December 19, 2006

IMS Update:

Live Learning and Plugfests

By Monta Hernon and Jonathan Tombes

Plenty of questions surround IP multimedia subsystem (IMS). If you're still wondering what it is and how it relates to cable technology, you can't go wrong by joining tomorrow's SCTE Live Learning with Cisco Fellow Jonathan Rosenberg.

As a co-author of the session initiation protocol (SIP), which was incorporated into IMS in its earlier, 3rd Generation Partnership Project days, and author of SIP for presence and IM (SIMPLE) and other key protocols, Rosenberg is certainly someone you'd like to see in front of this classroom. He can answer not only the question of what IMS is, but also where it's going, what's holding it up and what initial steps cable operators are likely to take along an IMS migration path.

As for where the broader, noncable-exclusive "IMS community" is headed, one clue lies in an event scheduled for mid-January (post-CES, pre-ET) that is focused not on architectures but rather services and applications. That event is first in a series done by the IMS Forum, called Plugfests.

IMS interops

Aside from being snappy, the word plugfest connotes interoperability. That's why the IMS Forum adopted the term to describe a series of events it is hosting with the goal of developing an industry-recognized test plan, and hence, interoperability certification, for IMS applications and services. The first of these will occur Jan. 15-19 and encompass all three broadband media.

"We are testing all these IMS services across multiple IMS networks, including wireless, cable and wireline to ensure they are interoperable in real-life conditions," Manuel Vexler, technology strategist for CopperCom and head of IMS interoperability for the IMS Forum, said.

Most of the participants in the event contributed to the test plan. They are under a nondisclosure agreement regarding the plan and its results. "We are not there as a referee of what works and what doesn't. We create an environment for them to troubleshoot and make things work," Vexler explained.

The IMS Forum has structured the events according to four phases: a reference test environment, enhanced interoperability, performance and security. "Of course, you should not look at that we are not testing security until phase four, for example. But we want that kind of focus so we are building up in each phase. We are going deeper and deeper into functionality and service," Vexler said.

Initially the concentration will be on voice features. In generic terms, applications will include VoIP, voice for enterprise applications, IP PBXs, fixed-mobile convergence and presence.

Troubleshooting and testing

The first IMS Plugfest event will be more about troubleshooting and testing interoperability, not necessarily about performance testing. "First we want to make sure the applications do work," he said.

"[Vendors] have to do [these tests] anyway. Usually they are doing this by paring themselves. [They do a] one-to-one test that is expensive and somewhat incomplete. You don't have other people around you testing their equipment at the same time," he added, noting that he expects a dozen participants at the first Plugfest, including Sonus and Tekelec, both of which are suppliers for cable companies.

The test site will be neutral. Plugfest will take place at the UNH Lab in Durham, NH, which is associated with the University of New Hampshire. "The university is well-known. They are testing other products and standards," Vexler said. The plan is to host three Plugfests per year, with the second taking place either at the end of the second quarter or the beginning of the third quarter of 2007.

- Monta Hernon and Jonathan Tombes