The Internet is a network of networks. It links billions of devices together all around the world. It is a global system which is designed to move information.
The Internet is becoming the town square for the global village of tomorrow.
The purpose of this article is to provide a basic understanding of the internet and its working. To understand the Internet better, in this series we will explore its history and dive deep into its design and architecture.
When computers first arrived in the 1960's, wired and dedicated connections were used to exchange data between them. This type of communications was limited to short distances only because of signal loss and infrastructure limitations. Back in the days' many organizations were working to develop the required technology for effective communication between computers.
The packet switching concept was invented by Paul Baran in the early 1960's and is used in ARPANET, the world's first packet switching network.
TCP/IP, the protocol used in early packet switching networks like ARPANET and the Internet itself was introduced by Vint Cerf and Bob Kahn in 1974 in IEEE paper titled A Protocol for Packet Network Intercommunication .
We will discuss core concepts and design philosophy that helped internet not only survive the boom but also to flourish and scale accordingly as millions of new users join it daily.
When you send a mail using postal service, you write down your own address and the destination address on the envelope and put it in a mailbox. The postal service then takes your mail and deliver it to the destination. Postal service encapsulates all the underlying technology and infrastructure it uses to deliver your mail to the destination. Thus providing you with a hassle-free service.
The same way, on the Internet, each device have a unique address which is required for any type of communication over it. These addresses are called IP address. When you send data over the internet, the messages are first divided into manageable chunks called packets. To each packet, source and destination addresses are added. An offset is also added to packets for reassembly at the destination in correct order.
The packets move through the network, guided by the routers towards there destination. Routers are computing devices that specialize in moving packets across the network. The protocol responsible for moving packets from source to destination is Internet Protocol. We will discuss routers and routing in detail in this series.
Packets can follow different paths and arrive at the destination out of order. It is the responsibility of TCP - Transmission Control Protocol to put packets in correct order and check if all packets arrive correctly at the destination computer. If a packet is lost in transmission, TCP requests the source computer to send it again. Once all packets are accounted for, TCP assembles them back to form the original message and transmission is complete.
There are more to that, which we will cover in the next few articles.