Lesson 1

In society, we interact with one another based on a set of common values such as saying hello when greeting each other.
Etiquette is a form of protocol. Networks and the Internet operate on protocols. When two computers communicate there is a shared set of rules that enable them to effectively interact. This module contains information with respect to what a developer should know with regards to Internet protocols
By the end of this module, you will be able to:

1. Describe the nature and purpose of Internet protocols
2. Describe TCP/IP addresses and their classifications
3. Explain the purpose of masks and subnetting
4. Evaluate the protocols used for email
5. Evaluate the protocols used on the Web
6. Describe the Domain Name Service (DNS) and Internet domain names
7. Describe the functions, components, and types of URLs

Protocols define the specific agreed-upon sets of ground rules that make it possible for a communication to take place. Except for special applications, most computers perform their operations such that each hardware or software computer unit will understand what other computer units that they are connected with are saying. Protocols exist for communications between computers, for the communications between various I/O devices and a computer, and for communications between many software programs. A protocol specification defines such communication features as data representation, signaling characteristics, message format, meanings of messages, identification and authentication, and error detection. Protocols in a client-server system assure that requests are understood and fulfilled and that responses are interpreted correctly.

Since the use of a proprietary protocol would be limited to those with permission to use it, protocols are almost always eventually standardized. Although not always the case, protocols that are not standardized tend to die out from lack of use. In fact, international standards are often created to ensure that the protocols are universally compatible. As an example, HTTP, HyperText Transfer Protocol, guides communication between Web servers and Web browsers on the Internet. The movement of data through the Internet is controlled by a suite of protocols called TCP/IP (Transmission Control Protocol/Internet Protocol). Storage devices communicate with a computer using a protocol called SATA. There are thousands of such protocols. New protocols and other standards are proposed and created and standardized as the need arises. XML, RSS, and SIP are all examples of protocols developed recently to meet new demands. Satellite telecasting, near-universal telephone communication, wireless communications, and the Internet all demonstrate powerful and useful technologies made possible by protocols and standards. Indeed, the Internet is a measure of the success to which protocols that govern intercommunication between computer hardware and software have been standardized throughout the world.

The (IP) Internet Protocol is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information.
Historically, IP was the connectionless datagram service in the original Transmission Control Program. The other being the connection-oriented Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referred to as TCP/IP. The first major version of IP, Internet Protocol Version 4 (IPv4), is the dominant protocol of the Internet and its successor is Internet Protocol Version 6 (IPv6).
In the next lesson, you will learn about the purpose of protocols.