I pressed Pounds on the L2 extensions he mentions, but I have yet to receive an answer. I don't see any extensions or language in either the draft RFC or in the other documents within the working group that indicates an alternative link state protocol like FSPF can be used with TRILL and remain standards based. I may have missed something, but I don't think so.
Cisco's FabricPath, which uses IS-IS for the link state protocol, also plays games with the standard because it adds some secret sauce to make FabricPath better. Cisco was open about the fact that FabricPath was using a pre-standard implementation of TRILL with proprietary features.
Pounds goes on to say "Once interoperable TRILL solutions are available, network architects are going to have to weigh the value of a multi-vendor TRILL network versus a single-vendor fabric. A lot of value that we bring in VCS is above and beyond what the standard provides. Cisco will claim the same with FabricPath,." He is spot on. Cisco said as much in their FabricPath announcement.
If you want to run a multi-vendor switch environment, you will face a problem with both Brocade and Cisco's positioning of TRILL. You, the IT buyer, will have to choose either the new and improved TRILL, or the standards compliant TRILL which is not new and improved and therefore is not as good. That is what Brocade and Cisco will tell you and it is how they lock you in. There doesn't seem to be any interest by either vendor in supporting both standard TRILL and their proprietary versions simultaneously. I don't know why Brocade or Cisco can't implement a dual stack supporting standard TRILL and their flavor of TRILL simultaneously. It's not like running multiple routing protocols, or in this case, link state protocols, is new and uncharted territory. Fact is, neither wants to.
If you are using Brocade's VCS or Cisco's FabricPath just for FCoE, it doesn't really matter what they do to ensure the FC frames make it across the fabric in the proper order, because the encapsulated FC network is a closed environment. But if you want to use loss-less Ethernet and layer 2 multi-pathing for anything else, like the rest of your network equipment, standards-compliant protocols are a must. There are already two standards-based layer 2 multi-path protocols, TRILL and SPB, which are not interoperable. Now with vendor tweaks, there are going to be more versions of protocols than there are vendors. Thanks for thinking of the customer.
