topic Re: Interconnecting 2 Existing Fabrics in ExtremeSwitching (VSP/Fabric Engine)

Interconnecting 2 Existing Fabrics

gtkins121 — Tue, 24 Jun 2025 18:53:49 GMT

Hey,

Fairly new to Extreme & Fabric engine.

I have inherited a fabric engine deployment, 7520's as the Core of the network (still getting used to fabric esq terminology) with a mixture of 4000/5000 switches for the edge. We have an integration with Control in Site Engine for policy enforcement. We have users that roam to our network from a 3rd party (neighboring company) and work within the physical boundaries of our network and there is a longer term strategy to integrate Our fabric with the third parties Extreme fabric. We essentially have areas of our buildings where both companies have representatives collaborating on projects. We want to basically be able to accomodate their segmented VLANs/I-SID's as well as them accomodate ours. Any tips/pointers in the right direction for planning this would be great. I understand at this point that their I-SID's would need to be unique to ours and the VLANs if present on same switch. We are also conscious we want to ensure control, protection and segregate routing information etc. or would it literally just be easier to just have a trunk port between the two fabrics?

Any reference material would be great, or if anyone has experience doing this?

Cheers

Re: Interconnecting 2 Existing Fabrics

EF — Wed, 25 Jun 2025 12:26:19 GMT

Hi gtkins121,

I dont have experience on yuor enviroment so I cant give you tips, but about this "or would it literally just be easier to just have a trunk port between the two fabrics?" I can tell you this works but be carefully with multicast, if you need extend it between independet fabrics is not easy (https://community.extremenetworks.com/t5/extremeswitching-vsp-fabric/spbm-multicast-between-two-fabric/m-p/119025#M2991)

Good luck!!!

Re: Interconnecting 2 Existing Fabrics

Brent_Addis — Wed, 25 Jun 2025 21:39:34 GMT

Honestly this is probably out of scope for a forum. It can be done, but you'll need someone with some fabric experience so I would be looking for a local partner.

Start by auditing i-sids in use. Make sure there is no overlap. Maybe for sanity moving forwards allocate a large segment each so you both "Stay in your lane"

A few thoughts:

I-SIDs must be globally unique across both environments
VLAN IDs (if locally significant) must not conflict when on the same switch
Decide between:
- Full fabric extension (preferred)
- Border interconnect via routed VRFs
- Traditional VLAN trunking (easiest short term, least scalable)

If I was doing this, my next steps would be:

-Document current VLAN/I-SID/VRF allocations

-Align with third party on shared I-SID/VLAN/VRF strategy

-Identify collaboration zones and shared edge ports

-Build test interconnect (start with VLAN trunk or test I-SID)

-Think about your long term model and what kind of shared integration you need

Personally, I believe Fabric is the way to go here and not trunking which is like a 10 year step back, but if you're new to it which you seem to be, search out a local partner for advice.

Re: Interconnecting 2 Existing Fabrics

Roger_Lapuh — Wed, 25 Jun 2025 21:43:18 GMT

gtkins121

this sounds like a perfect request for a multi-area design. Multi-Area will give you the option to decide which ISIDs can talk across the area boundary and you can also control which VRFs and which IP routes you want to redistribute between the entities.

Roger

Re: Interconnecting 2 Existing Fabrics

gtkins121 — Thu, 26 Jun 2025 19:22:23 GMT

Thank you! Multi-Area SPBM right? sounds like the option i need.

Re: Interconnecting 2 Existing Fabrics

gtkins121 — Thu, 26 Jun 2025 19:26:09 GMT

Appreciate the assistance and guidance.