One of the following operating system is required for Mediation Server:

• The 64-bit edition of Windows Server 2008 Standard, or the 64-bit edition of Windows Server 2008 Enterprise
  
  
• Windows Server 2003 R2 Standard x64 Edition with SP2, or Windows Server 2003 R2 Enterprise x64 Edition with SP2
  
  
• Windows Server 2003 Standard x64 Edition with SP2, or Windows Server 2003 Enterprise x64 Edition with SP2
  
  

The following table outlines the recommended hardware requirements for a Mediation Server.

Table 1. Mediation Server

The minimum hardware configuration (for up to 125 concurrent calls or 5 T1) is as follows:

• Single Processor Dual Core running at 3GHz
  
  
• 2GB RAM
  
  
• 30GB hard disk
  
  

To help ensure the physical as well as logical separation of your Enterprise Voice infrastructure from the media gateways, install Mediation Server on a computer that is equipped with two network interface cards (NICs). One card faces the gateway, and the second card faces the Office Communications Server 2007 R2 server that acts as the Mediation Servers internal next hop.

When you install Mediation Server, the Deployment Wizard detects the presence of the two network cards and writes their IP addresses to the Office Communications Server listening IP address list and the Gateway listening IP address list, both on the Generaltab of the Mediation Server Propertiesdialog box.

The Office Communications Server listening IP address is the address on an advanced media gateway that listens for call traffic from Office Communications Server. Until advanced media gateways are available, this address corresponds to the network card that serves as the internal edge of the Mediation Server.

Important:

The IP address that you select from the Office Communications Server listening IP address must match the address that is returned by a Domain Name System (DNS) query on the fully qualified domain name (FQDN) of the Mediation Server. If the two addresses do not match the IP address listed in DNS for your FQDN, you cannot connect and call traffic will be directed to an interface that is not listening for Office Communications Server traffic instead of to the one that is listening.

The Gateway listening IP address is the address on the Mediation Server that listens to traffic from a basic media gateway or basic hybrid media gateway. For Office Communications Server 2007 R2, this address corresponds to the network card that serves as the external edge of the Mediation Server.

Note:
It is possible to configure both edges on a single adapter card, but it is not recommended.

For basic media gateways, the bandwidth requirement between gateway and Mediation Server is 64 kilobits per second (Kbps) for each concurrent call. Multiplying this number by the number of ports for each gateway is a fair estimate of the required bandwidth on the gateway side of the Mediation Server. On the Office Communications Server side, the bandwidth requirement is considerably lower.

When configuring Mediation Server, you are advised to accept the default media port gateway range of 60,000 to 64,000. Reducing the port range greatly reduces server capacity and should be undertaken only for specific reasons by an administrator who is knowledgeable about media port requirements and scenarios. For this reason, we recommend that you do not alter the default port range.

High-bandwidth traffic such as voice and video tends to stress poorly provisioned networks. Limiting media traffic to a known range of ports makes it easier to troubleshoot these types of problems.