Enabling QoS Marking

Communications Server 2007

Microsoft Office Communications Server 2007 and Microsoft Office Communications Server 2007 R2 will reach end of support on January 9, 2018. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.

In order to enable QoS marking in your Office Communications Server environment, you will need to do the following:

  • Enable the Windows QoS Packet Scheduler service on servers and clients.

  • Configure the registry key to enable QoS marking of IP packets sent to and from Office Communications Server.

  • Use Group Policy to set Differentiated Services Code Point (DSCP) values that mark the IP packets if you need values other than the defaults for Guaranteed service type packets (used for audio) and Controlled load service type (used for video).

The Packet Scheduler service is enabled by default on Windows Vista and Windows XP computers. It is, however, not enabled by default on Windows Server 2003 computers. QoS marking is not enabled by default in Office Communications Server because Office Communications Server runs on Windows Server 2003 and QoS marking is dependent on the Packet Scheduler service running on both server and client computers.

  1. Click Start, click Control Panel, and then double-click Network Connections.

  2. Right-click the network connection on which you want to enable QoS marking, and then click Properties.

  3. Under This connection uses the following items, select the QoS Packet Scheduler check box.

  4. When you are finished, click OK.

To enable packet marking by the Real Time Media Communications stack to guarantee that IP datagrams for audio and video will arrive within the guaranteed delivery time, set the value of the following registry key to (DWORD) 1 on both server and client computers in your environment:

HKEY_LOCAL_MACHINE\Software\Microsoft\RTC\Transport\QoSEnabled

CautionCaution:
Incorrectly editing the registry may severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

This marking will set the value of the Type of Service (TOS) Precedence field in the header of the IP packets conveying digital speech to 101 (in binary) and the value of the TOS Precedence field in the header of the IP packets conveying digital video to 011 (in binary). If you want to use different values in the first six bits of the TOS field of the IP packet headers, you can configure your own Differentiated Services Code Point (DSCP) values.

noteNote:
The media stack QoS marking is performed on UDP traffic only because TCP traffic has its own flow control.

  1. Click Start, click Run, and then type gpedit.msc.

  2. In the Group Policy snap-in, expand Computer Configuration, expand Administrative Templates, expand Network, expand QoS Packet Scheduler, and then click DSCP value of conforming packets.

  3. To edit the DSCP value of audio packets, double-click Guaranteed service type.

  4. In the Guaranteed service type Properties dialog, click Enabled.

  5. Click DSCP value, type the value that you want to use, and then click OK.

  6. To edit the DSCP value of video packets, double-click Controlled load service type.

  7. In the Controlled load service type Properties dialog, click Enabled.

  8. Click DSCP value, type the value that you want to use, and then click OK.

Because QoS policies are often tied to UDP or TCP ports, Office Communicator Server 2007 also includes a registry setting to specify the port range for the UDP and TCP ports used in delivering media streams. For media servers (for example, A/V Conferencing Servers, Mediation Servers, A/V Edge Servers) refer to the documentation specific to each product to set the appropriate port range. For media clients (for example, Office Communicator or the Live Meeting client) refer to the Media Port Range section of this document.

 
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