Berkeley Sockets

REFERENCE: [Stevens, Chapter 6].

This is a user API from BSD Unix (ca. 1982). An alternative is the Transport Layer Interface (TLI) from System V (ca. 1986), and modeled after the OSI model [Stevens, Chapter 7]. To access these libraries, you compile your program as follows:

 

Here is how the server-client would be implemented using Berkeley sockets. There are two versions, depending on whether the communication is connection-oriented or not:

CONNECTION-BASED SERVER:

A.

 socket()

B.

 bind()

C.

 listen() (cf. step b in client)

D.

 accept() (cf. step b in client)

E.

 read() (cf. step c in client)

F.

 write() (cf. step d in client)

CONNECTION-BASED CLIENT:

a.

 socket()

b.

 connect() (cf. steps C and D in server)

c.

 write() (cf. step E in server)

d.

 read() (cf. step F in server)

CONNECTIONLESS SERVER:

A.

 socket()

B.

 bind()

C.

 recvfrom() (cf. step c in client)

D.

 sendto() (cf. step d in client)

CONNECTIONLESS CLIENT:

a.

 socket()

b.

 bind()

c.

 sendto() (cf. step C in server)

d.

 recvfrom() (cf. step D in server)

Note that only the connection-based client skip the bind() step. Below we try to explain this.