwitch1 or Switch0.

IPSwitch1 and Switch0 both show their directly connected ports to Switch1 are blocked because of a dispute. It is my understanding that a dispute is caused when either switch receives an inferior BPDU with the designated bit set. 

I have also tried shutting all other ports other than the link on Gi0/1 to IPSwitch0 and the results do not change. I have also removed STP features Loop Guard and Backbone Fast with the same results. 

RaymondMoMoKahoonaHuff_3-1704002692051.png

RaymondMoMoKahoonaHuff_0-1704003627592.png

RaymondMoMoKahoonaHuff_1-1704003827004.png

RaymondMoMoKahoonaHuff_2-1704003862875.png

RaymondMoMoKahoonaHuff_5-1704003396252.png

Looking forward to any suggestions

 

4 Replies 4

Hi friend can you share the config of four SW 
MHM

Would be happy to, here are the switch configs, appreciate any advice you can give me:

Friend 

First happy new year 

Now regarding your issue' the issue as I review your config is due to config defualt portfast in global mode with bpduguard.

This make port go to errdisable.

So remove portfast and bpduguard from global and config it only on port connect to host.

Check show interface status 

See which port is errdisable 

No shut these ports 

Then check mst.

MHM

Hello
suggest the following:

  • Remove ALL interface stp port-priority's and non mst vlan priority's
  • Leave all stp forward-time and max age timers to default
  • Do NOT manually prune any vlans on trunk interfaces  


Core switch 1
no spanning-tree vlan 30 priority x
no spanning-tree vlan 32 priority x
no spanning-tree vlan 30,32 forward-time x
no spanning-tree vlan 30,32 max-age x

spanning-tree mst 0,2 priority 0
spanning-tree mst 1 priority 4096

Core switch 2
no spanning-tree vlan 30 priority x
no spanning-tree vlan 32 priority x
no spanning-tree vlan 30,32 forward-time x
no spanning-tree vlan 30,32 max-age x

spanning-tree mst 0,2 priority 4096
spanning-tree mst 1 priority 0


All switch's
interface x/x
description TRUNKS
no spanning-tree vlan x port-priority x
switchport trunk allowed vlan all
spanning-tree link-type point-to-point




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Kind Regards
Paul
Review Cisco Networking for a $25 gift card