At least that is the verdict of this SearchVoIP article by Michael Morisy. I do agree that the recent R2 release of Microsoft Office Communications Server is not perfect. Some of the issues pointed out by those interviewed in the article are related to scalability- they claim that OCS 2007 R2 is not built to support 10,000 plus users and is limited to small deployments.
However, this article describes how OCS 2007 R2 can be used to support an environment of 100,000 endpoints, and states that one OCS 2007 R2 Enterprise Edition Front End server is capable of supporting approximately 12,500 endpoints by itself.
At the end of the article Mike Stacy, Evangelyze Communications Director of Services, is quoted as saying “R2 is viewed as complementary to the PBX. With R3, I don’t think it’s a secret that Microsoft wants to replace the PBX.”
OCS 2007 R2 may not yet be a PBX-killer, but I think it at least mortally wounded it. OCS 2007 R2 includes the ability to do direct SIP-trunking, connecting the VoIP service directly to OCS without a PBX. One handicap is that Microsoft only supports direct SIP-trunking with two providers at this time. Stacy’s Evangelyze Communications though is set to introduce a product (SmartSIP) that bridges that gap and allows OCS 2007 R2 to be used directly with any VoIP provider- effectively eliminating the PBX and enabling companies to move forward with OCS 2007 R2 while leveraging their existing desktop phone hardware investment.