IP address and TCP Port Framework EXAM HELP?

Question

Q. On protocol layering. One of the typical examples of protocol layering in internet is the stack of HTT, TCP, IP.

When a TCP connection is established, its client is identified by a pair (IP address, TCP port), similarly for its server side.
Illustrate briefly how this framework enables the sharing of a resource in networked applications, taking a web server as an example.

I think i have MISUNDERSTOOD the question.. My answer is:



Port is uniquely differs applications or processed running off a single computer and enables them to share a single physical connection to a packet switched network.

port number is added to IP address. this completes the address for communication session.

Packets are routed across the network to a specific destination IP address and then upon reaching the destination computer, then further routed to specific process.

web server delivers web pages. every server has an IP address and domain name.

enter URL in browser.. e.g www.page.com/index.html this sends a request to the web server whose domain name is page.com. The server then fetches the page names index.html and sends it to the computer at address ***.***.****.***. Then to the application (browser) by using port number.



I have a feeling my answer is incorrect....

Answer 1

There is no such thing as a HTT protocol stack... (and I notice typos in your other question which is why I didn't answer it)...



I can see how you misunderstood the question....

But its just underlining the fact of Protocol stacks...

HTTP, TCP and IP...



These are called protocol stacks because many other protocols are used in them.



They gave an example of the TCP above how it uses two in its stack of IP address and Port...



Now the question wants you to give an example of the HTTP Stack (webserver).



First you start at the application layer...



Browser *WWW Contacts a Server via its network name which *DNS transfers into *IP Address... with *port number of 80 which opens up a Session in the Server Application being a WebServer

Answer 2

The IP address identifies a specific computer, but does not identify anything specific within the computer. The port number identifies the specific program end point of a connection to the computer.



When a computer's browser attempts to access a web page using the HTTP protocol, the requesting computer picks an arbitrary unused port (in the range 1024 to 65535) as the port from which the request will be sent. The browser will be attached to this port. The HTTP request will be directed to port 80 at the website. Port 80 is the port nominated for receiving HTTP requests, and the web server's server process will be attached to port 80 so that it can receive and process the request.



The server process will generate the response (the web page that has been requested), and send this back to the IP address and port number that requested it. When the response reaches the requesting computer, the browser is already listening on the correct port (the port that sent the request) for the web page to arrive.



If a second browser window or tab is also in use, it will be allocated a different port from which to send its requests. This way, each browser window or tab works independently of the other windows. Each browser window will still send HTTP requests to port 80 at the web server. Other protocol servers use other port numbers. For example, HTTPS servers attach to port 443. FTP servers attach to port 21. Telnet to port 23. There are many other ports reserved for specific services.



I hope this helps you in understanding the operation of ports within TCP.

Answer 3

I wouldn't say that your answer is incorrect, you're just being a bit vague.



I think you should just focus on the main things the question asks and describe them a bit:



IP addressing: Gives you a unique identifier in the internet which allows messages to be directed to you. In a web server, the IP address is replaced by a domain name which your computer uses to query a DNS server to find the IP address of your web server. This is because words are easier to remember than a series of numbers.



TCP: Uses a particular structure of transferring data known as a "packet". Each packet contains a header in which - among other things - the recipient's IP address is stored. This allows the packet of data to be directed successfully to its destination over the Internet through a series of routers.

(Perhaps mention its "failsafe" method of re-sending packets if no response is received after so much time)



HTT: The protocol controlling the transfer of HyperText files (web pages). It ensures that the recipient receives the file all in one piece so that the webpage is displayed fully and correctly.



Then mention how all these must work to request and send a resource from one computer to another:

TCP uses IP to direct data packets. HTT uses TCP to send the file to the client.

The client requests the file from the server using TCP.