WAP Gateway - Web server

WAP Gateway - Web server

Now we can establish a connection to the WAP gateway from the WAP device, but the gateway also
have to talk to the origin web server for us to get the information we want. This communication is
done as in the ordinary World Wide Web (WWW) model. Version 1.1 of HTTP can handle multiple
requests in one and the same session that is an improvement from version 1.0 where only one
transaction can be executed per session. For example, a HTML page with <img>-tags must establish
a new connection for every image the browser want to retrieve, in HTTP/1.0.
Here is an example of a communication in HTTP/1.0.
1. The gateway sends a connection request to the http port (i.e. 80) on the server.
2. The server responds to the connect request with a connect response.
3. The gateway acknowledges this response and sends the first bytes of the real request.
4. The server acknowledges the first part of the request, but doesn't send any data yet.
5. The gateway can send the a couple of more request before receiving a response from the
server, so it sends two more request and is done, now the gateway just have to wait.
6. The server acknowledges the second and third request and sends the first real data that has
been requested.
7. For every data the gateway receives it sends an acknowledgement or it can wait for a couple
of packets and acknowledge them all in one message.
8. The server sends the rest of the data in as many packets that is needed and the final packet
contains a flag indicating that the connection is being closed.
9. The gateway acknowledges the data and sends a message announcing that it too is closing
the connection.
10. The server acknowledges the close.
Step 1-3 is called a three-way handshake. The gateway sends a connection request, the server
responds and finally the client acknowledges the response. In HTTP/1.0 this connection establishment
and the disconnection (step 9-10) have to be done for every transaction and this cost extra time.