MSRP Relay and MSRP Chat server

http://msrprelay.org/chrome/site/files/scenario-simple.png

This project implements:

  • MSRP relay, which is an extension to the MSRP protocol. Its main role is to help NAT traversal of IM and file transfer media sessions between SIP User Agents located behind NAT. This project implements an MSRP relay, which is an extension to the MSRP protocol. Its main role is to help NAT traversal of media sessions between endpoints located behind NAT. This extension is defined in RFC 4976.
  • MSRP chat server, which allows multi-party IM/File transfer sessions using SIP protocol draft-ietf-simple-chat-02

Background

A series of related instant messages between two or more parties can be viewed as part of a "message session", that is, a conversational exchange of messages with a definite beginning and end. This is in contrast to individual messages each sent independently. Messaging schemes that track only individual messages can be described as "page-mode" messaging, whereas messaging that is part of a "session" with a definite start and end is called "session-mode" messaging.

Page-mode messaging is enabled in SIP via the SIP MESSAGE method, as defined in RFC 3428. Session-mode messaging has a number of benefits over page-mode messaging, however, such as explicit rendezvous, tighter integration with other media-types, direct client-to-client operation, and brokered privacy and security.

Message Session Relay Protocol (MSRP) is a protocol for transmitting a series of related instant messages in the context of a session. Message sessions are treated like any other media stream when set up via a rendezvous or session creation protocol such as the Session Initiation Protocol (SIP). MSRP Sessions are defined in RFC 4975.

Security

The servers have the following security features:

  • TLS encryption and digital certificates using GnuTLS library
  • Digest or basic HTTP authentication with support for multiple realms
  • Database passwords can be stored in an encrypted format

Documentation

Download

The software can be downloaded from:

http://download.ag-projects.com/MSRPRelay/

The software is provided under GPL license.

MSRP clients

One of the reasons for the development of MSRP relay was to kick start the development of MSRP clients. We are not aware of any client at the moment of writing of this wiki page. A working proof-of-concept Test client for a file transfer session between two endpoints located behind NAT is available under the test directory of the tar archive.

Live testbed

We provide a live SIP testbed with MSRP relay enabled. You may use the SIP accounts registered at http://sip2sip.info for reserving MSRP sessions in an operational MSRP relay. 

_msrps._tcp.sip2sip.info. 300   IN      SRV     0 0 2855 node03.dns-hosting.info.
node03.dns-hosting.info. 60     IN      A       81.23.228.146

Note: Relaying traffic through http://sip2sip.info, which is free service, uses bandwidth and there is no limit for a file transfer session. The relay does not feature yet throttling of sessions, which is on the TODO list. For the benefit of other test users, please refrain yourself from abusing the test bed by transferring only small files or use the relay for IM sessions only.

Credits

  • Funding: NLNet foundation
  • Project management: Adrian Georgescu
  • Authors: Ruud Klaver, Denis Bilenko
  • Contributors: Dan Pascu's python-gnutls
  • Many thanks to the IETF community for advise and support

Support

  • The project is supported via this wiki collaboration system by AG Projects. To open ticket please Register first. The ticketing support system is available only for registered users. The support is provided on a best-effort basis.
  • For interaction between MSRP Relay and OpenSER you may consult the OpenSER users mailing list

Commercial products

MSRPRelay is part of turnkey SIP platforms offered by AG Projects:

http://www.ag-projects.com/Products