SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet2/0/6 on VLAN777

[damjorn2023]

Hi guys, 

Can anyone help me. I have issue with the following logs.

%LINK-3-UPDOWN: Interface GigabitEthernet2/0/6, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet2/0/6, changed state to up

%SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet2/0/6 on VLAN0777. Inconsistent local vlan.

%LINK-3-UPDOWN: Interface GigabitEthernet1/0/2, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/2, changed state to up

before I connected link from ISP router to my edge router by configure trunk encapsulation dot1q on both end, but now I plan to connect from ISP router to my switch and then from switch to edge router. on my edge router connect to switch I configure subinterface, on switch ports connect to edge router and ISP router configure as trunk and ISP router configure trunk. see the bellow config:

+ switch

interface GigabitEthernet1/0/2
description connect to edge router Gi0/0/2.777
switchport trunk allowed vlan 666,777
switchport mode trunk

+ edge router

interface GigabitEthernet0/0/2.777
encapsulation dot1Q 777
ip address x.x.x.x x.x.x.x

+ ISP router

interface GigabitEthernet0/0/3.777
encapsulation dot1Q 777
ip address x.x.x.x x.x.x.x

Is it possible to configure like this topology? If possible how can I eliminate bellow blocking port?

%SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet2/0/6 on VLAN0777. Inconsistent local vlan.

thank.

[marce1000]

 - Use of STP between edge router and ISP is not advised  because you are jumping into another  unknown 'layer 2 domain' ;  layer 3 connectivity with the ISP  is much more stable and reliable.

 M.

[damjorn2023]

You mean need to apply STP on switch ports connect to edge and ISP router? this is DPLC link use to connect to other site.

[pieterh]

you post configuration for anything BUT GigabitEthernet2/0/6 !
>>> Inconsistent local vlan  <<
-> you probably need to add the untagged vlan from the ISP to your switchport
e.g.
    switchport trunk allowed vlan 1,666,777
(where vlan 1 is the default/untagged vlan)

[damjorn2023]

thank for your replied, I'll try this. 

[MHM Cisco World]

Are you run different stp mode in each SW?

[damjorn2023]

the other site is ISP router configure with subinterface trunk encapsulation to my switch with default stp.

[MHM Cisco World]

ISP-trunk-SW-edge router 

If SW is connect to l3 device then there is no should any l2 loop and there is no any needing to STP.

But I think ISP or edge router is from other vendor not Cisco and run STP and your SW run PVST and hence the stp error come from.

Can I see show spanning tree in SW 

[damjorn2023]

Yes my switch is connected to ISP router and it is DPLC link, My both local devices are model Cisco and ISP router is Juniper model.

[MHM Cisco World]

Can you try use access not trunk between SW and ISP.

This make ISP send one bpdu and SW understand it even if it use pvst.

Again can i see show spanning of SW

[damjorn2023]

Can you try use access not trunk between SW and ISP. -> It is under ISP I can't do anything on router ISP and old topology is connect from router to router configure trunk encapsulation dot1q.

Again can i see show spanning of SW. -> I have rollback already can't show.

[MHM Cisco World]

Juniper must run RSTP and VSTP for any interface connect to cisco SW.

Or run MST on Cisco 

Check juniper and cisco stp compatibility.

[damjorn2023]

Thank for your kind support. let me check on that.

[paul driver]

Hello

---

@damjorn2023 wrote:

on my edge router connect to switch I configure subinterface

---

Make sure your core switch is the stp root for all vlans in the estate and the native vlan is consistent between switch interconnects- the above error log suggests you could have either and stp mode mismatch between the two switches( say pvst and cst like 802.1d )
so when a pvst bpdu for vlan777 is received on the 802.1d port it isnt recognised as the other switch only knows and cares about a single bpdu for all vlans (cst)  or the native vlan on either side of the switch doesn’t have parity 

[damjorn2023]

So, could I know how to set my switch as the stp root? what's the 802.1d and how to prevent pvst bpdu for vlan777 is received on the 802.1d port? 

based on my topology and configuration, could you advice configuration to eliminate this log error?