Socket API Versus SCTP Socket API

The SCTP APIs use the existing socket APIs to perform operations that are similar to the operating behavior of the socket APIs. For example, in the existing socket APIs and the SCTP socket APIs, an application can call the bind()() API only once and an application can specify only a single address in the bind()() API.

However, because of the unique features of SCTP, such as multistreaming and multihoming, the existing socket APIs either do not work on an SCTP socket, or the semantics of the socket APIs need modification. For example, because of the multi-homing feature supported in SCTP, the socket APIs, getsockname()() and getpeername()(), do not work on an SCTP socket if a given association is bound to multiple local addresses and the association has multiple peer addresses. Applications must use the sctp_getpaddrs()() SCTP socket API to obtain the peer addresses in an association.

Unlike the existing socket APIs, the SCTP socket APIs disclose many features of the SCTP protocol and association status to the application, to enable applications gain better control over the SCTP protocol. For example, an application can specify some of the association setup parameters, such as the number of desired outbound streams and maximum number of inbound streams, to control an association.