Office Communications Server 2007: Microsoft goes VoIP (Part 1)

If you would like to read the next part in this article series please go to Office Communications Server 2007: Microsoft goes VoIP (Part 2)

Microsoft has entered the world of VoIP telephone systems with its Office Communications Server platform. But will Redmond make an impact in this crowded space? Here, the standards and strategic position of this new product are revealed and explored.

Office Communications Server 2007: Microsoft goes VoIP

Microsoft has officially entered the domain of IP telephony, and the industry is both excited and wary. The excitement is due to the potential of an all-MS IP communications solution; alongside Exchange messaging, Active Directory, instant messaging, and the Office Communicator client, a Windows-based IP telephony server certainly has its appeals. The wariness, on the other hand, probably stems from Microsoft’s stalwart reputation for “flavoring” the standards they choose to build their solutions, and perhaps from their relatively late entrance into the VoIP arena.

Not very long ago – meaning 24 months or so – Microsoft was on record as saying they were not interested in producing a Microsoft-branded PBX (private branch exchange) telephone system. In fact, some people at Microsoft told me that Redmond was looking to sell software to run on Avaya, Shoretel, and Cisco chassis, in much the same way Windows Server runs on Cisco’s CallManager PBX server. At that time, the standard response was, “We would love to sell our software to those guys.”

A New PBX Strategy for Microsoft

But, as with all industries Microsoft creeps into, the arrival of a full-blown Microsoft PBX platform was inevitable. The impact of such a product on the telecom equipment business – and on your business – may be significant. So before we peek under the hood of Microsoft’s new unified communications environment, let us take a look at what we know, and what is still a mystery, about Microsoft’s rookie VoIP server product.

Earlier this year, Microsoft introduced the beta version of Office Communications Server 2007 (OCS), which took Live Communications Server 2005 as a starting point and added VoIP support, allowing desktop PCs and IP telephones to place and receive calls. OCS keeps all of its predecessor’s features, which included instant messaging with presence and e-mail. New to OCS is the ability to act as a telephone switch. A telephone switch is a device that connects calls between phones on a network. Typically, these phones all use the same signaling protocol, be it a legacy standard like those used on the public telephone network, or a next-generation VoIP standard.

Indeed, because of Microsoft’s decision to support the VoIP standard known as SIP (session initiation protocol), OCS will support a wide range of handsets, conference stations, and paging equipment. Users of Microsoft’s Office Communicator software will also be able to place and receive SIP-based phone calls. This has sweeping implications for all kinds of telephony applications – imagine a customer support helpdesk with voice, video, and desktop sharing all integrated into a singularly managed server application, or a laptop user who is able to take his software-based phone with him anywhere on the network. Sure, none of this stuff is really new – it’s just new to Microsoft.

SIP also empowers OCS to communicate with other VoIP-enabled PBX systems, allowing calls to be switched between phone users on an OCS server and those on, say, an Avaya Media Server. This is an important consideration for administrators who are considering adding OCS to an existing IP telephony network, or for those considering a wholesale switch to the Microsoft-based telephony solution.

Office Communications Server offers mobility to SIP users, too. While it’s always been difficult to support mobile users on a SIP-based PBX, due to problems with NAT firewalls that are so commonly encountered on the road, Microsoft has wisely adopted the ICE family of standards for mobility and firewall traversal, which it helped to create.

What remains to be seen, however, is just how well an all-OCS phone system performs in an intensive enterprise environment – and there are some hard limitations. For example, OCS’s video-conferencing features work only with on-premise users, though Microsoft offers OCS users the ability to do off-premise conferences using the hosted LiveMeeting service. Beyond web conferencing, there have been very few field reports about the SIP capabilities of OCS. SIP is a very capable protocol, allowing set up of video calls, text messaging, and other forms of streaming media, though OCS is limited in its support of SIP’s vast array of media setup capabilities. This is nothing unique though – most IP telephony vendors who support SIP only support a subset of what can be done with the protocol. It’s not uncommon for a SIP-based PBX to support just telephone calls and not text messaging or video.

Then there is the issue of scalability. Microsoft’s documentation for OCS indicates that it will function in a multi-server configuration, for reasons of fault-tolerance and scale. Of course, even with this in mind, Microsoft isn’t advising anybody to dump a current phone system and switch whole-heartedly to Office Communications Server. Beta is beta, after all. Plus, it’s still not fully understood if Redmond is positioning OCS against the likes of well-entrenched players like Nortel, Siemens, and Cisco, or if the desire is to cooperate on telco turf. Ghostly echoes of Novell NetWare abound.

And that’s the real issue: It’s not exactly clear what Microsoft’s strategic goals for OCS actually are. Is there any intention of making OCS the mature, Avaya-slaying warrior that Microsoft geeks have been dreaming of? Or is OCS just another side product that ends up a free add-in feature (like Sharepoint) or something that gathers dust in the janitor’s closet at MS headquarters, never really gaining widespread acceptance or innovating (like ISA Server)?

Open Standards, Closed Platform

Standards purists continue to question Microsoft’s approach to SIP, despite overwhelming consensus that SIP was the right choice for OCS. Office Communicator, Microsoft’s SIP client software for Microsoft Office, only works with OCS – that is, you can’t mate it with another SIP server. So if you need Office Communicator (instant messaging, voice calls, video calls), then you’re basically stuck using OCS. Perhaps at some point, Communicator will get along with other SIP servers, just as Office Outlook supports e-mail servers other than Exchange.

The stated reason for this limitation is Active Directory. Microsoft wants to deliver a fully-integrated enterprise telephony experience, and this means leveraging the ubiquitous directory service in OCS and Office Communicator. Just about everybody with a Windows networking environment uses Active Directory for authentication and centralized resource management, so the implications for a phone system are obvious. When combined with Exchange 2007’s new voicemail features, “click-to-call” and “click-to-voicemail” shortcuts within Outlook, the vision of an all-Microsoft telecom network really begins to take shape.

In the Pipeline

Just because Active Directory is central to OCS’s functionality doesn’t mean that non-PC devices like IP phones will be excluded from the party. Indeed, Polycom has already shown a WiFi IP phone that runs an embedded version of the Office Communicator software – and the user interface on this phone is nearly identical to that of the PC version. Microsoft has also demonstrated unbranded hardphones that contain a Communicator-like interface – with indications for waiting messages, contact lists, and the other goodies that are a part of the desktop Communicator software.

Microsoft is rumored to be working on a proprietary new sound codec, too, aiming to optimize the quality of calls even in a low-bandwidth environment. The name or characteristics of this codec haven’t leaked out yet, but it appears Redmond chose not to license a codec from market-leading Global IP sound, which produces the adaptive (variable bit-rate) codec currently used by Skype and other major VoIP players. What’s more, Microsoft’s codec is software-based, meaning it doesn’t require DSP hardware and can be implemented anywhere Windows runs – mobile devices, next-generation low-cost IP phones, and certainly a future version of Office Communicator.

In the next installment of this column, I’m going to rip the lid off of Office Communications Server and Office Communicator, pit them against open source alternatives, and get these old hands dirty discovering if OCS is really ready for prime time. I invite you to do the same. You can download the Office Communications Server 2007 Beta at

If you would like to read the next part in this article series please go to Office Communications Server 2007: Microsoft goes VoIP (Part 2)

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