SCTP (Stream Control Transmission Protocol) operates by providing reliable, message-oriented transport services between two endpoints in a network. Here’s how SCTP works:
SCTP establishes and maintains associations between endpoints, similar to TCP connections. It supports both unicast and multicast communication. SCTP segments data into messages, each with its own sequence number for tracking and reordering at the receiving end. This allows SCTP to handle data streams independently while ensuring reliable, in-order delivery. SCTP also supports multi-homing, where each endpoint can be associated with multiple IP addresses, providing resilience against network failures.
SCTP heartbeat mechanism is used for checking the health and availability of an SCTP association between two endpoints. Heartbeats are small control messages periodically exchanged between SCTP endpoints to confirm that the connection is still active. If one endpoint stops receiving heartbeats from the other, it may initiate recovery procedures to re-establish the association or handle the failure gracefully.
SCTP controls congestion using several mechanisms similar to TCP. It includes congestion control algorithms such as slow start, congestion avoidance, fast retransmit, and fast recovery. SCTP adapts its transmission rate based on network conditions and feedback from the receiving endpoint, aiming to maintain efficient data transfer without causing network congestion or packet loss.
Process-to-process communication in SCTP involves applications communicating directly using SCTP sockets. SCTP allows multiple streams of data within a single association, enabling applications to send and receive messages independently and efficiently. Each message is delivered reliably and in sequence, ensuring that the receiving application gets data exactly as sent by the sending application.
SCTP neither uses TCP nor UDP exclusively. Instead, SCTP is a separate transport layer protocol that provides features of both TCP (reliability, congestion control) and UDP (message-oriented, support for multi-streaming). It operates independently and is identified by its own protocol number (132) in the IP protocol suite. SCTP is designed to offer improved reliability, performance, and flexibility for applications requiring robust data transmission and congestion control mechanisms.
