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pvst inconsistent vlan, rstp interopability

David.Spencer
Beginner
Beginner

My configuration is as follows, indicating the native vlan on each trunk interface:

2020-08-18_09h59_54.png

the native vlans are fully tagged across these trunks (except 1003).

 

when I connect the cisco 9300 across the wireless mesh, I get a PVST vlan mismatch error at my router, disabling vlan 1 and vlan 2527. disconnecting the switch but leaving the wirelss mesh up via poe injector, everything works fine.

 

This cisco switches are running PVST, and the avaya switches are running RSTP. I have rstp disbaled on the trunk ports.

 

I'm using vlan 1003 at the router native to the distribution as I want vlan 1 tagged (avaya tags the native vlan, which we need vlan 1 for mgmt. i'm migrating away from this). chose 1003 as I know I wont be using it because of the cisco reservation.

 

I'm not sure why I'm getting the mismatch error. all the native vlans except 1003 should be fully tagged across these trunks.

 

4 Replies 4

balaji.bandi
VIP Guru VIP Guru
VIP Guru

its odd, not sure how aruba behave ( or show any logs on the device)

 

what happends when you change all native vlan 1 ? also check all the VLAN allowed same as other side ?

 

 

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I found on the switch connection to the wireless mesh portal it did not have vlan 1 tagged. unsure if this is the culprit or something else as well.

 

It appears that even though only vlan 1 and 2527 were blocked, it affected all connections on ths core to distribution port channel as reported by operations.

 

Here are the logs from the router:

%SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel7 on VLAN0001. Inconsistent peer vlan.
%SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel7 on VLAN2527. Inconsistent local vlan.

 

I'm not keen on changin the native vlan to 1 while we are operating. I know the avaya switches require their management network to be tagged and set as native vlan on the trunk to be accessible.

Matt Delony
Cisco Employee
Cisco Employee

Hello David.Spencer,

 

PVID inconsistency occurs when the BPDU is received on different vlan than where it originated. The most common scenario would be native vlan mismatch on a trunk, but it can happen in other situations.

 

A PVST BPDU has a TLV for originating VLAN (PVID). This TLV will list the VLAN where the BPDU originated.

 

Is there any chance that the BPDU arriving at the router has a PVID of VLAN 2527, but has an 802.1q tag for VLAN 1?

Hi Matt,

I foudn the avaya switch was missing vlan 1 on the connection to the Aruba AP, I've not tested since adding this, but can't attempt the connection during production. as vlan 1 was not the native vlan for either end of the trunk, I don't think this would have caused the issue.

When I place a nortel 450 switch at the location of the 9300, it does not cause this issue. however the nortel 450 tags the pvid by default, which I have not performed on the 9300. The avaya swtiches also tag pvid by default.

Here is the config of the trunk interface on the 9300 to the aruba AP.

interface GigabitEthernet1/0/2
description Mesh to offices
switchport mode trunk
switchport trunk allow vlan none
switchport trunk native vlan 2527
switchport trunk allowed vlan add 1,908,909,2360,2507,2527,3407
no shut
exit

avaya switch with AP downlink

A07-20CA-DSPCMainOffices#show interface 30 config
Port: 30
Trunk:
Admin Status: Enable
Oper Status: Up
EAP Oper Status: Up
VLACP Oper Status: Down
STP Oper Status: Forwarding
Link: Up
Last Change: 54 day(s), 01h:07m:56s ago
LinkTrap: Enabled
Link Autonegotiation: Enabled
Link Speed: 1000Mbps
Link Duplex: Full-Duplex
Flow Control: Disable
Energy Saver: Disabled
Energy Saver Oper Status: No Power Saving
BPDU-guard (BPDU Filtering): Disabled
BPDU-guard (BPDU Filtering) Oper Status: N/A
SLPP-guard: Disabled
SLPP-guard Oper Status: N/A
SLPP: Disabled
SLPP Oper Status: N/A

*****VLAN interfaces configuration*****
Filter Filter
Untagged Unregistered
Port Frames Frames PVID PRI Tagging Name
---- -------- ------------ ---- --- ------------- ----------------
30 No Yes 2527 0 TagAll Port 30

*****VLAN ID port member configuration*****
Port VLAN VLAN Name VLAN VLAN Name VLAN VLAN Name
---- ---- ---------------- ---- ---------------- ---- ----------------
30 1 Default 908 DMZ-TMG 909 NetMGMT
1700 DGenUser 2360 WLThick07-A 2507 PrintersD
2527 DAPControl 3407 VOIPA7
---- ---- ---------------- ---- ---------------- ---- ----------------

*****Spanning-tree port configurations*****
Port Role State STP Status Oper Status
---- ---------- ---------- ---------- -----------
30 Designated Forwarding Enabled Enabled


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