Browse Prior Art Database

A new SCTP chunk bundling method to minimize effect of packet losses on stream delivery

IP.com Disclosure Number: IPCOM000012877D
Original Publication Date: 2003-Jun-05
Included in the Prior Art Database: 2003-Jun-05
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Abstract

Disclosed is a method to bundle SCTP data chunks in the presence of multiple streams so as to minimize the effect of packet losses on stream delivery thereby preserving stream independence.

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  A new SCTP chunk bundling method to minimize effect of packet losses on stream delivery

SCTP - Stream Control Transmission Protocol is a new transport protocol described in RFC 2960. SCTP is a protocol that preserves message boundaries unlike TCP which sends data as a stream of bytes.

Each SCTP association can support multiple streams of data. SCTP offers sequenced delivery of user messages within a stream. SCTP uses a Stream Sequence Number (SSN) to order data within a stream. In addition, SCTP also assigns a Transmission Sequence Number (TSN) to each user data fragment or unfragmented message. The TSN is independent of any stream sequence number assigned at the stream level. The receiving end acknowledges all TSNs received, even if there are gaps in the sequence. In this way reliable delivery is kept functionally separate from sequenced stream delivery.

The multi-streaming concept can be used to transfer independent data as "logically" independent streams. For example if two JPEG images need to be sent over an SCTP association they can be sent over different streams so that any loss of data belonging to one stream (image) does not affect the delivery of data in the other stream (image).

In SCTP data is transmitted as chunks where each data chunk generally corresponds to a message or a fragment of message. Normally during transmission the SCTP sender bundles multiple user messages to fully utilize the available bandwidth. Bundling small messages at transmission helps improve the bandwidth usage efficiency of the network. However, bundling of smaller messages...