Posted: 02-July-2008 07:37:40 AM By: sagitraz
SIP Architecture:
SIP Architecture basically includes:
UAC (user agent client)
Caller application that initiates and sends SIP requests.
UAS (user agent server)
Receives and responds to SIP requests on behalf of clients; accepts, redirects or refuses calls.
SIP Terminal
Supports real-time, 2-way communication with another SIP entity. Supports both signalling and media, similar to H.323 terminal. Contains UAC.
Proxy
Contacts one or more clients or next-hop servers and passes the call requests further. Contains UAC and UAS.
Redirect Server
Accepts SIP requests, maps the address into zero or more new addresses and returns those addresses to the client. Does not initiate SIP requests or accept calls.
Location Server
Provides information about a caller's possible locations to redirect and proxy servers. May be co-located with a SIP server.
Multimedia conferencing Architecture:
Multimedia conferences require real-time delivery of at least the audio and video information streams used in the conference. In an ISDN context, fixed rate circuits are allocated for this purpose --whether their bandwidth is required at any particular instance or not. On the other hand, the traditional Internet service model (``best effort'') cannot make the necessary quality of service available in congested networks. New service models are being defined in the Internet together with protocols to reserve capacity or prioritize traffic in a more flexible way than that available with
circuit switching
Posted: 03-July-2008 01:01:37 PM By: kenhaulotte