An Introduction to the Stream Control Transmission Protocol (SCTP)
RFC 3286
Document | Type |
RFC - Informational
(May 2002; No errata)
Was draft-ong-sigtran-sctpover (individual in tsv area)
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Authors | John Yoakum , Lyndon Ong | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3286 (Informational) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Scott Bradner | ||
IESG note | Responsible: RFC Editor | ||
Send notices to | <yoakum@nortelnetworks.com> |
Network Working Group L. Ong Request for Comments: 3286 Ciena Corporation Category: Informational J. Yoakum Nortel Networks May 2002 An Introduction to the Stream Control Transmission Protocol (SCTP) Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document provides a high level introduction to the capabilities supported by the Stream Control Transmission Protocol (SCTP). It is intended as a guide for potential users of SCTP as a general purpose transport protocol. 1. Introduction The Stream Control Transmission Protocol (SCTP) is a new IP transport protocol, existing at an equivalent level with UDP (User Datagram Protocol) and TCP (Transmission Control Protocol), which provide transport layer functions to many Internet applications. SCTP has been approved by the IETF as a Proposed Standard [1]. The error check algorithm has since been modified [2]. Future changes and updates will be reflected in the IETF RFC index. Like TCP, SCTP provides a reliable transport service, ensuring that data is transported across the network without error and in sequence. Like TCP, SCTP is a session-oriented mechanism, meaning that a relationship is created between the endpoints of an SCTP association prior to data being transmitted, and this relationship is maintained until all data transmission has been successfully completed. Unlike TCP, SCTP provides a number of functions that are critical for telephony signaling transport, and at the same time can potentially benefit other applications needing transport with additional performance and reliability. The original framework for the SCTP definition is described in [3]. Ong & Yoakum Informational [Page 1] RFC 3286 SCTP Overview May 2002 2. Basic SCTP Features SCTP is a unicast protocol, and supports data exchange between exactly 2 endpoints, although these may be represented by multiple IP addresses. SCTP provides reliable transmission, detecting when data is discarded, reordered, duplicated or corrupted, and retransmitting damaged data as necessary. SCTP transmission is full duplex. SCTP is message oriented and supports framing of individual message boundaries. In comparison, TCP is byte oriented and does not preserve any implicit structure within a transmitted byte stream without enhancement. SCTP is rate adaptive similar to TCP, and will scale back data transfer to the prevailing load conditions in the network. It is designed to behave cooperatively with TCP sessions attempting to use the same bandwidth. 3. SCTP Multi-Streaming Feature The name Stream Control Transmission Protocol is derived from the multi-streaming function provided by SCTP. This feature allows data to be partitioned into multiple streams that have the property of independently sequenced delivery, so that message loss in any one stream will only initially affect delivery within that stream, and not delivery in other streams. In contrast, TCP assumes a single stream of data and ensures that delivery of that stream takes place with byte sequence preservation. While this is desirable for delivery of a file or record, it causes additional delay when message loss or sequence error occurs within the network. When this happens, TCP must delay delivery of data until the correct sequencing is restored, either by receipt of an out-of-sequence message, or by retransmission of a lost message. For a number of applications, the characteristic of strict sequence preservation is not truly necessary. In telephony signaling, it is only necessary to maintain sequencing of messages that affect the same resource (e.g., the same call, or the same channel). Other messages are only loosely correlated and can be delivered without having to maintain overall sequence integrity. Another example of possible use of multi-streaming is the delivery of multimedia documents, such as a web page, when done over a single session. Since multimedia documents consist of objects of different sizes and types, multi-streaming allows transport of these components Ong & Yoakum Informational [Page 2] RFC 3286 SCTP Overview May 2002 to be partially ordered rather than strictly ordered, and may result in improved user perception of transport.Show full document text