topic Re: PVST through SPB in ExtremeSwitching (VSP/Fabric Engine)

PVST through SPB

kbetsis — Mon, 05 Aug 2024 12:10:13 GMT

Hi all,

What is the recommended way for tackling PVST+ BPDU flooding through a SPB network?

There is a use-case where three (3) switches are connected to two (2) BEBs and PVST+ BPDUs need to:

1. be allowed on the UNI ports

2. be allowed to be flooded through the BEB NNI interconnection of

PVST+ is needed to offer uplink redundancy to the CISCO switches and have loop avoidance.

The fabric facing design is the following:

CISCO SWITCH1 --> BEB-SW01 UNI PORT 1
CISCO SWITCH2 --> BEB-SW01 UNI PORT 2

CISCO SWITCH3 --> BEB-SW02 UNI PORT 1

BEB-SW1 NNI PORT X <--> BEB-SW2 NNI PORT X

Each UNI port will have multiple VLANS each mapped to their own ISID.

There are multiple other BEB/BCB switches which currently work for the VLAN-ISID mappings as expected and are pure fabric based.

Any recommendation is more than welcomed.

Thank you

Best Regards

Konstantinos Betsis

Re: PVST through SPB

Shaja — Tue, 13 Aug 2024 13:56:11 GMT

I do not think the "fabric care" about it.

Use transparent UNI & those cisco switches will "think" that they are directly connected.

Re: PVST through SPB

kbetsis — Tue, 10 Sep 2024 14:30:09 GMT

Hi Shaja,

What do you mean transparent UNI?

The issue is that BPDU frames are dropped on the SPB backbone and this produces loops.

So the issue is that BPDU frames need to traverse the SPB in order to close the loop and at the same time have the mapping to ISID to offer layer 2 services on the same VLANs.

Re: PVST through SPB

WillyHe — Wed, 11 Sep 2024 13:02:31 GMT

When there is NO communication required for systems connected to the SPB backbone and the Cisco network, then transparent UNI is the solution.

When communication between the SPB backbone and the Cisco network is required then transparent UNI cannot be used.

Re: PVST through SPB

Phil_ — Wed, 25 Sep 2024 12:29:29 GMT

Hi,

if I understand you correctly you need the connection to the SPB backbone to access services there from the cisco switches? If this is correct than you have to use the SPB-STP Multihoming Feature, see this article for further Information: https://extreme-networks.my.site.com/ExtrArticleDetail?an=000082836&q=STP%20multihoming

Unfortunately PVST+ is a proprietary protocol from cisco which is not mentioned by the IEEE foundation and is also not supported by VOSS/Fabric Engine. So if you want to connect the cisco switches to the Fabric Connect Switches, you have to change the Spanning-Tree mode to multiple spanning-tree on the cisco devices and configure SPB-STP Multihoming on the two BEBs on which the cisco devices will be connected or shut the link that is causing the loops by hand or slpp-guard.

I can´t see any other resolution.

Best regards,

Phil

Re: PVST through SPB

Shaja — Thu, 26 Sep 2024 14:03:54 GMT

Cool I did know that you can map MSTP to SPBM.

ieee standard like MSTP or well work RFC like BGP & OSFP

Is better when you run on mulitivendor hardware.