Fax is Dead…Long Live FoIP!

By Marc Robins, SIP Forum Managing Director

Many pundits predicted that fax was dead several years ago, so it might surprise you to know that due to a host of federal and state regulations (in the U.S. at least) that require that documents be transmitted via fax, including HIPAA (the Health Insurance Portability and Accountability Act) and Sarbanes Oxley, fax is alive and well.

However, as service provider networks migrate en masse to an IP infrastructure, and enterprises follow suit, the reliability of fax transmission has suffered. With FoIP, there is an unacceptably high degree of transmission failure (around two out of every 10 pages fail to transmit.) What this means is that out of ten 1-page fax transmissions, two attempts will fail. However, it gets much worse when you are trying to send 10 ten-page faxes - the likelihood that each fax transmission will experience issues is extremely high.

As a result, another area that the SIP Forum is focusing on other than SIP trunking and User Agent configuration - an area that also desperately needs industry consensus around technical interoperability -- is Fax over IP. In short, the FoIP marketplace is ripe for an industry-approved technical recommendation that spells out the technical method to ensure that Fax works reliably over an IP network. 

Key Issues

1. G.711 Fax Reliability: The ITU-T T.38 FoIP protocol standard overcame many of the issues experienced when transmitting fax over G.711. However, many Service Providers use VoIP Gateways that do not support T.38. Instead, these carriers pass fax traffic through their network using G.711. Fax traffic is highly sensitive to packet loss. The loss of fax packets (from latency or jitter for example) causes faxes to fail and be re-transmitted, which uses more bandwidth and lowers the end user's quality of experience. Many carriers desire a FoIP solution that allows them to use their non-T.38 infrastructure to reliably carry fax traffic.

2. T.38 Fax Interoperability: Many enterprises use T.38 for fax transmission. However, variations in the interpretation of the T.38 specification have lead to various interoperability challenges between vendors. There is speculation that improvements or profiles during session setup can alleviate many of these problems.

Goals of the FoIP Initiative

A key goal of the SIP Forum FoIP effort is to bring together researchers, engineers and service providers to exchange ideas, share experiences and propose approaches to address FoIP technology issues and problems. Of course, a key focus is on the use and applicability of SIP to address systemic or architectural problems.

If the initiative identifies concrete proposals to improve FoIP that would require modifications to the underlying protocols, the Forum will forward these proposals to the appropriate groups in the standards bodies, including the IETF, IEEE, or ITU-T.

Some of the topics the Forum's FoIP effort will deal with include:

• Interoperability failures seen in the field or lab
• Reliability or quality issues seen in the field or lab
• Deployment experiences
• Development experiences
• Architectural principles
• Proposals for achieving a higher degree of FoIP interoperability and/or FoIP reliability
• Proposals for soliciting additional real-world feedback from implementers and service providers

Getting the Work Done

To help jump start this work, the SIP Forum hosted a special FoIP Interoperability workshop in San Francisco last November, during the VoiceCon trade show. The event attracted representatives from AEMcom, Audiocodes, Biscom, C4U Solutions, Cisco, Commetrex, Comunycarse, DevFoundry, Dialogic, emFAST, Faxback, NeuStar, Omnitor and Siemens Enterprise, and set forth a plan of action to start tackling the problems with FoIP.

The SIP Forum has established a special Fax over IP Interoperability task group within the main SIP Forum Technical working group where the work will live. The group is currently putting the final touches on a formal "Statement of Problem" document, and has an active mailing list for the participants of the initiative.

For more information about the FoIP Interoperability task group, and about joining in the effort, you can contact Marc Robins, SIP Forum Managing Director, at +1-718-548-7245 or by email at m-director@sipforum.org.

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SIP Forum: Championing Interoperability and moving beyond SIP