Packet Format: Control Packets

Table 4-1 on page 69 summarizes the HyperTransport Information, Request, and Response control packet types and the command names associated with them. Some things to note in the table:

  • For each packet variant, the virtual channel (VChan) is indicated in the second column: posted, non-posted, or response. Note: information packets do not travel in any of the virtual channels and are not subject to flow control.

  • The first byte in each control packet type contains a 6-bit Command (CMD) Code. By sending this information at the beginning of a control packet, the receiver is informed immediately of the type of packet being transferred, the number of bytes to expect, and the format of the bit fields contained within. The ...

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