Connection to the X-Stream - Case Study Example

Networking Principles Introduction Every computer accessing X-stream must have a unique address. Computers connecting to X-Stream via an Internet Service provider will have short-lived IP addresses assigned to them for the period of the dial-in session. Otherwise computers connecting from local area network are likely to have permanent IP addresses or be issued with a temporary address from Dynamic Host Configuration Protocol. All in all, any computer connected to the X-Stream will have an individualized IP address. Connection to the X-Stream might involve conversion of alphabetic texts to electric signals and vice versa. One of accomplishing this would be through the protocol stack. The protocol stack adopted by the internet is the TCP/IP protocol stack based on the two main communication protocols employed. The request to access X-stream would begin as a message at the top of the protocol stack in the client’s machine. In case the involved message is long, every stack layer that the message goes through might have the message broken down into smaller data chunks. This would be based on the reason that data sent through computer networks have got to be in manageable chunks called packets. The sent packets will go via the Application Layer then proceed to the TCP layer. Every packet will have a port number assigned to it. This would happen because a number of programs could be sending messages to the server at X-stream or making use of TCP/IP stack. There is need to know the program on the server to receive the message since it will be listening through a particular port. After the packets have gone through the TCP layer, they proceed to the IP layer. It is at this level that every packet will receive a destination address associated with it. Every message packets having an IP address and a port number assigned to it shows readiness for transmission over the internet. Transformation of the alphabetic text harbored in the message packets into electronic signals will be left to the hardware layer. This is followed by transmission. Finally, the packets reach the destination server. At this stage, the packets begin at the bottom of the destination server’s TCP/IP stack working upwards. While the packets move upward via the stack, every routing data which the sending computer’s stack adds like port number and IP address will be stripped from the packets. While data reaches the stack’s top, the packets shall have been re-assembled to the original form. After packets have passed through the local equipment of the ISP and the phone network, they will be rerouted onto the backbone of the ISP. From this point, the packets will often trail along a number of dedicated lines, routers or backbones and other networks till such a moment when they get to the destination. In this context, this will be the web address x-stream.leedsmet.ac.uk. The client computer will not know the location of the server and packets will not be sent just to any computer. The routing tables kept by routers that are connected to the internet bear the information that is required to get packets to their respective destinations. Upon the arrival of a packet at a router, the router will examine the IP address that was put by the IP Protocol layer of the client’s machine. The router will then examine its routing table. In case the network that contains the IP address is found, packets get sent to that given network. In case the network with the state IP address is not found, then the packet will be sent on a default route by the router and this often to the next router. In case the next router does not know where to send the packet, the packet will continuously be rerouted upwards till such a moment when it gets to the NSP backbone. In accessing the X-stream, the IP address of the hosting server is probably not known. One way of letting the web browser to know about the whereabouts of the server is through the Domain Name Service (DNS). The destination server is believed to host DNS servers though the DNS server cannot contain a whole database. In case a given DNS server at x-stream.leedsmet.ac.uk does not constitute does not contain the domain name that a client computer did request for, the DNS server will redirect the requesting client computer to some other DNS server. Domain Name Service bears a hierarchical structure similar to that of IP routing. The computer that requests for a name resolution for x-stream.leedsmet.ac.uk is to be re-directed up the hierarchy till such a moment when a DNS server to resolve the domain name in the request is found. Upon set up of an internet connection, a single primary DNS server together with one or multiple secondary DNS servers will be stated as part of the performed installation. In this manner, any internet applications like access to X-stream will be able to perform in an appropriate way. For instance while a visitor at a client’s browser types the address x-stream.leedsmet.ac.uk, the browser first tries connecting to the primary DNS server. Immediately after the browser has obtained IP address associated with the domain name that was provided in the address bar of the browser, the browser tries connecting to the target server requesting for the page that the site visitor was in need of. Under the application layer of the protocol stack is the TCP layer. In a request for x-stream.leedsmet.ac.uk opens a connection to the server, the message that the request sends will be passed down the stack up to the TCP layer. TCP has the duty to have application protocols routed to appropriate applications on the destination server. To achieve this, port numbers prove useful. Ports can be deemed as separate channels on every computer. The manner of operation of TCP will be such that:- In case the TCP layer receives data from the application layer protocol placed above it, it tries segmenting the same into some manageable chunks followed by addition of TCP header with particular TCP information for eating the chunk. The information that the TCP header will bear will be inclusive of the port number of the application to which the data in question needs to be sent. Upon reception of a packet from the IP layer that is placed below it, TCP layer will attempt stripping the TCP header from the packet, do some reconstruction in case of need then finally send the data to the appropriate application through the use of the port number that is obtained from the TCP header. Considering that TCP is connection oriented the application centered on a client browser requesting an X-stream web page have to establish some connection prior to exchange of data. Use of TCP in this context would be considered as reliable for the reason that every successful reception of a packet is followed by an acknowledgement being sent to a sender just to confirm delivery. Besides, TCP will include a checksum in the header to check the received data against errors. The client application aimed at accessing x-stream.leedsmet.ac.uk will generate a transitory port number for all TCP connection it establishes. The HTTP request connection used in this context will be distinctly specified by the 5 parameters- server IP address, transitory port number, client IP address, TCP and 80. The difference in ephemeral port numbers witnessed among applications allows the server to distinguish between different applications. Retrieval of documents off the web server will entail formation of TCP connection which basically involves a client sending an HTTP request followed by response by the server towards the same. The measurement tool could adopt Telnet in accessing the web server. One option that could be explored while sending the request message to load the x-stream.leedsmet.ac.uk page would be an attempt to Telnet to port 80 following the establishment of a TCP connection. In this request message revolving around access to x-stream, a client has to specify the protocol version used by the browser in question-such as HTTP/1.0. In the response message, the server will send information regarding the content type of the document such as image/jpg or text/html. A client sends request to a web server for a web page. Connection between the server and the client gets disconnected after the server services the client’s request. There is need to make a new connection for every request These are the occurrences in case a visitor types a URL in the web browser:- 1. In case the typed URL constitutes a domain name, the browser will connect to some domain name server with the intention of retrieving the web servers corresponding IP address. 2. The browser gets a connection to the web server then uses the protocol stacking in sending an HTTP request to the web server. 3. The server receives the request then checks for the requested page. The server sends the page if it is found or an error message in case the requested page is non-existent. 4. The browser will then receive the requested page back after which the connection is closed. 5. The browser then parses the page looking for other elements of the page such as images that it needs to have the page completed. 6. For every element required, the browser will make more and more connections along with HTTP requests to the server for every element. 7. If the browser is done with loading all the page elements associated with X-stream the entire page will be entirely loaded within the browser window. 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