# The Computer Revolution/Internet/Protocols
## TCP/IP

TCP/IP(Transmission Control Protocol/Internet Protocol) is built into the UNIX operating system. It is used by the Internet, making it the de facto standard for transmitting data over networks.

### TCP

TCP - ensures the verification of the correct delivery of data from client to server. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.
TCP is typically used by application software that require guaranteed delivery. It is a sliding window protocol that provides handling for both timeouts and retransmissions.
TCP creates a complete duplex virtual connection between 2 endpoints. Each endpoint is defined by an IP address and a TCP port number and is implemented as a finite state machine.
The byte stream is transferred in segments. The window size determines the number of bytes of data that can be sent before an verification from the receiver is necessary.

### IP

IP - is responsible for transferring packet of data from one node to another. IP forwards each packet based on a four byte destination address (the IP number). The Internet authorities assign ranges of numbers to different organizations. The organizations assign groups of their numbers to departments. IP operates on gateway machines that move data from department to organization to region and then around the world.

## HTTP

HTTP stands for HyperText Transfer Protocol. Tim Berners-Lee developed the web protocol to act as web addresses. By using the protocol, you can connect to web servers without the server knowing who you are. The request to the site does not reveal if you have visited the site previously. Therefore, the protocol is basically stateless, unlike FTP, which is interactive.
The only documentation for early versions of the HTTP/1.0 protocol consisted of a discussion draft in HTML form. This documentation is available for historical reasons only, since it has been replaced by the Internet Drafts, Informational RFC, and now Standard track documents, and does not reflect current practice among WWW applications. The purpose for the protocol is so you can retrieve information, promptly and with minimal hassle.
Connection is the establishment of a connection by the client to the server. Request is the act of sending a request message, by the client, to the server. Response is the sending, by the server, of a response to the client. Finally, the closing of the connection by either both parties.

## FTP

What is FTP:
FTP stands for "file transfer protocol." FTP is the Internet's tool for transmitting files between certain computers. Basically it is a way of sending and receiving files over the internet. FTP enables you to gain access to files that are stored on a hard drive on someone else's computer which is connected to the internet.
FTP is just one of many ways to share information and data over the internet. With FTP the main objective is to have individual/direct control over a certain file. You are able to find out where the file comes from and where the file must go. The easiest way to use FTP is to use a program that is specifically designed to use the File Transfer Protocol.
The 2 different types of files are text and binary, as you could have guessed there is and FTP method for each of these files. The text files consists of letters and numbers that make up text, where as the Binary files are those that are comprised of sounds pics, and programs. You can only transfer these files if they are in the proper format or they will not work.

## TOP LEVEL DOMAIN

The top level domain is the part of the URL that specifies what site is part of government, business, education and so on. It's also easy to remember since it's always after the "dot" in the Web address, for example .com, .edu, .info and so on. There is 3 types of top-level domains those are:
- Country code top-level domains : Used by a country. It is two letters long, for example "ca" for Canada.
- Generic top-level domain : Used for commercial organizations. It is three or more letters long. for example .aero, .coop and .museum, and unsponsored top-level domains such as .biz and .info
- Infrastructure top-level domain: The top-level domain ARPA is the only confirmed one. Root has been known to exist without reason
Registration
Internet domain names are registered with any of several registrars. To find out if a domain name is taken, one popular domain name registrar is Go Daddy (www.godaddy.com).

## URL

What is URL?
Uniform Resource Locator (URL) is a reference to a resource on the internet (an address). The URL has 4 components:
* Web Protocol
* Domain Name (web server name)
* Directory name or path
* File
The web protocol (http://) is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. This web protocol was developed by Tim Berners-Lee and is seen at the beginning of web addresses.
The domain is a location on the internet (often referred to as web addresses). Domain names are hostnames that provide more easily memorable names to stand in for numeric IP addresses. They allow for any service to move to a different location in the topology of the Internet (or another internet), which would then have a different IP address.
A directory name is the name on the server for the directory, or folder from which your browser needs to pull the file
A file name is a special kind of string used to uniquely identify a file stored on the file system of a computer.The file is the particular page or document that you are seeking.

## STANDARDS

In order to ensure that products that are developed can work with other products, a series of networking standards have been developed to address how the device connects to the network as well as how the devices communicate. The most widely used standard with wired networks is the Ethernet. Some of the wireless standards that currently exist, classified by their range are: short range connecting network elements within a small perimeter (Bluetooth, wireless USB, UWB, WiHD, ZigBee), medium range connecting computers to LAN (Wi-Fi) and long range developed to provide internet access to a large area for fixed and mobile users(WiMax, Cellular standards).