Modify bandwith reserved for QoS-aware programs

Posted in Windows XP by Community Submission

Traffic flow can be managed very well in Windows XP using the Quality of Service (QoS) Resource Reservation Protocol (RSVP). However, programs must be designed to take advantage of this QoS API. The traffic from programs that are not QoS-aware are sent directly to a different API called TCI. These programs have to fight for bandwidth because unlike the QoS API, there is no bandwidth reservation. If you use a lot of QoS-aware programs and would like to change the percent of the bandwidth that is reserved for the program, read below.
  1. Make sure your logged on as Administrator. Do not log on with any account that just has administrator privileges.
    To log in as Administrator:
    - Click on start->logoff->logoff
    - At the logon screen hold Ctrl+Alt+Del.
    - In the user field type 'Administrator'
    - In the password field type the password for the administrator (if you don't have one leave blank) and press OK
  2. Click on the Start button and select run.
  3. Type gpedit.msc in the text box and click OK
  4. Once the program loads, expand the Computer configuration branch.
  5. Expand the Administrative templates branch.
  6. Expand the Network branch.
  7. Highlight the QoS Packet Scheduler in left window.
  8. In right window double click the limit reservable bandwidth setting
  9. On setting tab check the enabled option.
  10. Where it says Bandwidth limit %, change it to read what ever percent you want to reserve for QoS-aware applications.
  11. Click OK and exit the group policy editor.
  12. Go to your Network connections (start->my computer->my network connection-> view network connections).
  13. Right click on your connection, choose properties then under the General or the Networking tab (where it lists your protocols) make sure QoS packet scheduler is enabled.
  14. Now just reboot your computer and you are all done.

When a QoS-aware program is in use it will reserve the allocated amount of bandwidth and that will take away form other non QoS-aware programs. However, once the QoS-aware application is closed or closes the network connection, the bandwidth reservation is released. This is done by a series of PATH and RESV refresh messages sent back and fourth over the connection. Once these messages are no longer detected, the data flow is closed and the reservation of bandwidth is eliminated.

For more information on QoS Traffic Control: Click Here

For more information on the control of reservation of bandwidth: Click Here

Original Tweak was written by BigBrother but was rewritten after it was found to be incorrect.

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