The application layer uses a protocol for generating, reforming and closing the sessions. This protocol is known as Session Initiation Protocol(SIP). Sip is the major protocol of signaling for Internet applications, thus enabling the execution of features making use of SIP, like video conferencing, Internet gaming, instantaneous messaging, and voice mailing. The reason for this protocol modeling is to study how SIP perform in the setup phase of call and which type of features are supported by this protocol. Media connection is also used by Session Initiation Protocol(SIP). The objective of using SIP protocol is to construct it look alike as we make use of a regular phone,i.e. entering the number where we want to call, listen the ringing of the phone or busy signals.