Signaling Transport

Document Charter Signaling Transport WG (sigtran)
Title Signaling Transport
Last updated 2009-03-19
State Approved
WG State Concluded
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The primary purpose of this working group will be to address the 
transport of packet-based PSTN signaling over IP Networks, taking into 
account functional and performance requirements of the PSTN signaling. 
For interworking with PSTN, IP networks will need to transport 
such as Q.931 or SS7 ISUP messages between IP nodes such as a 
Gateway and Media Gateway Controller or Media Gateway.

 Examples of such transport include:

  - transport of signaling between a Signaling Gateway and Media 
    or Media Gateway Controller
  - transport of signaling ("backhaul") from a Media Gateway to a Media
    Gateway Controller
  - transport of TCAP between a Signaling Gateway and other IP nodes

 Applications include:

  - Internet dial-up remote access
  - IP telephony interworking with PSTN
  - Other services as identified

Specific goals are:

1. Architecture and Performance Requirements: The working group will
   produce an informational RFC identifying functionality and
   performance requirements to support signaling over IP. Signaling
   messages have very stringent loss and delay requirements in the 
   existing telephone networks that need to be supported.

2- Transport: The working group will produce a standards track
   proposal or proposals defining transport of signaling protocols
   using SCTP, based on the requirements identified above.

These proposals will identify the method of encapsulation of different
signaling protocols.  This will include differentiating between 
different protocols being carried, and what components are 
translated or terminated at the SG.  Security and resilience must be 

Note: TCAP is a transaction protocol with different functions and
      requirements than call control signaling.  This will need to be
      taken into account in its mapping to IP networks.

      This work will be done in conjunction with other IETF working
      groups looking at similar issues.  The working group will also 
      ensure that good information conduits exist with groups in other
      standards groups with expertise in the relevant signaling 
      protocols or in the network requirements for the transport of 
      relevant signaling protocols.

The group will make use of existing IETF QoS and security technology 
will not address creation of new QoS or security functions for IP
networks. Nor will the working group work on defining new call control 
or device control protocols.