Stream Control Transmission Protocol
The Stream Control Transmission Protocol (SCTP) defined in RFC 2960 is a modification of TCP. Like TCP, SCTP offers a reliable, flow-controlled, connection-oriented service for data streams. SCTP differs from TCP in that it defines independent, unidirectional data flows between hosts. Two such flows are needed for a full-duplex dialog.
The principal feature of SCTP that makes it attractive to the SS7 environment is its multihoming capability. A single traffic flow can be split between multiple destination IP addresses, allowing a capability similar to that found on the A links between a signaling point and a signaling transfer point (STP). Traffic is shared between the A links during call setup and termination. The connection is maintained even though the traffic is sent via different interfaces. SCTP allows the same capability in an IP environment. An IP-based SCP could receive a single data flow on different IP interfaces to the network.
The error recovery mechanisms found in SCTP support corrections from path failures, out-of-sequence packets, and lost packets.