Spanning Tree Issue Root in BKN*4 State

[leyakhath muhammed]

I have 2960 S switch , port blinking orange light on the port (gig1/0/8) 

When I run the command, show spanning-tree [in 2960 S] ,I found the following result:

VLAN0004

  Spanning tree enabled protocol ieee

  Root ID    Priority    32768

             Address     d067.e5cc.2dc0

             Cost        8

             Port        24 (GigabitEthernet1/0/24)

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32772  (priority 32768 sys-id-ext 4)

             Address     b4e9.b005.1d80

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Gi1/0/2             Desg FWD 4         128.2    P2p Edge

Gi1/0/5             Desg FWD 4         128.5    P2p Edge

Gi1/0/6             Desg FWD 19        128.6    P2p Edge

Gi1/0/7             Desg FWD 19        128.7    P2p Edge

Gi1/0/8             Desg BKN*4         128.8    P2p *TYPE_Inc

Gi1/0/22            Desg FWD 4         128.22   P2p

Gi1/0/23            Desg FWD 4         128.23   P2p

Port 8 (GigabitEthernet1/0/8) of VLAN0004 is broken  (Port Type Inconsistent)

   Port path cost 4, Port priority 128, Port Identifier 128.8.

   Designated root has priority 32768, address d067.

   Designated bridge has priority 32772, address b4e9.

   Designated port id is 128.8, designated path cost 8

   Timers: message age 0, forward delay 13, hold 0

   Number of transitions to forwarding state: 3

   Link type is point-to-point by default

   BPDU: sent 13204055, received 13205071

%SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk GigabitEthernet1/0/8 VLAN4.

 %SPANTREE-7-BLOCK_PORT_TYPE: Blocking GigabitEthernet1/0/8 on VLAN0004. Inconsistent port type

Thanks

[RabbitSchpaenningtri]

I've seen this behavior after upgrading NX-OS from major version 6 to 7. It seem like RPVST+ lost its downward compatibility to PVST+. Enabling RPVST+ on the older machines solved the Problem. You can check the version of spanning tree by running #show spanning-tree summary on both sides of the broken link.

[Bader Saleh]

I received the same error on GNS3 and this is because one side was configure as trunk nonegotiate and the other was DTP auto after change it to nonegotiate and put the same encapsulation as other switch it's fixed the problem ,note the error received on the DTP auto switch 

hope this fix your issue

[Zalameen]

This indicates a port configuration mismatch between 2 switches and a common issue is trunk vs access port mode.