Digital Data Communications Message Protocol
Digital Data Communications Message Protocol (DDCMP) is a network protocol that was developed by Digital Equipment Corporation in 1974 to enable communication over point-to-point links for the DECnet Phase I network protocol.
The Digital Data Communications Message Protocol , or DDCMP for short , is an older, character-oriented protocol . It is still important, but is increasingly being replaced by more powerful, bit-oriented protocols such as HDLC (High-Level Data Link Control) and SDLC (Synchronous Data Link Control) .
DDCMP can be used on synchronous and asynchronous lines, in half and full duplex operation , as well as in point-to-point and multipoint connections.
It uses three classes of blocks for information, maintenance and monitoring. Error checking is carried out separately for the header and user data . The protocol is byte-count-oriented, which means that the byte length is specified explicitly in the header.
The protocol belongs to the data link layer and is therefore part of the OSI layer model .