The Unabridged Pentium 4 IA32 Processor Genealogy

The Request Agent

The Request Agent Types

There are two types of Request Agents:

• Symmetric Request Agents— Most typically, these are the processors. With regard to FSB arbitration, the symmetric Request Agents have equal importance with respect to each other and use a rotational (symmetrical) priority scheme for FSB arbitration. Note that a custom-designed Request Agent other than a processor could be designed to operate as a symmetric agent. The symmetric agent FSB arbitration scheme supports up to but no more than four symmetric Request Agents in the rotation (eight if Hyper-Threading is enabled in four physical processors on the FSB).

• Priority Request Agents— The system designer may include one or more Request Agents that are not processors ...