SCTP is a connection-oriented transport protocol that overcomes some of the limitations of both TCP and UDP that prevent reliable transfer of data over IP-based networks (such as those used by telephony systems and carrier networks). The ‘Stream’ in SCTP refers to the sequence of user messages or packets that are considered at the same time to be individual objects and also treated as a whole by networked systems. SCTP is less vulnerable to congestion and flooding due to more advanced error handling and flood protection built into the protocol.
|State required at each endpoint||yes||yes||no|
|Reliable data transfer||yes||yes||no|
|Congestion control and avoidance||yes||yes||no|
|Message boundary conservation||yes||no||yes|
|Path MTU discovery and message fragmentation||yes||yes||no|
|Multi-homed hosts support||yes||no||no|
|Unordered data delivery||yes||no||yes|
|Security cookie against SYN flood attack||yes||no||no|
|Built-in heartbeat (reachability check)||yes||no||N/A|
All of these features are built into the design of the Protocol, and the structure of SCTP packets and networks. The FortiGate unit interprets the traffic and provides the necessary support for maintenance and verification features, but the features are not FortiGate specific. These features are documented in greater detail below.