SIP Entities
S I P: A C L O S E R L O O K
User Agent (SIP “endpoints)
- UA Client: intiates requests
- UA Server: responds to requests
- Resides in: softswitches, gateways, handheld
- and wireless devices, DSL/cable equipment
Proxy Server
- Routes messages and hosts service logic
Redirect Server
- Returns routing information tot he initiating endpoint
Registrar
- Records SIP URL and associated IP address for
- subscriber mobility