Editing HyperTransport (section)

===Packet-oriented===
HyperTransport is [[Packet (information technology)|packet]]-based, where each packet consists of a set of [[32-bit]] words, regardless of the physical width of the link. The first word in a packet always contains a command field. Many packets contain a 40-bit address. An additional 32-bit control packet is prepended when 64-bit addressing is required. The data payload is sent after the control packet. Transfers are always padded to a multiple of 32&nbsp;bits, regardless of their actual length.

HyperTransport packets enter the interconnect in segments known as bit times. The number of bit times required depends on the link width.  HyperTransport also supports system management messaging, signaling interrupts, issuing probes to adjacent devices or processors, [[I/O]] transactions, and general data transactions.  There are two kinds of write commands supported: posted and non-posted. Posted writes do not require a response from the target. This is usually used for high bandwidth devices such as [[uniform memory access]] traffic or [[direct memory access]] transfers. Non-posted writes require a response from the receiver in the form of a "target done" response. Reads also require a response, containing the read data. HyperTransport supports the PCI consumer/producer ordering model.