OC traffic classification RRS feed

  • Question


    The default UDP/TCP port range used by the Office Communicator 2007 client is 1024-65535. The Real Time Media Communications stack in Office Communicator 2007 allocates the media port dynamically in this range.


    Have you got guys any good idea or guide how to calssify the client to client traffic with this stange whole range which could overlap with other services?


    Thanks a lot!

    Thursday, January 31, 2008 2:31 PM

All replies

  • Microsoft UC natively supports DiffServ


    Microsoft UC natively supports DiffServ through DSCP marking by the end-points, which can easily be turned on or off and modified through Group Policies.


    When enabled, Microsoft Office Communicator 2007 instructs the transport layer of the operating system to set by default the Differentiated Services Code Point (DSCP) for voice media to the Expedited Forwarding class marking, and to set the DSCP for video media to Class 3 of Assured Forwarding. That means that for networks honoring the DSCP marking, voice is prioritized higher than video by default. These default settings ensure that on any network honoring end-point marked DiffServ, both the voice and the video media would take advantage of the network capability for DiffServ prioritization as soon as the administrator would have enabled the packet marking


    DiffServ QoS DSCP marking of packet by the end-point can be turned on by modifying or creating the following registry key to the REG_DWORD value of 1:

    HKEY_LOCAL_MACHINE \SOFTWARE \Microsoft \RTC \Transport \QoSEnabled "



    Tuesday, March 11, 2008 10:33 PM
  • Hi everyone, I'm clearly doing something silly here:

    I've created the registry key on the client pc with communicator 2007 as described, our GPO's are configured as per MS documentation:

    HKEY_LOCAL_MACHINE \SOFTWARE \Microsoft \RTC \Transport \QoSEnabled = 1 (DWORD) , i have restarted, made a call and captured the traffic and see no impact at all, DSCP markings stick at zero for communicator traffic, i believe it should be 40 for udp voice traffic after this registry entry is enabled.

    Anyone got this to seat? I Can only assume i'm doing something very dumb. Additionally i reviewed this posting: http://social.msdn.microsoft.com/forums/en-US/networkqosqwave/thread/d40deb2d-8e3d-4c0e-8011-7de63a267b6a/

    Does the OCS server need to have this enabled in order to witness the dscp markings in a packet capture? as i didnt want to do that till after hours.

    Any guidance appreciated.


    Wednesday, February 25, 2009 4:31 PM
  • The setup is definitely simple.  Make sure QOS Packet Scheduler service is installed on the network adapter you are using on the client machine.  Set the registry key as you have above.  Perhaps the RSVP service should alrady be running (but I haven't confirmed that yet).

    But one more thing.  Where is your packet sniffer?  Cisco and Nortel managed switches will set the DSCP bit back to 0 for untrusted traffic, which the MOC traffic surely is.  That is to prevent opportunistic users from prioritizing their internet radio, and so on. 

    I have not yet figured out how I am going to resolve this issue in our company.  We may either run without QOS, or bite the bullet and trust that users won't figure out a way to game the system. 

    I hope this is helpful to someone.
    Wednesday, June 10, 2009 8:33 PM