Spaning Tree MST P2p Dispute

danhed7400 · ‎10-23-2014

hi

i have a pair of C3750X running IOS 15.2(1)E

they are connected over througt a WAN (Layer2 VPLS 802.1Q) connection.

the port on the Root Bridge is in a block state because there is a P2p Dispute. anyone got a clue to why this i happening

below is the port configuration, spanning tree configuration i have attached debug output from the Root Switch

Root Switch

spanning-tree mode mst
spanning-tree logging
spanning-tree extend system-id
spanning-tree mst 0 priority 4096

interface GigabitEthernet1/0/1
description ** xxxxxxx **
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 276-281
switchport mode trunk
storm-control broadcast level 2.00

2nd switch

spanning-tree mode mst
spanning-tree logging
spanning-tree extend system-id
spanning-tree mst 0 priority 28672

interface GigabitEthernet1/0/1
description ** xxxxx **
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 276-281
switchport mode trunk

houtan haddadlarijani · ‎10-23-2014

Hi,

The problem can be caused by STP or EtherChannel misconfiguration, or by an uni-directional link.

1- You can check the bi-directional functionality of the link or MST configuration?

2- if you configured "vlan dot1q tag native" , remove it.

Houtan

danhed7400 · ‎10-23-2014

hi.

the link is is working when i filter off BPDU, and the vlan dot1q tag native is not enabled

houtan haddadlarijani · ‎10-23-2014

Hi,

Pruning VLAN 1 can be interupting for some STP functionalities. change following link on both of your interfaces:

switchport trunk allowed vlan 1,276-281

Houtan