Jonathan is one of the world's most influential visionaries in how converged communications are transforming our lives. He is co-author of the original SIP specification, the communications protocol at the heart of converged mobile and wireline networks, as well as the recently completed revision of the specification. A leader within the Internet Engineering Task Force (IETF), Jonathan currently chairs the IETF's IP Telephony working group and is former co-chair of the SIP working group. Jonathan is the primary author of a SIP extension known as SIMPLE (SIP for Instant Messaging and Presence Leveraging Extensions) which has emerged as the leading method of standardizing instant messaging and presence among various service providers. He is also co-creator of SigComp, a key SIP compression enhancement that will speed deployment of SIP in mobile networks.

Jonathan has authored more than 20 patents and publications on topics ranging from Internet telephony and SIP to multimedia conferencing and instant messaging. In June 2002, Technology Review, MIT's Magazine of Innovation, recognized Jonathan as one of the world's 100 top young innovators whose innovative work in business and technology has a profound impact on today's world.

In his former position as a key research scientist with Lucent Technologies Bell Labs' High-Speed Networks Research Department, Jonathan led the research and development of Internet telephony services, architectures and protocols. His breadth of experience includes video compression, RTP and media transport, service creation, signaling, service discovery, multicast, QoS and architectures for Internet telephony.

Jonathan earned both bachelor's and master's degrees in electrical engineering from the Massachusetts Institute of Technology. He holds a doctorate in electrical engineering with a focus on IP telephony from Columbia University.