Communications Programming Concepts Socket Addresses Sockets can be named with an address so that processes can connect to them. The socket layer treats an address as an opaque object.
Applications supply and receive addresses as tagged, variable-length byte strings.
A data structure called a sockaddr can be used as a template for referring to the identifying tag of each socket address. This tag is then used to identify the subroutine to invoke the desired operation. Socket Address Storage Addresses passed by an application program commonly reside in mbufs only long enough for the socket layer to pass them to the supporting protocol for transfer into a fixed-sized address structure. This occurs, for example, when a protocol records an address in a protocol control block. The sockaddr structure is the common means by which the socket layer and network-support facilities exchange addresses.