Defining TCP/IP protocols
Q
If you are writing for beginners, it would be helpful if you could explain abbreviated terms such as "TCP/IP protocols".
A
What in the world is TCP/IP.
Yikes!
A question with an incredibly long answer.
But I will do my best...
In a network made up of hundreds of types of hardware, manufactured by hundreds of proprietary vendors, thousands of software packages, from thousands of software shops, and millions of human users speaking all sorts of languages, you can imagine that communication is a pretty tough task.
How could all these network nodes (hardware, software and people) talk to each other?
Well, the way this type of problem is solved in information technology is through the use of protocols, or standards.
Protocols define a standard way of communicating.
By using protocols, everyone agrees to certain communication guidelines.
And so long as everyone follows those guidelines, they are assured that they can be understood by any other member of the community.
TCP/IP (The Transmission Control Protocol/Internet Protocol) is the suite of protocols that "drives the Internet".
Specifically, TCP/IP handles network communications between network nodes (computers, or nodes, connected to the net).
The suite is actually composed of several protocols including IP which handles the movement of data between host computers, TCP which manages the movement of data between applications, UDP which also manages the movement of data between applications but is less complex and reliable than TCP, and ICMP which transmits error messages and network traffic statistics.
Internet Protocol (IP) is a connectionless protocol that gateways use to identify networks and paths to networks and hosts.
In other words, IP handles the routing of data between networks and nodes on those networks.
You will be familiar with IP because in order to address web pages, you must use domain names like www.barclayscapital.com, or their numerical counterparts called IP addresses.
NOTE:
Domain names are far easier to remember than IP addresses so we usually use domain names instead of IP addresses and rely upon Domain Name Servers to tie domain names to their IP address counterparts behind the scenes.
IP addresses are unique sets of four period delimited octets that represent individual hosts on specific networks.
A TCP/IP octet is a number between 0 and 255. Thus, an IP Address might look something like:
30.85.1.26
which you might read as something like "computer named 26, on network 1, on host 85, of network 30."
NOTE:
255 is usually a reserved number which means broadcast to all hosts and 0 represents "this", or the current host.
Besides defining the address scheme, IP also handles the transmission of data from an originating computer to the computer specified by the IP address.
It does so by breaking up large, unwieldly chunks of data into easily manageable IP packets that it can deliver across the network.
That is why we talk of IP being a connectionless protocol.
In an effort to better manage network traffic, IP specifies the protocol for breaking single messages into a slew of portions.
Each portion is responsible for finding its way across the network based on changing traffic congestion and the IP protocol.
Each time a message arrives at an IP router, the router decides where to send it next.
There is no concept of a session with a preselected path for all traffic.
Routers can send data along the path of least resistance regardless of local network traffic congestion.
If one phone line on the network breaks down, for example, traffic can still reach its destination through a roundabout path.
Whereas IP focuses on getting data across the vast network from one computer to another, TCP assures that the data gets sucked off the network connected computer and delivered to the receiving application and that the data is delivered in the correct sequence.
Recall that since IP chops messages up into packets, we need to assure that the messages are assembled correctly at the other end of transport.
And if any errors occur during transport, such as message degradation or the loss of some packets, the sender will know to resend.
TCP also tries to optimize network bandwidth by controlling the flow of information dynamically, slowing down as network traffic becomes congested.
So, in summary, the TCP/IP protocol is a communications protocol which assures that data sent from one place on the net will be received AND understood at the other end.
Selena Sol contributes to the JavaBoutique's Introduction to Java. Selena curently works for Barclays Capital in London, one of the leading global investment banks in Europe and has worked as a software developer for the National Center for Human Genome research, Microline Software, Neuron Data, and Electric Eye in Singapore. Selena is perhaps best-known for creating the Public Domain Web Script Archive (Extropia) and writing several books on Web Programming (Perl, CGI, Java).
Email: selena@extropia.com
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