What is SCTP?
SCTP (Stream Control Transmission Protocol) is a transport-layer protocol that combines the reliability of TCP with multi-streaming and fault tolerance. Originally developed for telephony signaling (SS7 over IP), it has found applications in other areas as well.
Why It Matters
SCTP enables:
- Multiple independent streams within a single connection
- Multihoming: backup IP addresses and interfaces
- Packet delivery and ordering control
Unlike TCP, a delay or loss in one stream in SCTP does not block others.
Use Cases
- NGN and LTE signaling networks (Diameter, HSS)
- Routers with multihoming support
- Mission-critical systems with path redundancy
Comparison: SCTP vs TCP vs UDP
| Feature | SCTP | TCP | UDP |
|---|---|---|---|
| Data Streams | Multiple | Single | Single |
| Reliability | Yes | Yes | No |
| Delivery Order | Yes | Yes | No |
| Multihoming Support | Yes | No | Limited |
| Transmission Type | Message-oriented | Byte stream | Datagrams |
Conclusion
SCTP is a powerful yet underutilized protocol that combines the flexibility of TCP with the structure of UDP. In environments requiring multi-streaming, fault tolerance, and strict control, SCTP offers significant advantages.
