Vista SP1 (or SP2) DSCP settings for QoS OC 2007 R2

Author: Martin Isaksen

Publication date: June 2009

Product version: Office Communications Server 2007 R2

In order to mark Audio and Video packets for DSCP in OC 2007 R2, the following steps has to be performed on Vista SP1 and SP2 PCs:

Create and update the following key : (32 bit DWORD set to)

  1. HKEY_LOCAL_MACHINE\Software\Microsoft\RTC\Transport\QoSEnabled
  2. Set 32 bit Dword to 1 to enable
  3. Reboot PC (this will not take effect until rebooted)

After the reboot, RTP Media will be marked with the following default values: (which can be changed)

  1. Audio calls will be marked with DSCP 40
  2. Video will be marked with DSCP 24

These default values can be changed by going to Group Policy and changing the default value show below:

Setting SIP TLS packets for specific DSCP markings

For customers who also want signaling (SIP TLS) to be marked with unique DSCP values - a group policy will have to be created. (see following steps)

1) Under Group Management Editor -- Create New Policy

2) Set Policy Name DSCP value for SIP signaling.  We will use DSCP 40 for SIP signaling per RFC 4504. 

3) Next add exact program path and name:
(c:\Program Files\Microsoft Office Communicator\communicator.exe)


4) Next all (i.e any) IPs will be used as the filter 


5) Next select TCP 5061 as the destination port.  (SIP TLS uses TCP 5061)


6) Click finish and you are done! 


This insight into Office Communications Server 2007 R2 was created as part of Martin Isaksen's participation in the Microsoft Certified Master program.

The Microsoft Certified Master Program: The Microsoft Certified Master: Microsoft Office Communications Server 2007 program provides the most in-depth and comprehensive training available today for Office Communications Server 2007. This three-week training program is delivered by recognized experts from Microsoft and Microsoft partner organizations. 

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Comments (1)
  1. Vista SP1 (or SP2) DSCP settings for QoS OC 2007 R2
    thank you

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