(Internet Instant Messaging Protocols (RTP, SIP
The rapid development of the Internet provides day to day new services that were not available previously. The most prominent of these services is instantaneous communication. This refers to the instantaneous communication processes that require the sending and receiving of information at the same time, for example, voice and video conversations in addition to web-based conferences And other applications. The requirements of these applications are the transmission speed between the two parties and to ensure more accuracy in the transmission of audio and video, in addition, to obtain feedback to indicate the quality of service provided, and these requirements show the need for a protocol that manages the process of transmission of information correctly. The Protocol here refers to a set of controls governing a particular task.
We should start with the most popular protocols. It is the most widely used protocol on the Internet. It has a self-relay system in the event of any error in the transmission process. It ensures the transmission of information in a regular sequence and is very suitable for applications Which are affected by the loss of any information such as e-mail and file transfer applications. But these features can be dispensed with in the instantaneous communication, especially if we know that it slows down the connection in addition to that the protocol is concerned with the transfer between party and party only and does not support multicast and does not contain any information about the time of transmission.
A well-known protocol is the UDP protocol, which is characterized by applications that need the fast response with the relative flexibility of error. For example, the human ear can easily adapt to the loss of simple bits of information during voice conversations if this loss is less than ear sensitivity. UDP does not have information about the transmission time. Because these features are not suitable for instantaneous connections, the Real-time Transport Protocol (RTP), which relies on UDP, appears in the transfer process.
The basic functions of the RTP protocol revolve around four functions: 1) Defining the type of packet to be sent; 2) Defining the sender; 3) Setting a numerical sequence known as the packet arrangement for the counterpart; Since RTP uses UDP, there is no guarantee that the information will arrive correctly, and to ensure that the information arrives, another Real-time Time Control Protocol (RTCP) is found in the software layer. It calculates connection statistics such as the number of packets containing errors and the number of Sent packets, the receiver's statistics are sent to the sender and the sender controls the transmission speed.
We now turn to another protocol called the Session Initiation Protocol (SIP), which involves the initiation of direct communication between two or more parties for the transmission of voice and video conversations and conferences via the Internet. The Internet Engineering Task Force (IETF) has adopted this protocol and has been announced through " Request for Comments "(RFC 3261). The way these protocol works is very similar to the HTTP protocol in that it is a text protocol, easy to understand, and flexible to use.
The difference between the RTP and the SIP, since both are protocols for instantaneous communication, may be considered. The difference is shown by the attached graphic. The MOP is responsible for initiating communication between the parties while the information flow protocol Is responsible for transferring information using the UDP protocol.
The increased demand of users for instant messaging applications and the importance of facilitating interconnection and teleconferencing is a great opportunity for short-term applications developers to develop these applications, and competition increases the difficulty of having large applications such as Skype and other applications spread Use.