SIP Forum: Championing Interoperability and moving beyond SIP Trunking


By Marc Robins
Managing Director, SIP Forum

One of the most common themes -- and challenges -- being discussed in today's IP communications marketplace is without doubt Interoperability. Compared to the old guard (the PSTN and legacy TDM technology), the IP communications industry has at times operated like the Wild West, with vendors creating "envelope-stretching" IP-based products that unfortunately do not play well with others. 

At the Forum, we believe that there is a growing realization within the IP communications industry that achieving interoperability among disparate products and services is key to sustained and long-term growth.

Say what you will about legacy TDM technology, but one great thing about the ole' PSTN was the requirements by regulatory agencies and stringent controls placed by network operators on what went into their networks or attached to them, and the standards that various types of equipment were required to be strictly compliant with.  As a result things just worked.

That monolithic oversight is of course a double-edged sword, as while it ensured interoperability it also limited innovation and provided for a limited set of features and capabilities due to the need to serve the lowest common denominator. 

The SIP Forum was originally founded 8 years ago as a non-profit IP communications industry association to promote the adoption of SIP by the companies developing products and services.  Fast forward to today and now virtually every product is SIP-based.  Since the original "battle" has been won, the SIP Forum is now onto "Job #2" - solving interoperability problems to allow different SIP-based networks and various IP communications products to seamlessly work together. This is a critical need because SIP is a complex standard, and there are a number of different options available to developers of equipment and services, creating a hodge-podge of development choices.

In this regard, the SIP Forum is responsible for producing new industry technical recommendations that provide a specific set of rules, guidelines and best practices that determine which SIP RFC and deployment option to use when and where.  One example is the SIPconnect Technical Recommendation, which provides rules and guidelines for accomplishing SIP trunking, or direct IP peering, between SIP-enabled IP-PBXs and SIP-enabled VoIP service providers.  SIPconnect is a voluntary but peer-reviewed process

The SIPconnect Compliant Program is an associated certification program designed to certify equipment vendors and service providers as SIPconnect compliant and thus offer the highest degree of confidence that they will be able to accomplish trouble-free SIP trunking.

This is one area where the SIP Forum's current industry relevance rings loud and clear. With respect to SIPconnect and our associated compliance program, we have effectively directed vendors and service providers to make important changes to the way they implement SIP so that their offerings strictly adhere to the rules we have established. Without naming names, a number of leading companies have made such changes so that they can be deemed SIPconnect Compliant.

Other notable activities of the Forum include a variety of educational workshops and trade show-related activities that highlight interoperability issues and cover successful applications and deployments, the production of bi-annual SIPit test events, and providing a "meeting place" for developers of commercial SIP-based products and services.

Beyond SIP Trunking

Areas that the Forum is working on other than SIP trunking - areas that cry out for industry consensus and technical interoperability -- are Fax over IP (FoIP), user agents/end-point devices, security and unified communications (OC).

FoIP, for example, is ripe for an industry-approved technical recommendation that spells out the technical method to ensure that Fax works reliably over an IP network.  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 HIPPA (Health-Care related privacy regs and Sarbanes Oxley (public company accounting and reporting regulations), fax is alive and well.

As service provider networks migrate en masse to an IP infrastructure, and enterprises follow suit, fax has suffered. With FoIP, there is an unacceptably high degree of transmission failure (around 2 out of every 10 pages fail to transmit.) What this means is that out of ten 1-page fax transmission, 2 attempts will fail. But 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. To help jump-start this work, the SIP Forum will be hosting a FoIP Interoperability workshop in San Francisco during the upcoming VoiceCon show in November.

In addition, the Forum has restarted our Phone Technology working group (now called the UA Configuration Task Group) to develop an industry-approved SIP end-pointdevice profile that will help ensure consistent, reliable interworking across various vendors systems.

Looking down the road

In the near-term, the Forum will continue to expand our efforts around resolving issues relating to SIP trunking. Longer term, there are obviously other areas where interoperability is a critical issue. The SIP Forum will continue to direct our resources in interoperability testing, profile definition, and work with the IETF and other standards bodies to ensure SIP is the multi-vendor, robust protocol of choice for all IP communications products and services.

Marc Robins currently serves as president of SIP Forum LLC (the operating U.S. subsidiary of the SIP Forum) and as the consulting managing director of the SIP Forum. He is also founder and Chief Technology Evangelism Officer of Robins Consulting Group (RCG), an IP Communications industry consultancy, and partners with leading industry analyst Jon Arnold in the industry information portal IP Communications Insights.