•When a client makes a request for a web page from the server and if the server responds it then it is called that the transaction is complete.
•The request contains the type of the action, the address of the document and version of the HTTP protocol.
•Besides this information the request also sends extra information regarding what software is being used (User-Agent ), what content type (Accept) are understood by the client. This information is called a request header.
•After accepting the request the server processes it and sends information that are represented by the client called response.
•The response contains the status line that contains HTTP protocol used by server, status code and status description.
•Response also followed by a response header which contains the information regarding server software running in server, content type sent, length of the content etc.