PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. It combines signaling protocol (SIP) with rich multimedia framework and NAT traversal functionality into high level API that is portable and suitable for almost any type of systems ranging from desktops, embedded systems, to mobile handsets.

Please note that this talk replaces one entitled "10 days, 500k users: how we built a realtime mobile social network in Africa" that was due to have been given by Simon Tennant, who has sent his apologies but is now unable to attend as he has fallen ill. We wish him a speedy recovery.