Real-world SIP Interoperability: Still an Elusive Quest Archana Rao and Henning Schulzrinne Department of Computer Science Columbia University http://www.cs.columbia.edu/IRT/voip-testbed/ December 3, 2007 1 / 4

Systematic Study of Interoperability A Framework for Identification and Analysis Define a minimum set of call flows constituting basic interoperability RFC 3665, RFC 3666, RFC 4317 Use a VoIP testbed to realize a variety of real-world SIP infrastructure setups Columbia VoIP testbed Study the behavior of SIP end-clients and servers in each of these scenarios Interoperability matrices Categorization of common issues  Lack of clarity in the specification Implementation of an older specification Incomplete implementation of the specification Incorrect implementation of the specification Failure against robustness tests

your equipment here :-) http://www.cs.columbia.edu/IRT/voip-testbed/ http://www.cs.columbia.edu/IRT/voip-testbed/ your equipment here :-)

Real-world SIP Interoperability Summary Tests indicate that basic-level interoperability is far from perfect Instances of interoperability failures illustrated in our workshop paper Achieving Interoperability shouldn’t be left to vendor non-interoperability damages SIP brand, causes grief for third parties and harms customers Going Ahead Establish designated interop liaison for each vendor calling customer support unlikely to be useful Encourage vendors to publish interoperability reports in standard format Provide self-certification tests, supported by a remotely accessible test rig