Message-oriented Communication

Message Oriented Communication (Socket)

• A socket is a communication end point to which an application can write data that are to be sent out over the underlying network, and from which incoming data can be read.

• A socket forms an abstraction over the actual port that is used by the local operating system for a specific transport protocol.

• Common operations include:

  • socket: create a new communication end point

  • bind: attach a local address to a socket

  • listen: tell operating system what the maximum number of pending connection requests should be

  • accept: block caller until a connection request arrives

  • connect: actively attempt to establish a connection

  • send: send some data over the connection

  • receive: receive some data over the connection

  • close: release the connection

Message-Passing Interface (MPI)

• MPI is designed for parallel applications and as such is tailored to transient communication.

• Support different network protocol stacks.

• Common operations include:

  • MPI_bsend: append outgoing message to a local send buffer (transient asynchronous communication)

  • MPI_send: send a message and wait until copied to local or remote buffer

  • MPI_ssend: send a message and wait until transmission starts (synchronous communication)

  • MPI_sendrecv: send a message and wait for reply (strongest form of synchronous communication)

  • MPI_isend: pass reference to outgoing message, and continue

  • MPI_issend: pass reference to outgoing message, and wait until receipt starts

  • MPI_recv: receive a message; block if there is none

  • MPI_irecv: check if there is an incoming message, but do not block