Subject: [dispatch] Results of a SIPforum effort to understand problems with Fax and SIP

From: "Richard Shockey" <[email-masked]>
Date: Fri, 4 Sep 2009 16:05:53 -0400

The SIPforum has recently issued a report on ongoing issues with SIP and Fax
that may be of interest to the larger SIP community. Work on understanding
the problems with FAX and SIP are continuing and members of the IETF SIP
community are invited to participate in future discussions.

SIPforum FoIP Task Group Charter

The proposed charter of the SIP Forum FoIP task group is to investigate
ongoing issues with the deployment of fax services, specifically ITU T.38,
in SIP networks. SIP networks cannot adequately replace analog PSTN in
enterprises unless essential services such as FAX are accommodated.

The use of ITU T.37 email based store and forward has not been successful
due to the specific legal status fax enjoys in law and that fax
communications has 3rd party confirmation of transmission and/or delivery in
carrier billing records (non repudiation). Classic FAX (T.30) over G.711 has
not proved to be reliable and SIP communications , in the future, may use
other codecs that have been proven to break T.30 such as G.729 and other
high compression codecs like SPEEDEX etc.

The SIP Forum FoIP task group is chartered to accomplish the following
tasks:

1. Fully document what the current issues are surrounding ITU T.38 in SIP
networks.
a. What interoperability testing procedures currently exist.
b. What are the common factors in T.38 failure such as page length or lack
of ECM support in carrier gateways and ATA's.
c. Network packet loss considerations.

2. Determine what solutions are currently available to address the problem.

3. Determine if the problem can be solved within the scope of existing IETF
SIP and ITU T.38 Recommendations.

4. If the problems can be solved using existing standards by tightening
requirements, document the procedures vendors and carriers need to implement
in an appropriate SIP Forum Technical Recommendation.

5. If, in the judgment of the SIP Forum FoIP WG, existing IETF and or ITU
standards need to be modified, develop a strongly worded recommendation to
the appropriate Standards Development Organization (SDO) on what the SIP
Forum FoIP WG has discovered and recommend appropriate action by the SDO to
remedy the issue.

Information about the FoIP Task Group

http://www.sipforum.org/content/view/310/252/

The Fax Problem Statement Report.

http://www.sipforum.org/component/option,com_docman/task,doc_download/gid,30
3/Itemid,75/

Richard Shockey
Member Board of Directors SIPforum
Co-Chair SIPforum Technical Task Groups

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