Basic functionality Addressing A SIP URI has the form of sip:username@host ■Registration allows one or more IP addresses to be associated with a particular SIP URI Session control invite another user agent to a particular session,to modify an ongoing session,and to terminate a session
Basic functionality ◼ Addressing A SIP URI has the form of sip:username@host ◼ Registration allows one or more IP addresses to be associated with a particular SIP URI ◼ Session control invite another user agent to a particular session, to modify an ongoing session, and to terminate a session
Architecture Location Server SIP SIP Redirect Registrar SIP Server SIP SIP SIP SIP SIP User SIP Proxy SIP User Agent Server Agent RTP-Based Media
Architecture
SIP user agent initiates SIP requests SIP proxy server a signaling router for SIP messages receives a SIP message from a SIP user agent or another proxy and routes it toward its destination security or authentication
◼ SIP user agent initiates SIP requests ◼ SIP proxy server a signaling router for SIP messages receives a SIP message from a SIP user agent or another proxy and routes it toward its destination security or authentication
SIP registrar accepts SIP user registrations allows one or more IP addresses to be associated with a particular SIP URI ■SIP redirect server redirect a SIP client session to a new SIP URI Location server maintains the location database for registered SIP user agents
◼ SIP registrar accepts SIP user registrations allows one or more IP addresses to be associated with a particular SIP URI ◼ SIP redirect server redirect a SIP client session to a new SIP URI ◼ Location server maintains the location database for registered SIP user agents
SIP Methods ■REGISTER For registering contact information ■INVITE,ACK,CANCEL For session establishment ■BYE For session termination OPTIONS For determining the capabilities of a SIP UA
SIP Methods ◼ REGISTER For registering contact information ◼ INVITE,ACK,CANCEL For session establishment ◼ BYE For session termination ◼ OPTIONS For determining the capabilities of a SIP UA