Blog: Cisco Adds SIP to Call Manager, Finally

Next month, Cisco will introduce the next release of Call Manager, version 5.0, at the VoiceCon show in Orlando. Lots of changes are to be expected, including support for Linux in addition to Windows Server, and finally support for SIP clients.

That last fact is a big deal. Unless you've been comatose for the past few years or otherwise blissfully ignorant of the VoIP industry, you know Call Manager is the only major IP PBX to not offer SIP client support. Cisco has offered SIP trunking and offers a SIP server for the carrier market, but has no such offering for the enterprise.

The official reason, according to Cisco, is that SIP isn't mature enough for the enterprise. But the scuttlebutt says that 18 months ago internal politics at Cisco killed the SIP efforts to produce an enterprise-class SIP server. Fingers pointed to Marthin DeBeer, then Cisco’s vice president and general manager, and Richard Platt, then Cisco’s vice president of engineering, for eliminating Dreadnaught, a prototype enterprise SIP server. The two were responsible for Call Manager's development and supposedly were threatened by the Dreadnaught team’s ability to add 80 percent of Call Manager's ability within six months, or so the rumors go.

Adding features to CCM has been cumbersome. It took two years to add Music on Hold, for example. Even today, CCM uses its own Skinny Client Control Protocol (SCCP), which lacks presence and isn't well suited for a distributed architecture.Cisco's SIP adoption may well address at least some of those problems. With SIP support, clients will be able to carry rich presence, reflecting various states and not just whether they’re online. Mobility will also be enhanced as next generation mobile services use IMS, which is based on SIP

What's more, SIP will help IT reduce upfront telephony costs because companies can purchase low-cost SIP phones—at least that's the theory. Enterprise IT will want to look carefully at whether it’ll receive the same level of telephony functionality from a third-party phone that it would receive from Cisco phone.

IT also must look at how much money can be saved by choosing a third-party telephone. The different interfaces and functions on the phones may save a few dollars upfront, but could well carry higher operational costs over the long run.

Posted by David Greenfield February 17, 2006 05:35 AM