SCTP: Stream Control Transport Protocol Albert Phouangaphay Alejandra Coca Devin Syas Dominic Ajagba Michael Gibson Zach Windon

Strategy Overview: Topics: Explain how we will cover SCTP Devin: 2 minutes Topics: What is SCTP? Albert: 3 minutes Main Features of SCTP (3 parts) Michael: 3 minutes Dominic: 3 minutes Alejandra: 3 minutes Pros and Cons of SCTP Zach: 3 minutes Conclusion Devin: 3 minutes Strategy

Introduction

What is SCTP? Message-oriented Transport-level Protocol Similarities to TCP Unicast, connection-oriented protocol Sequential packet delivery Rate-adaptive congestion control Capable of handling multiple simultaneous streams Provides for multihoming

History Doubt in TCP began in 1991 Attempts for reliable communication over UDP began MDTP began in 1997 and was submitted to the IETF in 1998 SIGTRAN formed to move telephone signaling protocols to IP Defined in RFC 2960, October 2000 Updated by RFC 4960, September 2007

Main Features of SCTP

Unicast With Multicast Properties Point-to-point protocol but can use several addresses at the same end host Uses different paths to reach the end host TCP breaks if the transport path breaks, unless the IP protocol corrects it

Reliable Transmission Uses checksums and SACK to detect corrupted, damaged, discarded, duplicated and reordered data Can retransmit data as necessary More resilient than TCP about reordered data Faster pickups

Message Oriented Similar to how UDP transports messages Each message can be framed to keep tabs on the structure and order of the datastream

Rate Adaptive Cooperates and co-exists with TCP for bandwidth Scales up and down based on network load conditions (like TCP) Same algorithms for slow starting if packets lost

Multi-homing Main difference to TCP End-node can be reachable by more than one transport address If system fails, traffic is redirected to another path TCP: SCTP:

Multi-streaming SCTP stands for Stream Control Transmission Protocol Data is sent in multiple streams, each one with an identifier Losing one stream does not affect the others TCP only uses one stream

Association Initiation To initiate communication 4 messages are used: INIT: client sends initiation message for association INI-ACK: server sends message to show the first one reached and adds a cookie (connection identifier) COOKIE-ECHO: client replies with same cookie COOKIE-ACK: server organizes resources and answers with message INIT collision resolution to avoid several simultaneous SCTP connections

Pros and Cons of SCTP

Pros With SCTP’s multihoming feature, network failures or changing conditions in the network can be dealt with by routing around the issues SCTP has reliable transport, meaning that all the data units sent through the network will make it to the desired end point SCTP can have multiple streams of data at the same time in between two endpoints that have a connection in a network

Cons SCTP requires changes in the transport stack, applications may need modification to operate SCTP rather than TCP or UDP Applications also may need to be modified to be able to handle multiple streams going simultaneously SCTP has not yet been fully implemented in some operating systems like Microsoft operating systems

Conclusion

Real World Application Used as an alternative to TCP and UDP for more secure transport with more features available Widely used in the telecom industry All major operating systems have SCTP implementation

Comparison table between SCTP, TCP and UDP

Future of SCTP Demand for SCTP is increasing due to its wider variety of services compared to conventional protocols Most likely will not beat TCP because the extra features are not worth overcoming implementation issues Several unique attributes built in to SCTP on the transport layer can be emulated in TCP on the application layer Reference Randall Stewart Isoc.org Give multi-homing example

Sources https://www.networkworld.com/article/2222277/cisco-subnet/what-about-stream-control-transmission-protocol--sctp--.html http://www.informit.com/articles/article.aspx?p=24386&seqNum=5 https://searchnetworking.techtarget.com/definition/SCTP https://www.isoc.org/briefings/017/