Chapter 3: Microsoft OCS 2007 and 2007 R2
overview
Microsoft Office Communications Server 2007 R2 offers instant messaging (IM), presence, Web
conferencing, audio/video (A/V) conferencing, and telephony solutions that can support enterprise-level
collaboration requirements. Office Communications Server 2007 R2 builds on the IM, enhanced presence,
on-premises conferencing, and Enterprise Voice features that are provided by Office Communications
Server 2007, providing chat room as well as additional IM, conferencing, and telephony functionality, such
as interactive voice response (IVR) and conferencing auto-attendant.
To facilitate calls to and from the PSTN, OCS 2007 and 2007 R2 server requires two external components:
• Basic Media Gateway—devices that translate signaling and media between the PSTN and the OCS
network
• Mediation Server—provides signaling and media translation between the OCS Server and a basic
media gateway
The main functions of the Mediation Server are as follows:
• encrypting and decrypting SRTP (Secure Real-time Transport Protocol) on the Office
Communications Server side
• translating SIP over TCP to SIP over mutual TLS
• translating media streams between Office Communications Server and the media gateway
A basic hybrid media gateway collocates a basic media gateway with a Mediation Server on a single
device. Microsoft Mediation Server software is included along with Microsoft OCS 2007 and 2007 R2
server software package. Mediation Server (OCS 2007) requires server hardware based on 32 bit CPU
and Windows 2003 operating system and Mediation Server (OCS 2007 R2) requires server hardware
based on 64 bit CPU and Windows 2008 operating system.
The Avaya AG2330, Avaya SR2330, and Avaya SR4134 can all serve as basic media gateways for
Microsoft OCS 2007 and 2007 R2. In addition, the SR4134 can also work as basic hybrid media gateway
when installed with a medium server module. This server module comes in 2 flavours - 32 bit CPU version
with Windows 2003 OS pre-installed, and 64 bit CPU version with Windows 2008 OS pre-installed.
Mediation Server modules are not supported on the AG2330 and the SR2330. The AG2330 and SR2330
require an external Mediation Server device to work with Microsoft OCS 2007 and 2007 R2 Server.
Avaya AG2330/SR2330/SR4134 Quick Start Guide
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