MSTP with RSTP

[Muhammad Kamran Shahzad]

Dear Experts
Advise solution for below
We have mixed topology with Huawei and Cisco switches
Currently we are running RSTP and unfortunately it's not compatible between both switches and we have engages huawei support and they verified that RSTP between huawei and cisco isn't compatible so run MSTP
Is this possible to configure Root Bridge (Huawei) on MST and rest all switches running Rapid_pvst and will they elect Huawei as root bridge ?
We set Huawei as MST root bridge but unfortunately Cisco switches still not accepting huawei as RB

Also previously we have tried to move ring topology in MST and after moving we lost connectivity to all switches and when we reach on site and connected console we see ports were blocked with Pvst_Inc issue ?
Why PVST_inc was there as total ring was on MST but client side switches were still running r_pvst
Please advise how we can achieve this ?
We want Huawei work as Root bridge but currently cisco only accept huawei as RB on vlan1 
 

[M02@rt37]

Hello @Muhammad Kamran Shahzad 

To achieve such configuration with Huawei as the root bridge, it is recommended to configure MSTP on all switches and set the bridge priority accordingly. Additionally, ensure that all switches are consistently configured in either MSTP or Rapid-PVST mode to prevent any issues with connectivity.

Ensure on Cisco side that the bridge priority is higher than that of the Huawei switch to prevent the Cisco switch from becoming the root bridge.

After configuring the switches, the root bridge should be elected based on the bridge priority configured on each switch. If the Huawei switch has the lowest bridge priority, it should become the root bridge for all VLANs.

Regarding the issue you faced when moving the ring topology to MSTP, it is possible that the PVST_Inc issue occurred due to a misconfiguration or inconsistency between the MSTP and Rapid-PVST modes. It is recommended to carefully review the configuration and ensure that all switches are running in the same mode (either MSTP or Rapid-PVST) and that the root bridge is properly configured.

[Muhammad Kamran Shahzad]

Hi Dear
Thanks for your reply
I have configured Huawei as root and priority for vlans is 0 because switch is Root Primary in MSTP mode
I have configured only 1 instance and mapped all vlans to it in Huawei
However Cisco switch is set to Rapid_Pvst mode but cisco only selecting huawei as Rood bridge in vlan1
Below is the STP configuration of Huawei in MSTP

display stp region-configuration
Oper configuration
Format selector :0
Region name :DreamNet
Revision level :0

Instance VLANs Mapped
0 1 to 4094


And see below output in Cisco for Vlan1 which is selecting Huawei as Root Bridge 

Spanning tree enabled protocol rstp
Root ID Priority 0
Address 00e4.06a0.6be0
Cost 3
Port 49 (TenGigabitEthernet1/49)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 4097 (priority 4096 sys-id-ext 1)
Address 6400.f1cd.9c40
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/43 Desg FWD 4 128.43 P2p Peer(STP)
Gi1/45 Desg FWD 4 128.45 P2p Peer(STP)
Te1/49 Root FWD 2 16.49 P2p


Show below output of STP info in cisco switch other than vlan 1

Spanning tree enabled protocol rstp
Root ID Priority 61861
Address 6400.f1cc.e740
Cost 4
Port 49 (TenGigabitEthernet1/49)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 61861 (priority 61440 sys-id-ext 421)
Address 6400.f1cd.9c40
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/2 Desg FWD 19 128.2 P2p
Gi1/3 Desg FWD 19 128.3 P2p
Gi1/43 Desg FWD 4 128.43 P2p
Gi1/45 Desg FWD 4 128.45 P2p
Te1/49 Root FWD 2 16.49 P2p

as per above output, vlan 1 priority is 0 which is from Huawei but Vlan421 priority is 61440 + System extend ID

Please advise

[balaji.bandi]

Some suggestion between HW and Cisco switch inter-operability :

https://forum.huawei.com/enterprise/en/interoperation-and-replacement-guide-for-spanning-tree-protocols-on-huawei-and-cisco-switches/thread/506149-861

You can have any switch root bridge and the cisco switch can participate in the STP (make sure the cisco switch high the priority than HW switch, by default cisco priority is 32768/9 until you set manually something lower)

the post-show output of STP on both sides why it's not working to understand your config and show output?

[Muhammad Kamran Shahzad]

Thanks @balaji.bandi  for Response
We have 10 Cisco Aggregation switches down to Huawei Root Bridge and 13 Huawei swithces
We have many Access Layer as well, Please advise how safely we can move devices to MSTP specially Cisco as Cisco blocking uplink port with PVST_Inc issue
Is this because of access layer switches ?
If yes then is this possible to apply bpdufilter on the port where Access switch are connected ?

[balaji.bandi]

STP BLOCKING and STP Priority 2 different areas and but some time can together to solve some issues. (if the network is like a RING)

STP Priority set the VLAN where to be the root bridge

STP BLOCKING is Due to loops in the network.

To understand your problem you need to provide a high-level diagram of how these are connected. and what config each switch has ?

Do you have any Loops in the network, so you can avoid balancing the VLAN to use different paths.

[Muhammad Kamran Shahzad]

Hi @balaji.bandi 
Sure, Let me create a network diagram and will share it soon
Further more there is no loop in network and currently whole network is in production and in RSTP mode (Huawei) and Rapid_Pvst cisco and in case of any fiber break , traffic auto shift to other link as well but we have a root bridge election problem

As soon as we move to MSTP then we have PVST_Inc issue on uplink port 
Better to discuss in details after network topology analysis
Let me share

[Muhammad Kamran Shahzad]

Attaching Network Diagram

[MHM Cisco World]

@Muhammad Kamran Shahzad @balaji.bandi 
you mention BPDUfilter and it LAST option we have here 
I DONT RECOMMEND IT AT ALL 
but for your info. 
for me any STP can divide into ISLAND between these ISLAND there is bridge, this bridge always face STP incompatibility,
you can disable the STP (BPDUfilter) if and only if there is ONE way (one bridge) between two ISLAND, 
here your network appear complex but it different ISALND connect to one big HUAWE SW ISLAND.
all ISLAND except one is  connect via one link 
I mention how you can solve this also 
you can disable STP and your network will stable. (AGAIN THIS IS NOT RECOMMEND)

[Muhammad Kamran Shahzad]

I have configured MSTP in root bridge and 1 cisco switch in same configuration but cisco block uplink port with PVST_Inc issue
do cisco check whole topology ? if any other switch in topology running pvst or pvst+ then is this normal that this uplink port will be blocked ?
I am just testing before implementation
What will be the best practice to safely move whole topology to mstp without losing access ?
we have 10 Cisco Switches (Aggregation) in ring topology and 13 Huawei Aggregation switches 
How I can safely move above 23 switches in MST mode to avoid PVST_inc on uplink port ?

Thank 

[MHM Cisco World]

I will run lab and check some point'

But before that are pvst error you receive in native vlan of trunk??

[Muhammad Kamran Shahzad]

Hi

yes pvst_inc on uplink which is trunk carrying all vlans

and there is no traffic so I believe all vlans blocked

[MHM Cisco World]

friend 
this is not easy task 
BUT I together will work hard to make it work 
MST send BPDU for each instances 
PVST send BPDU for each VLAN 
cisco have PVST simulation which make port connect MST to PVST simulation the PVST by send BPDU for each VLAN 
this feature need some criteria it explain in below link  
PVST Simulation on MST Switches - Cisco

read it carefully and I will with you until final result 
thanks 
MHM

[Muhammad Kamran Shahzad]

Hi @MHM Cisco World 
Let me create diagram and share with you
and thank you so much for support

[Muhammad Kamran Shahzad]

@balaji.bandi @MHM Cisco World 
Network Diagram Attached
Please check and advise

Thank You