Microsoft: It's all about software

Tightly coupled software stack replaces the PBX in Microsoft's vision of unified communications

Similar to its famous "developers, developers, developers" rant, Microsoft is chanting "software, software, software" as it lays the cornerstones of its unified communications platform.

Microsoft's is an all-software strategy that weaves voice, e-mail, instant messaging, presence, and video conferencing into a suite of communication tools anchored by Office Communications Server (OCS) 2007.


Read Cisco's approach to unified communications.

Watch a head-to-head comparison of Cisco vs. Microsoft UC solutions.


The most dramatic difference between Microsoft's vision and that of the hardware-based unified communications players comes at the junction of the voice and data networks, where Microsoft believes the PBX will die and be resurrected as software. In other words, OCS 2007 becomes you new PBX.

Microsoft's Chief Software Architect Bill Gates in October was blunt in his PBX prognosis. "Once you get software in the mix the capabilities go way beyond what anybody thinks of today when they think of phone calls. This is a complete transformation of the business of the PBX," said Gates at the launch of the company's unified communications platform.

Gates likened the PBX to the mainframe of years ago, an all-inclusive system that lacked flexibility. Gates said moving voice to software would bring efficiencies to workers and IT, and reduce infrastructure and operating costs. (See story on Gibson Gibson Guitars use of Microsoft unified communications products.)

This approach also allows Microsoft to more easily integrate directory services, desktop applications and system management tools.

Click to communicate

The company believes that its voice-enabled unified communications platform will give more than 100 million corporate workers the ability to "click to communicate" by the end of 2010.

Diagram of Microsoft's unified communications vision

Gates says megatrends, such as hardware improvements, abundant bandwidth and a digitized economy have "laid the foundation for voice integration via software and unified communications."

Microsoft believes that as the phone call is revolutionized, the change will bring along screen sharing, video, collaboration and the ability to put rich unified communications capabilities into business applications.

In the Microsoft nirvana, all that will remain at the network's edge is a gateway to translate signaling and media between the Public Switched Telephone Network and the Session Initiation Protocol (SIP)-based OCS 2007.

Certainly such a dramatic switch comes with pros and cons.

On the plus side, OCS can do call switching and routing, and the breadth of the unified communications software is all tightly integrated providing near plug-and-play between OCS and its Communicator client, presence, Exchange messaging, Office applications, data repositories and IP-based desktop and USB handsets built by Microsoft partners.

"What they are trying to do is make it easy for IT people to implement and deploy and they have made a platform that is really compelling for end-users," says E. Brent Kelly, an analyst with Wainhouse Research. "If you already have Outlook and Office, the integration is automatic."

Communicator uses Interactive Connectivity Establishment (ICE) standards which give external users the ability to use VoIP to call into the network, bypassing problems with NAT and firewall transversal that plague SIP-based PBXs.

Microsoft also has won praise for its Real-Time (RT) Audio Codec that improves sound quality, including in low-bandwidth situations.

In addition, the core of the unified communications platform will eventually come under Microsoft's System Center centralized management platform, which provides monitoring, software deployment and eventually automated load balancing and capacity management.

Not so fast

On the down side, Microsoft always has to answer reliability and security questions and it will be no different here. Viruses, worms or denial-of-service attacks could cripple phone and other communications.

"The typical way people deploy VoIP is they put phones on a virtual LAN separate from their data applications so if there is an attack on the data side the phones are not affected, but when you go to a fully software-based architecture it becomes next to impossible to do that isolation," says Irwin Lazar, an analyst with Nemertes Research.

Despite its all-software bravado, today OCS must be coupled with a PBX in many scenarios. The protocol stack in non–Microsoft SIP PBXs must be modified in order to integrate OCS's SIP extensions and the server does not support SIP trunking with a service provider.

Users will have to deploy OCS's Mediation Server to translate proprietary audio formats in standard formats, such as G.711. Larger deployments will need multiple Mediation Servers to handle large call volume.

Not surprisingly, the platform is Microsoft-centric, such as Communicator clients that won't work without modification on non-Microsoft SIP-based servers.

Users will have many components to upgrade, install and tweak including schema changes in Active Directory, creation and installation of certificates and certificate servers, deployment of edge servers for features such as connection to public IM networks, and rollout of a Quality of Experience Monitoring Server to watch voice and video quality.

Partnering up

Microsoft isn't walking into all of this solo. The company has a number of partners including Intel, Texas Instruments, AudioCodes, Dialogic, LG-Nortel, and Polycom, who are all licensing Microsoft's RT codec.

AudioCodes, Cisco, Dialogic, NEC, Network Equipment Technologies, and Quintum are all offering pre-tested SIP gateways. Nortel is offering a SIP Gateway and an IP-PBX that can be paired with Office Communicator.

LG-Nortel (IP phones, Bluetooth headsets), Polycom (IP and USB phones, speakerphone), GN Netcom (USB headsets), Plantronics (USB headsets) and Samsung (LCD Monitor with microphone/speakers) are providing voice end-points for the platform.

Learn more about this topic

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Microsoft Subnet: The independent voice of Microsoft customers

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