Windows XP and Windows Server 2003 turn off the RSVP
signaling in their QoS implementation. Windows Server 2003 also removes the QoS
Admission Control Service (ACS) component.
Effects on QoS Program Developers
� | The Winsock GQoS semantic remains fully supported and
unchanged. However, no RSVP message exchange is generated from GQoS calls. As
soon as the GQoS semantics and parameter checks are passed, the program enters
a state as if the RSVP signaling were completed successfully. The conforming
outgoing packets are marked according to the service level that is specified in
the requesting FLOWSPEC structure. |
� | No QoS events are posted to the program. For example,
asynchronous SIO_GET_QOS never completes. However, asynchronous SIO_SET_QOS
completes after the traffic-control functionality has been completed. This is
the same as in Windows 2000. Because RSVP messages are turned off, program
logic must not depend on receiving any specific RSVP messages. For the same
reason, "Application-ID" and "Sub-Application-ID" are not useful. |
� | On Windows Server 2003, synchronous SIO_GET_QOS returns
immediately with success and 0 bytes of data. Asynchronous SIO_GET_QOS is
pending until the socket is closed. At this time, it is completed with an
"abort" error. |
� | IP_TOS is deprecated as a way to mark packets by GQoS.
Developers can continue to use GQoS for new programs if they must mark
packets. |
� | There is no change from Windows 2000 in the Traffic Control
API implementation. Only local administrators can run Traffic Control APIs.
This is the same requirement as on Windows 2000. |
� | If RSVP messages are received on Windows XP, they are
silently dropped; no ICMP error message is returned. If RSVP messages are
received on Windows Server 2003, ICMP error messages are returned. |
Effects on QoS Administrators
� | ACS no longer exists on Windows Server 2003. The RSVP
service still runs on the host as a conduit between program and traffic-control
components. However, no RSVP messages are generated. |
� | GQoS programs can mark packets without ACS policy approval.
Note that traffic-control programs can mark packets on Windows 2000, Windows
XP, and Windows Server 2003. Older programs that use the IP_TOS socket option
can mark packets on Microsoft Windows NT 4.0. Administrators must manage these
types of programs in their networks appropriately for their network and program
requirements. |