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What Is the Internet?
A worldwide network of networks: ISPs, IP addresses, routers, packets and the cables under the sea.
A Network of Networks
A network is two or more computers connected to share data. The tea room's router, laptop and card machine form a small network. The internet joins millions of networks like this — homes, schools, companies, universities and data centres — into one giant network.
How You Connect
- An Internet Service Provider (ISP) sells you a connection. In Sri Lanka, companies such as SLT-Mobitel and Dialog provide fibre, ADSL, 4G and 5G connections.
- A router connects your home or office network to the ISP's network, and decides where each piece of data should go next.
- Your ISP connects to bigger networks, which connect to each other at internet exchange points, and to other countries through undersea fibre-optic cables.
Packets and IP Addresses
Data is not sent in one big piece. It is split into packets. Each packet can take a different route; routers pass them along, hop by hop. At the destination, the packets are put back in order. If one is lost, it is sent again. The rules that make this work are called TCP/IP — a protocol (an agreed set of rules for communication).
Packets can take different routes
Practice
Choose all that apply.
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