Jeremy George <jeremy.george@yale.edu> (November 25, 2003) I - Architecture SER (SIP Express Router) is an open-source SIP proxy, redirect and registrar server from Iptel.org, an offshoot of the German national research company FhG Fokus. In addition to voice call signalling, SER includes support for SMS, presence, SIP-based instant messaging and a jabber gateway among other applications. The desi