SCTP Team 2: Alexia Allaway Johnson Nguyen Nnamdi Nwajagu Scott Seo Audrey Stanczak Wade Whitten

What is SCTP SCTP stands for Stream Control Transfer Protocol Transport Layer Protocol Connection-oriented protocol that provides ordered transmission of messages Messages do not have to be ordered if specified SCTP provides multiple features to enhance reliability such as: Multistreaming capabilities Error Control Congestion Control Packet lifetime Protection against DoS attacks

History of SCTP RFC 2960 – October 2000 RFC 3286 – May 2002 Purpose: Introduced SCTP Category: Standards Track Authors: R. Stewart - Motorola Q. Xie – Motorola K. Morneault – Cisco Systems, Inc. C. Sharp - Cisco Systems, Inc. H. Schwarzbauer - Siemens T. Taylor - Nortel Networks I. Rytina - Ericsson M. Kalla - Telcordia L. Zhang - University of California, Los Angeles V. Paxson - Amrita Center for Industrial Research and Innovation RFC 3286 – May 2002 Purpose: Updates RFC 2960 and provides an introduction to the high-level capabilities of SCTP as a protocol Category: Informational Authors: L. Ong - Ciena Corporation J. Yoakum - Nortel Networks RFC 3309 – September 2002 Updated error checking capabilities Standards J. Stone - Stanford University R. Stewart - Cisco Systems, Inc. D. Otis - SANlight Wade

History of SCTP (cont) RFC 4460 – April 2006 Purpose: Informational Provides errors and solutions to issues discovered through the use SCTP since its start Category: Informational Authors: R. Stewart - Cisco Systems, Inc. I. Arias-Rodriguez - Nokia Research Center K. Poon - Sun Microsystems, Inc. A. Caro - BBN Technologies M. Tuexen - Muenster University of Applied Sciences RFC 4960 – September 2007 Purpose: Obsoletes RFC 2960 and RFC 3309 Category: Standards Track Author: R. Stewart – Cisco Systems, Inc. Wade

How It Works To Establish Connection: A client sends an Initiate signal to the server Server responds with an Initiate Acknowledgement containing a state cookie This cookie contains a Message Authentication Code, time stamp, and life span of the cookie Client responds with a Cookie-Echo After verifying authenticity, the server allocates resources for the association and responds with a Cookie Acknowledgement The connection is now in the established state The client sends a Shutdown signal to the server Server responds with Shutdown Acknowledgement signal Client responds with Shutdown-Complete signal Abort signal may be used if any errors occur To Terminate Connection:

SCTP Packet Source Port: Identifies the port number of the transmitting device Destination Port: Identifies the port number of the receiving device Verification Tag: 32 bit number generated to distinguish packets apart from one another Checksum: 32 bit CRC for error control Chunk Type: 8 bits to identify the chunk Chunk Flag: 8 flag bits that vary with chunk type Chunk Length: 16 bit unsigned value to specify chunk length Chunk Data: Data to be sent Padded with 0s if not a size multiple of 4

TCP vs. SCTP Like TCP, SCTP manages "reliable transport" (ensuring the complete arrival of data units that are sent over the network) over the Internet's Internet Protocol (IP), the protocol responsible for moving the data but not for managing whether all the data arrives.  Unlike TCP, SCTP ensures the complete concurrent transmission of several streams of data between connected end points.  SCTP also supports multihoming, which means that a connected end point can have alternate IP addresses associated with it in order to route around network failure or changing conditions.

Features of SCTP Message-Oriented Ensures in-sequence transportation of messages With congestion control Has the reliability of TCP while being message-driven like UDP Does not allow half-closed connections

Steaming Capabilities SCTP, TCP, and UDP TCP Transmission Control Protocol UDP User Datagram Protocol SCTP Stream Transmission Control Protocol Layer Protocol Transport Layer Protocol Connection Type Connection-Oriented Connectionless Transmission Stream-Oriented Message-Oriented Addressing  Unicast Multicast  Error Control 16 bit Check Sum None 32 bit CRC Steaming Capabilities Single Stream  Single Stream Multistreaming Flow Control Yes No Congestion Control Fault Tolerance Data Delivery Strictly Ordered Unordered Partially Ordered Security Improved Wade

https://searchnetworking.techtarget.com/definition/SCTP References https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/com.ibm.aix.networkcomm/sctp_intro.htm+ https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/com.ibm.aix.networkcomm/sctp_startup.htm https://www.ibm.com/developerworks/linux/library/l-sctp/?ca=dgr- lnxw07SCTPhttps://f5.com/resources/white-papers/introduction-to-the-stream-control-transmission-protocol https://www.juniper.net/documentation/en_US/junos/topics/concept/gprs-stream-control-transmission- protocol-understanding.html https://www.rfc-editor.org/info/rfc2960RFC https://www.rfc-editor.org/info/rfc3286 https://www.rfc-editor.org/info/rfc4460 https://www.rfc-editor.org/info/rfc4960 https://www.isoc.org/briefings/017/ https://www.networkworld.com/article/2222277/cisco-subnet/what-about-stream-control-transmission- protocol--sctp--.html https://searchnetworking.techtarget.com/definition/SCTP