Home > Articles > Networking

This chapter is from the book

1.4 A Short History of SCTP Development

Table 1–1 Feature Comparison Between SCTP, TCP, and UDP

Protocol Feature




State required at each endpoint




Reliable data transfer




Congestion control and avoidance




Message boundary conservation




Path MTU discovery and message





Message bundling




Multi-homed hosts support




Multi-stream support




Unordered data delivery




Security cookie against SYN flood attack




Built-in heartbeat (reachability check)




1.4.1 Early Works Before the IETF and MDTP

The work that has become SCTP began quite a number of years ago with the realization that TCP had several key weaknesses in dealing with telephone call control. The first realization came in 1991 when a network broke while testing and many minutes transpired before the TCP socket gave an error indication. This was quite unacceptable and began the quest (at least by the authors) to build something better.

Three consecutive works were started by this incident, each experimenting with methods of putting together reliable communications that used UDP. Each one attempted to escape some of the deficiencies of TCP. One of these early implementations used a continual three-way handshake, while another used a modification of this. Each improved on the other until the last, Multi-network Datagram Transmission Protocol (MDTP), began in 1997. After getting most of the general concepts together and having a working implementation, the authors decided to submit it to the IETF for consideration in 1998.

The submission of MDTP coincided with another telephony-signaling-over-IP initiative also being started in the IETF. That initiative resulted in the forming of the SIGTRAN working group in the Transport Area. At that time, the goal of SIGTRAN was to move existing telephone signaling protocols, including ISUP, DSSI, etcetera, onto a pure IP-based network.

The requirements for telephony signaling transport and the modular architecture developed by SIGTRAN found a good fit with MDTP's design concept. This began a host of modifications of the protocol in SIGTRAN, improving and refining the original design.

1.4.2 IETF Refinements

This name change evoked much discussion on the SIGTRAN mailing list as well as within the design team. The name change in many ways was more significant than many thought. It not only symbolized the substantial design improvement that the working group had performed; it signified an expansion of scope and functionality of the protocol. This expansion was what eventually led to SCTP being moved from a protocol running over UDP to one that directly runs over IP.

The following list describes some of the major changes that were invoked by the working group and the Internet Engineering Steering Group (IESG):

  • Multi-stream concept—The working group made the decision to separate the data reliability function from the message ordering function. This in effect enabled multiple ordered subflows within a single reliable connection and provided a solution to the "head-of-line blocking" problem that the original MDTP design was not able to solve.

  • Congestion control enhancements—The original MDTP design addressed congestion control incorrectly. The working group corrected this by completely redesigning most parts of the MDTP congestion control function, using both the TCP experiences learned from the past and new research results on TCP congestion control in the IETF and IRTF communities.

  • Four-way secure association initiation sequence—The original design used a modified three-way handshake initiation sequence similar to that of TCP. This was improved by the working group via the addition of the fourth "leg" to the handshake sequence and the introduction of an encrypted state cookie to fend off potential security attacks.

  • Selective acknowledgment (SACK) improvements—The SACK function was improved and enhanced from its original design so it more closely paralleled the TCP SACK extension.

  • Message bundling improvements—The original MDTP message bundling was replaced with a very efficient and flexible chunk-based message bundling mechanism by the working group.

  • Path MTU discovery—This was added to SCTP by the working group as a mandatory function in order to make SCTP more adaptive to various network conditions.

  • The large message fragmentation function was redesigned.

  • Extensibility improved—The chunk-based design and the extension mechanism were introduced to allow the IETF to add new features to the protocol in the future.

  • An enhancement was made to allow user data to be piggybacked on the third and fourth legs of the initial opening handshake sequence.

After about two years of designing and reviewing and about twenty revisions on the draft document, SCTP finally became an IETF Proposed Standard in October 2000 and was published as RFC2960 (Stewart et al. 2000). Since then, the continued work on SCTP has been handed over from SIGTRAN to the Transport Area working group (TSVWG) in the IETF.

If you would like to plumb the history of SCTP and dig through the 4,000+ e-mails that were generated during SCTP's birth, you can consult the IETF Web pages to find the current pointer to the e-mail archives of both SIGTRAN and TSVWG at http://www.ietf.org.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020