Direct Communication

• Processes must name each other explicitly:

1. send (P, message) – send a message to process P
2. receive(Q, message) – receive a message from process Q

• Properties of communication link

1. Links are established automatically.
2. A link is associated with exactly one pair of communicating processes.
3. Between each pair there exists exactly one link.
4. The link may be unidirectional, but is usually bi-directional.