SIP is a lightweight, transport-independent, text-based protocol. SIP has the following features: Lightweight, in that SIP has only four methods, reducing complexity Transport-independent, because SIP can be used with UDP, TCP, ATM & so on. Text-based, allowing for low overhead SIP is primarily used for VOIP calls | Session Initiation Protocol (SIP) Features of SIP SIP is a lightweight, transport-independent, text-based protocol. SIP has the following features: Lightweight, in that SIP has only four methods, reducing complexity Transport-independent, because SIP can be used with UDP, TCP, ATM & so on. Text-based, allowing for low overhead SIP is primarily used for VOIP calls Functions of SIP Location of an end point Signal of a desire to communicate Negotiation of session parameters to establish the session And teardown of the session once established. How SIP works SIP user agents: like cell phones, PCs etc. They initiate message writing. SIP Registrar servers: They are databases containing User Agent locations; they send agents IP address information to SIP proxy servers. SIP Proxy servers: accepts session request made by UA and queries SIP registrar server to find recipient UA address. SIP Redirect servers: they help communicating outside the domain Continued Continued Our user A tries to | Session Initiation Protocol (SIP) Features of SIP SIP is a lightweight, transport-independent, text-based protocol. SIP has the following features: Lightweight, in that SIP has only four methods, reducing complexity Transport-independent, because SIP can be used with UDP, TCP, ATM & so on. Text-based, allowing for low overhead SIP is primarily used for VOIP calls Functions of SIP Location of an end point Signal of a desire to communicate Negotiation of session parameters to establish the session And teardown of the session once established. How SIP works SIP user agents: like cell phones, PCs etc. They initiate message writing. SIP Registrar servers: They are databases containing User Agent locations; they send agents IP address information to SIP proxy servers. SIP Proxy servers: accepts session request made by UA and queries SIP registrar server to find recipient UA address. SIP Redirect servers: they help communicating outside the domain Continued Continued Our user A tries to call user B (1) Domain SIP proxy server now queries Registrar server in the same domain to know about user B’s address (2) Registrar responds with the address (3) SIP proxy server calls B (4) User B responds to SIP proxy (5) SIP proxy answers to User A (6) Now multimedia session is established on RTP protocol (7) More about SIP SIP relies on SDP and RTP protocols SIP proxy is a server in a SIP-based IP telephony environment The SIP proxy takes over call control from the terminals and serves as a central repository for address translation (name to IP address) SIP Advantages SIP is a based on HTTP and MIME, which makes it suitable for integrated voice-data applications SIP is designed for real time transmission SIP Advantages Uses fewer resources Is Less complex than protocol SIP uses URLs and is human readable SIP Disadvantages First one: One SIP challenge is that SIP message contain information that Client and/or server will like to keep private but SIP header as well as .
