The X.25 protocol that forms packets and manages packet exchanges between physical data terminal equipment (DTE) across a network of virtual circuits. PLP also can run on LANs and ISDN interfaces running link access procedure on the D channel (LAPD). PLP is responsible for call setup, synchronization, data transfer, and call clearing. In data transfer mode, PLP transfers data between DTE across both permanent virtual circuits (PVCs) and switched virtual circuits (SVCs), segmenting data blocks on the transmit side and reassembling them on the receive side of the communication. PLP also handles bit padding, flow control, and error control. PLP maps into Layer 3, the Network Layer, of the OSI Reference Model. Figure P-4 illustrates the PLP packet and its constituent fields, which are as follows:
(Presentation Level Protocol) A North American standard protocol for videotex.