Inconsitent inferior PVST BPDU received on VLAN 10

danielrattee · ‎06-12-2023

Good Morning,

Some insight before the question:

I have Ruckus APs creating a bridge between a C2960 and C9300 stack. This works, but I am wanting to replace them with Aironet 1830s so that if there is an issue, I can swap the APs out and restore the bridge.

I have configured the Aironets using mobility express and when I place them on the drops the Ruckus APs were on, they bridge. I am able to ping the AP that is connected to switch 50. Once I place the Aironets I am unable to reach switch 50 though, and I know why based on the error message.

Sw-50#

Jun 11 17:31:12.851: %SPANTREE-2-PVSTSIM_FAIL: Blocking root port Gi1/0/1: Inconsitent inferior PVST BPDU received on VLAN 10, claiming root 4106:XXXX.6a85.XXXX
Jun 11 17:31:12.854: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
Jun 11 17:31:12.858: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan600, changed state to down

XXXXSW-050#show spanning-tree root (with the Aironet connected)

Root Hello Max Fwd
MST Instance Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
MST0 4097 XXXX.6a85.XXXX 20001 2 20 15 Gi1/0/1

XXXXSW-050#show spanning-tree root (with the ruckus connected)

Root Hello Max Fwd
MST Instance Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
MST0 32768 0027.9006.YYYY 0 2 20 15

XXXXSW-050#show spanning-tree

MST0
Spanning tree enabled protocol mstp
Root ID Priority 4097
Address XXXX.6a85.XXXX
Cost 20001
Port 1 (GigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32768 (priority 32768 sys-id-ext 0)
Address 0027.9006.YYYY
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Root BKN*20000 128.1 P2p Bound(PVST) *PVST_Inc
Gi1/0/2 Desg FWD 200000 128.2 P2p Edge
Gi1/0/6 Desg FWD 200000 128.6 P2p Edge
Gi1/0/8 Desg FWD 20000 128.8 P2p Edge
Gi1/0/10 Desg FWD 20000 128.10 P2p Edge
Gi1/0/11 Desg FWD 20000 128.11 P2p Edge
Gi1/0/13 Desg FWD 20000 128.13 P2p Edge
Gi1/0/15 Desg FWD 20000 128.15 P2p Edge
Gi1/0/17 Desg FWD 20000 128.17 P2p Edge
Gi1/0/20 Desg FWD 20000 128.20 P2p Edge
Gi1/0/22 Desg FWD 20000 128.22 P2p Edge
Gi1/0/23 Desg FWD 20000 128.23 P2p Edge

No other configuration changes have been made on SW-50, I am only swapping out AP brands. From some of the things I have read while searching for some answers it indicates that I may have to make changes to priority. I'd like to not make changes that might break the functionality of the Ruckus APs that are currently doing what they are supposed to do, and I am unfamiliar with spanning tree and BPDU.

Is there anything I can do to make the Aironet APs work in the same matter as the Ruckus APs?

MHM Cisco World · ‎06-12-2023

https://www.cisco.com/c/en/us/support/docs/wireless/aironet-1100-series/46141-vlanswireless.html

You need vlan in aironet if you use pvst

MHM Cisco World · ‎06-12-2023

Are you sure confg correct SSID-VLAN mapping ?

danielrattee · ‎06-12-2023

What you linked reads as each VLAN needs its own SSID. I have the Aironets set to bridge and transparent vlan for ethernet bridging, so an SSID shouldn't come into play here, correct?

I know the bridge works because I can ping the AP that is connected to SW-50 from my laptop that has a connection to my core network switch.

MHM Cisco World · ‎06-12-2023

How sender receiver AP know this data for this vlan or that vlan?

Ap use different ssid for each vlan.

Check link i share again

Flavio Miranda · ‎06-12-2023

Hi

XXXXSW-050#show spanning-tree root (with the Aironet connected)

Root Hello Max Fwd
MST Instance Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
MST0 4097 XXXX.6a85.XXXX 20001 2 20 15 Gi1/0/1

XXXXSW-050#show spanning-tree root (with the ruckus connected)

Root Hello Max Fwd
MST Instance Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
MST0 32768 0027.9006.YYYY 0 2 20 15

Put the Aironet on the same Priority as the Rucks 4097

danielrattee · ‎06-12-2023

Thanks for the response,

I have not made any changes (well, except for swapping the AP) on SW-50. Currently has the following:

XXXXSW-050#show spanning-tree detail

MST0 is executing the mstp compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 0, address 0027.9006.a500
Configured hello time 2, max age 20, forward delay 15, transmit hold-count 6
We are the root of the spanning tree
Topology change flag not set, detected flag not set
Number of topology changes 47 last change occurred 19:41:28 ago
from GigabitEthernet1/0/1
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0

Port 1 (GigabitEthernet1/0/1) of MST0 is designated forwarding
Port path cost 20000, Port priority 128, Port Identifier 128.1.
Designated root has priority 32768, address 0027.9006.a500
Designated bridge has priority 32768, address 0027.9006.a500
Designated port id is 128.1, designated path cost 0
Timers: message age 0, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default, Internal
Loop guard is enabled by default on the port
BPDU: sent 35366, received 0

Would putting a different AP on Gi1/0/1 cause the port configuration to change priority?

Flavio Miranda · ‎06-12-2023

No but as per this log:

un 11 17:31:12.851: %SPANTREE-2-PVSTSIM_FAIL: Blocking root port Gi1/0/1: Inconsitent inferior PVST BPDU received on VLAN 10, claiming root 4106:XXXX.6a85.XXXX

It seems the Aironet send BPDU claming to be root. Probably the switch has priority of 32768 and the Aironet may be winning due the mac address

danielrattee · ‎06-12-2023

It seems the Aironet send BPDU claming to be root

How would I be able to change this? I do not see an option for it in Mobility Express. Also, I recently had to rebuild the Ruckus AP configuration to restore the bridge and this issue did not come up.

Is this a configuration change I am making on SW-50, or on the Aironets?

Flavio Miranda · ‎06-12-2023

On the switch 50, set it as root for the vlan you are using

spanning-tree vlan X root primary

danielrattee · ‎06-12-2023

Am I reading this wrong? it is already set as the root:

XXXXSW-050#show spanning-tree root detail
MST0
Root ID Priority 32768
Address 0027.9006.a500
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

The above is with the Ruckus connected....I'm not sure why the Aironet is changing the settings on SW-50

MHM Cisco World · ‎06-12-2023

why because you have two STP, one MST and other PVST, the config work before, so dont play with STP only make Aironet behave same as Rukus

Giuseppe Larosa · ‎06-12-2023

Hello @danielrattee ,

@MHM Cisco World is right the Cisco Aironet are using PVST but your switch is configured in MST mode and the problem is caused by inconsistent interaction between the downstream Cisco switch running MST and the Cisco AP.

As suggested by @Flavio Miranda you need to decrease the switch priority on the downstream switch to a value lower then 4096 for example 0 to make it able to win in every VLAN.

but you have MST so your configuration has to be made for MST giving MST0 a 0 priority.

Hope to help

Giuseppe

danielrattee · ‎06-15-2023

@Giuseppe Larosa wrote:
Hello @danielrattee ,
@MHM Cisco World is right the Cisco Aironet are using PVST but your switch is configured in MST mode and the problem is caused by inconsistent interaction between the downstream Cisco switch running MST and the Cisco AP.
As suggested by @Flavio Miranda you need to decrease the switch priority on the downstream switch to a value lower then 4096 for example 0 to make it able to win in every VLAN.
but you have MST so your configuration has to be made for MST giving MST0 a 0 priority.
Hope to help
Giuseppe

Would setting the MST0 a 0 priority affect the ability for the existing Ruckus APs to function as they are now?

Is there a command that will only change MST0 settings, or would I still need to use the vlan priority command for 1, 10, and 600?

Flavio Miranda · ‎06-12-2023

It is the root with priority 32768. It turns out that the Aironet is onboarding the network with the same priority 32768. If there is a tye, they will look out something else like the mac address for the tye break.

If you add the command "spanning-tree vlan X root primary" there will be not negociation.