Internet history, Technology and Security (Week 7)

Week 7technology:application Protocols

Welcome to Week 7 of Ihts. This week have less material than and other weeks. I like to think of it as a "seventh inning stretch" – where you get a little breather. This week wraps up the three weeks of "technology" (i.e packets and stuff). After this week we had the weeks on Security and the final exam and then you were done. Thanks for sticking with it. You are almost there.
This week, we'll be covering application protocols. With reliable ' pipes ' available from the Transport layer, we can build applications like Web browsers, file transfer appli cations, or email clients and servers.

Layer 4:applicationsapplication Layer

Now speak application Layer.

The services of the TCP layer is basically to give us a reliable, sequenced end-to-end stream, that can-start in one APPL Ication in one computer and end in an application in a different computer, and has a one-to-do communication.

TCP give us a reliable pipe. When you focus on a certain level, we can ignore other levels of implementation details.

Ports (port):

Extensions like telephone number;
Specific to an application (application).

Two questions about the application layer:

1. which application gets data;
2. What rules and applications to call.
   

One is, which application gets the data. And this was done using a mechanism called ports, and ports allow a IP address, or a single computer, or a single server, T o Serve up multiple services, and then for a client to being able to dial up much like a telephone extension, and pick the SE Rvice that they is interested in.

In a word: The IP address determines which computer you connect to, and the port determines which app will communicate with you after you access the computer.

The various ports are shown:

Common ports

Since TCP provides us with a reliable communication pipeline, what can we do with this pipeline? What problems need to be solved?

So, TCP gives us this reliable connection, we are now can connect to the server, and we desire to connect to by using ports, a nd the question is, what's we going to say across so connection, and what we say across so connection, who talks First, what does the send, what comes back, depends on the kind of server that is talking to.

That is, the World Wide Web server. The client and server in the World Wide Web Use a protocol called HTTP to communicate. The HTTP://dada.dada.dada in URL URLs is.
is the HTTP request/response Cycle. Clicking on a link to a client in your computer, the browser connects to the Web server and sends a request, and Web server sees that it returns the request. The returned document appears on the client's desktop.

Here the teacher showed us a chestnut:

The next teacher will introduce the Telnet client, but it is not considered safe because it is an old and less secure protocols.

Van jacobson-content Centered Networking

Here is about the character introduction, so interested in the message Bar ~

Internet history, Technology and Security (Week 7)