Quality of Service

The originator of a call on an SVC can specify quality of service (QoS) parameters for the call that specify performance parameters for the call. Depending on the signaling protocol that is being used, a call manager or MCM driver that is setting up an outgoing or incoming call can negotiate the QoS with a network entity such as a network switch or a remote client. If allowed by the signaling protocol, a connection-oriented client might also request a change of QoS when determining whether to accept an incoming call.

The QoS parameters for a call are specified as call parameters in a CO_CALL_PARAMETERS structure. CO_CALL_PARAMETERS points to two other structures:

  • CO_CALL_MANAGER_PARAMETERS, which specifies call manager parameters that a call manager or MCM driver use to set up a call.

  • CO_MEDIA_PARAMETERS, which specifies media parameters that a miniport driver or MCM driver use to activate a VC.

Both CO_CALL_MANAGER_PARAMETERS and CO_MEDIA_PARAMETERS contain generic parameters (flags) that apply to all drivers that use the parameters. Each of these structures also points to a CO_SPECIFIC_PARAMETERS structure that specifies call manager-specific parameters (when pointed to by a CO_CALL_MANAGER_PARAMETERS structure) or media-specific parameters (when pointed to by a CO_MEDIA_PARAMETERS structure).

For more information about QoS operations, see Client-Initiated Request to Change Call Parameters and Incoming Request to Change Call Parameters.