What is Stream Control Transmission Protocol (SCTP)?
The Stream Control Transmission Protocol (SCTP) is a transport layer protocol situated at Layer 4 of the OSI reference model, similar to TCP and UDP. Originally designed to implement signaling protocols for phone networks over IP, SCTP was standardized in 2000 as a versatile transport protocol.
SCTP has the following features:
Support for Multi-Homing:
Multi-homing refers to the use of multiple network interfaces to enhance availability. In SCTP, the communication path between two endpoints is called an "association." For example, an association can combine wired LAN and Wi-Fi, dynamically switching between networks—using wired LAN when connected and Wi-Fi otherwise.
Support for Multi-Streaming:
SCTP allows multiple streams within a single association. For instance, it can separate streams for data exchange and control, enabling faster control responses and improved real-time communication.
Protection Against SYN Flood Attacks:
TCP reserves connection resources as soon as it receives a connection request, making it vulnerable to SYN flood attacks—a DoS attack where a server’s resources are overwhelmed by forged connection requests. SCTP uses a 4-way handshake to verify the validity of the source IP address before reserving resources, reducing susceptibility to such attacks.
Preservation of Message Boundaries:
TCP operates as a byte-stream protocol and does not preserve message boundaries. UDP preserves message boundaries but does not guarantee message order. SCTP, as a message-oriented protocol, maintains message boundaries while offering optional message order guarantees.
SCTP combines the advantages of both TCP and UDP, offering high availability and real-time communication capabilities. It is already being utilized in technologies like LTE.