Socket programming assignment
- 1. Socket programming assignment Team Members:-Rajkumar Meena(ug201310025) Ravi Prakash Gupta(ug201310027) The socket programming for communication based on server/client Abstract We are going to introduce the application of the client/server(C/S) mode ,the concept and the programming principle of the socket based on server/client. The transmission layer can provide connection-oriented to use TCP protocol, connectionless-oriented to use UDP protocol. There are two different kinds of services with different kinds of sockets. Only by understanding the characters of TCP protocol and UDP protocol, the service provided by the two protocols for application, can we know what deal with in these protocols, what need to deal with in application, can we easier compile vigorously and healthily, highly efficient client service program. With datagram sockets, communication occurs in the form of discrete messages sent from the sender to receiver; whereas with stream-mode sockets, data is transferred using the concept of a continuous data stream flowing from a source to a destination. Introduction The computer network is the product of the combination between computer technology and communication technology. With the development of the computer network, application of the computer network has been applied to social and economic life in all aspects, for example, Bank teller, point-of-terminal, the verification of check and invoice etc. The design and development of network software is more and more popular, the most of system software (such as operating system UNIX, Linux, Windows versions ,etc) and application software are online versions at present. It is very important to master the network programming principle and method for designing and developing web applications. With the emergence of more powerful desktop computers it became less and less necessary for companies to rely on big, fast mainframe computers in the mid 80's. So, instead of using one big computer with centralized software and 'dumb' terminals on each desk they put a personal computer on each desk and 'empowered' the employee to use whatever software was best for the task at hand. However, companies had large databases which could not be put on every personal computer: first, they were simply too big for typical PC hard disks, and secondly, if one person updated the database, the next person needs to see these changes. Thus, with large databases, they had two choices: stick with the old approach of having one central mainframe computer to handle all database requests, or develop a new strategy. Of course, they chose the second approach and developed the 'client-server' approach. Actually, this approach was not so new: it has been used since the late 60's for the Internet as it existed then. But the need that big
- 2. corporations had for this client-server approach made it quickly very popular (similar to the Internet today: many Universities used the Internet extensively for decades, but the 'general population' did not even know about its existence; as soon as large corporations thought that they could use the Internet for their own purposes, the term became commonplace). Now I am going to introduce server-client approach. Socket- A socket is one end-point of a two-way communication link between two programs running on the network. Socket classes are used to represent the connection between a client program and a server program. The server-An applications runs on a large computer (large meaning either fast or large storage space or both). The server application is usually written in such a way that it does not provide any method to interact with a user. Instead, it waits for other programs to connect (i.e. other programs take the place of a user) and interacts with these programs. Typically, a server application has control over large amounts of data, and can access that data fast and efficiently. It can also handle requests by many clients (more or less) simultaneously. The client-An application that runs on a personal computer. It has an extensive and appealing user interface, but it has no data that it can manipulate or present to the user. The client application 'asks' what a user wants, then connects to the server application to obtain that data. Once the data has been obtained, it is presented to the user in a nice format. A client usually gets the data from one server at a time, and interacts with one user only. Client-Server programs can run on any type of network. These days, however, people are most interested in them when they utilize the Internet. So, we will only talk about client-server programs running on the Internet, and we will oversimplify many issues to understand the basic ideas and concepts. The Principle of Socket Communication Socket is a kind of abstract data structure provided by operating system, it is used to build an access in the absence of correlation between the process of sending to receive messages. Socket has been providing communications endpoint process in fact and has been accomplishing the data transmission through the endpoint. First, the socket function call attendant to create a type of Socket, then bind socket into client-side through bind function. Attendant set listening attentively to the formation the length through transferring the listen function to make a prepare from client client's requests. Attendant transfers the accept function to start in the port which binding to listen attentively comes from the connection request which the client carries. Client-side build a type of socket through socket function(it should be similar with the type of client- side’s socket). Then connect function call to the attendant where the host issued a connection request. It need to designate service where the host IP address and socket, as well as other relevant information when you link it . TCP is a connection-oriented protocol that provides a reliable fl ow of data between two computers. Example applications that use such services are HTTP, FTP, and Telnet. UDP is a protocol that sends
- 3. independent packets of data, called datagrams , from one computer to another with no guarantees about arrival and sequencing. Example applications that use such services include Clock server and Ping. The TCP and UDP protocols use ports to map incoming data to a particular process running on a computer. Port is represented by a positive (16-bit) integer value. Some ports have been reserved to support common/well known services: ftp 21/tcp telnet 23/tcp smtp 25/tcp login 513/tcp http 80/tcp,udp https 443/tcp,udp User-level process/services generally use port number value >= 1024.