21 Oct 2007

TCP and UDP are Old !! So, What's NEW ?

TCP and UDP are Old !!
So, What's NEW ?

SCTP - Stream Control Transmission Protocol.

In the field of computer networking, the IETF Signaling Transport (SIGTRAN) working group defined the Stream Control Transmission Protocol (SCTP) as a transport layer protocol in 2002. RFC 2960 defines the protocol, with RFC 3286 providing an introductory text.These are used to connect distributed applications and allow messages to flow between them. These protocols have been used successfully to build Internet applications as we know them: e-mail, HTTP, name services and so forth. But, these protocols are very old, and over time, some of their deficiencies have become well known. The central motivation behind SCTP is to provide a more reliable and robust protocol than either TCP or UDP that can take advantage of features such as multihoming.

As a transport protocol, SCTP operates analogously to TCP or UDP. Indeed it provides some similar services as TCP—ensuring reliable, in-sequence transport of messages with congestion control. (In the absence of native SCTP support, it may sometimes be desirable to tunnel SCTP over UDP.

Whereas TCP transports a byte-stream, SCTP can transport multiple message-streams. All bytes sent in a TCP connection must be delivered in that order, which requires that a byte transmitted first must safely arrive at the destination before a second byte can be processed even if the second byte manages to arrive first. If an arbitrary number of bytes are sent in one step and later some more bytes are sent, these bytes will be received in order, but the receiver can not distinguish which bytes were sent in which step. SCTP in contrast, conserves message boundaries by operating on whole messages instead of single bytes. That means if one message of several related bytes of information is sent in one step, exactly that message is received in one step.

Read further at:
1. http://interactive. linuxjournal. com/article/ 9748
2. Linux For You Sept 2007 issue.
3. http://en.wikipedia .org/wiki/ Stream_Control_ Transmission_ Protocol
4. Unix N/w Programming - Richard Steven - Vol 1, 3rd Ed.


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