2.2.5.6 QosQueryResp Upper-Level Header Format
A sink sends the QosQueryResp frame to the controller, in response to a QosQuery frame. It lists QosProbe events (also known as QosEventDesc structures) that have been observed since the previous QosQuery frame. QosQueryResp frames MUST NOT be acknowledged. The Base header's Identifier field of the QosQueryResp MUST match the QosQuery frame that is generated in response to the QosQueryResp frame. The ordering of QosEventDesc items in this frame MUST represent the ordering of the arrival time.
The QosQueryResp header that follows the Base header MUST have the following format.
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Num Events |
QosEventDesc list (variable) |
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R (1 bit): This field MUST be set to 0x00 and MUST be ignored upon receipt.
E (1 bit): This field MUST be set if the responder is unable to allocate enough memory for one or more QosEventDesc structures.
Num Events (14 bits): This field specifies the count, in network byte order, of QosEventDesc items that follow. If the E bit is set, this field MUST be zero.
QosEventDesc list (variable): This field specifies a set of QosEventDesc items, where each QosEventDesc item is an 18-octet structure. If the Num Events field is zero, this field MUST NOT be present.
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1Controller_Transmit_Timestamp
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Sink_Receive_Timestamp
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Packet_ID
Reserved
Controller_Transmit_Timestamp (8 bytes): This field specifies the time stamp, in network byte order, of the controller on event transmission in units per Performance Counter Frequency.
Sink_Receive_Timestamp (8 bytes): This field specifies the time stamp, in network byte order, of the sink on event reception in units per Performance Counter Frequency.
Packet_ID (1 byte): This field specifies the value of the Packet ID field from the QosProbe frame that generated the event.
Reserved (1 byte): This field is not currently used, but it exists only to pad the structure to an even size. This field MUST be set to 0 on transmit and ignored on receipt.