Service Primitive The way in which a layer provide service is by mean of primitive. A service is formally specified by a set of primitives (operations) available to user processes to access the services. These primitives tell the services to perform some action or report on an action taken by a peer entity. Some of the primitives are:   Primitive Meaning LISTEN Block waiting for an incoming connection CONNECT Establish a connection with a waiting peer ACCEPT Accept an incoming connection from a peer RECEIVE Block waiting for an incoming message SEND Send a message to the peer DISCONNECT Terminate a connection