Three times a year, the IMS Forum conducts interoperability test events called plugfests. Last month, its members gathered at the University of New Hampshire interoperability lab in Durham for the second event. The forum and some of its vendors will be presenting the results of their efforts in the IMS Forum booth at NXTcomm. Manuel Vexler, a member of the board at the forum, spoke with Telephony’s Tim McElligott about the event and about the evolving world of IP multimedia subsystem.

On expectations for Plugfest II: Plugfests are serial events, and this is our midpoint for the year. The primary focus of these events is building the infrastructure. Plugfest II starts to focus on applications and services and the way they interoperate with the network layer. We are slowly building a test plan, and by doing that we are building a multivendor, multicarrier network in the lab. We start with voice because it is still a major focus of most service providers today. In more detail, we are testing voice over IP (VoIP) and applications and services for the enterprise. We’re also testing voice continuity and fixed/mobile convergence. Some members want to conduct [short message service] testing. And Plugfest III will definitely be testing video and IPTV.

On the benefits of interoperability testing for IMS: We think a lot of our value comes from the quadruple play. In a homogeneous network [like some of the Tier 1s], you can pretty much deploy whatever you want because you own all four pieces of the puzzle or are building them. Small or medium-sized service providers need partnerships to build these pieces. These multivendor, multi-service provider networks have to deliver the same types of services. It is important at this time to have interoperability, otherwise both the vendors and service providers will be driven crazy. When you have the same application working four different ways, you end up with a huge support staff. Plus, this is not an easy exercise. You work with your competitors and feel like you’re being watched by the whole world.

Many of our smaller vendors are on the cutting edge of interoperability because they believe that if they can prove they are interoperable, they can lead the market in innovation. Plugfests give them the technical ability to test and correct things. And testing one-on-one with other vendors is expensive, so with 15 to 20 vendors in a single lab, they can do that many more times what they could do back in their office.

On what the IMS Forum will be doing at NXTcomm: We plan to have the results of the plugfest by NXTcomm, and we will have three or four partners there discussing their work. So far, we will have Argela Technologies, a Turkish company that specializes in applications and services; Bridgewater, a [home subscriber server] vendor from Canada; and ReefPoint talking about security; plus, a number of sponsors, including Empirix, Ixia and Sonus Networks. ReefPoint is also a sponsor.

On his frustration with IMS label abuse: I joke that the first surge in sales in IMS was the label vendors, so people could put IMS labels on their equipment. I do think the term is more commoditized than it should be, and that has had a negative impact. I hope participants in the industry will get more precise with the term because there is no way other than IMS to get out from the flatness we have today.

There are no other simple standards or activities that will lead to the next-generation network. As a matter of fact, now that we are doing interoperability testing, you can see some interesting behavior in the industry. You see companies that are forward-moving and nimble versus companies saying they don’t want to be part of any lab—who want to control everything, almost to a paranoid level. How can you be interoperable if you are trying to control everything?