As part of a broader organisational restructure, data networking research at Swinburne University of Technology has moved from the Centre for Advanced Internet Architecture (CAIA) to the Internet For Things (I4T) Research Lab.

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SONATA - SCTP Over NAT Adaptation


Network Address Translation (NAT) is typically used to share a single Internet address amongst a number of users. Extending the common approach used in NAT implementations for TCP and UDP to the SCTP protocol is not viable - the SCTP protocol specification would require checksums for the whole packet (not just the header) to be re-calculated for each packet - particularly for small home router implementations. Further, SCTP also offers multi-homing which offers new challenges for the NAT code to track in a single SCTP connection.

This project entails developing a NAT implementation to support SCTP to be released for the FreeBSD 7 platform. Our release code will utilise an existing NAT framework such as ipfw or ipf such that it can be practically deployed on real systems. The NAT will track SCTP connections via the Verification Tag (VTag) field and retain connection details should one end of a multi-homed session change end-points.

The project will also test this implementation under a number of different usage and failure-mode scenarios, the results of these tests will be published and can be used to promote the use of SCTP in-the-wild.

Project Goals

  • Development and release of a BSD licensed NAT implementation to support SCTP on the FreeBSD 7 platform
  • Development of a test plan to test both the functionality and the performance of the implementation
  • Analysis of system implementation

Project Outcomes

  • SCTP NAT development and code has been incorporated into the FreeBSD source as of February 7 2009, SVN Revision 188294
  • Project source code implementation and documentation available on the Downloads page
  • Papers and presentations resulting from this project are available on the Publications page

Program Members


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This project has been made possible in part by a grant from the Cisco University Research Program Fund at Community Foundation Silicon Valley.

Last Updated: Wednesday 18-Mar-2009 14:08:28 AEDT | Maintained by: Jason But ( | Authorised by: Grenville Armitage (