PCI Express Base Specification v1.0 - 2002.pdf

PCI EXPRESS BASE SPECIFICATION, REV. 1.0Requester IDRoot ComplexRoot PortSequenceThe combination of a Requester's Bus Number, Device Number, andFunction Number that uniquely identifies the Requester. In most cases,a PCI Express bridge or Switch forwards Requests from one interface toanother without modifying the Requester ID. A bridge from a bus otherthan PCI Express (including a PCI bus operating in conventional mode)must store the Requester ID for use when creating a Completion for theRequest.An entity that includes a Host Bridge and one or more Root Ports.A PCI Express Port, on a Root Complex, that maps a portion of the PCIExpress interconnect Hierarchy through an associated virtual PCI-PCIBridge.A single Request and zero or more Completions associated with carryingout a single logical transfer by a Requester.Standard Hot-PlugController (SHPC) A PCI hot-plug controller compliant with SHPC 1.0.Split Transaction A single logical transfer containing an initial transaction (the SplitRequest) that the target (the completer or a bridge) terminates with SplitResponse, followed by one or more transactions (the Split Completions)initiated by the completer (or bridge) to send the read data (if a read) or acompletion message back to the requester.SwitchA Switch connects two or more Ports to allow Packets to be routed fromone Port to another. To configuration software, a Switch presents theappearance of an assemblage of PCI-to-PCI Bridges.SymbolA 10 bit quantity produced as the result of 8b/10b encoding.Symbol Time The period of time required to place a Symbol on a Lane (ten times theUnit Interval).TagA number assigned to a given Non-posted Request to distinguishCompletions for that Request from other Requests.TBDTo be defined by PCI-SIG.Transaction DescriptorAn element of a Packet header that, in addition to Address, Length, andType, describes the properties of the Transaction.TLP orTransaction Layer PacketA Packet generated in the Transaction Layer to convey a Request orCompletion.Transaction Layer The outermost layer of the PCI Express architecture that operates at thelevel of transactions (for example, read, write).TransceiverThe physical transmitter and receiver pair on a single chip.TransmitterThe component sending Packet information across a Link is theTransmitter.Unsupported Request,URA Request Packet that specifies some action or access to some spacethat is not supported by the Target.24