P. Vicman, S. Nedok, B. Vlaovi?, and Z. Brezo?nik
In this paper SIP Info Service (SIPIS) is presented. The
main purpose of this system is to deliver prerecorded
audio data (traffic news, weather reports, etc.) over the
Internet to the receiver using RTP (Real-time Transfer
Protocol) with the UDP/IP (User Datagram
Protocol/Internet Protocol) as its transport protocol.
For signaling purposes SIP (Session Initiation
Protocol) and SDP (Session Description Protocol) are
used. The system can be called by any SIP user agent.
The main stress in the development of this system was
on SIP and SDP. SIPIS consists of UDP server, SIP
and SDP parser and user agent for call control. UDP
server and client are used for transmission of UDP
packets carrying SIP and SDP messages. Parsers
dismember corresponding messages and SIPIS user
agent's job is to receive requests for audio information
and then play it to the calling user.