The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to communicate with each other. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. The Internet carries an extensive range of information resources and services, such as the web pages that make up the World Wide Web (WWW) and the infrastructure to support email and streaming services.
Hardware Required to Connect to the Internet
Modem - Modulator/Demodulator
Many computers still connect to the internet using the analogue telephone system (POTS – Plain Old Telephone System). Of course, computers can only process digital information (1s and 0s) so any incoming analogue information must be converted to a digital signal before it can be processed and vice versa. A modem does exactly this job. Originally, modems could only transmit data at fairly low rates (up to 300 bits per second), but at their best they could sometimes manage 56 kbps (kilobits per second). This is still incredibly slow when compared to today’s standards (220 MB)!
ADSL – Asymmetric Digital Subscriber Line
Most users download significantly more data than they upload. ADSL provides faster broadband speeds along analogue telephone lines by utilising bandwidth that is not used by a voice telephone call. The bandwidth (and bit rate) is greater toward the customer (downstream) than the reverse (upstream). This is why it is called asymmetric. Obviously, this is not great if you need to upload loads of data!
Originally designed to carry radio frequency TV channels, they are now commonly used to deliver broadband internet access as well. Many cable modems attached to a single cable can use the same frequency band, allowing them to share the same channel. Usually, ‘up’ and ‘down’ signals are kept separate. Many broadband modems include the functions of a router with Ethernet and WiFi ports.
A router is a device that forwards data packets between computer networks. When the router receives a data packet it reads the address information in the packet to determine its ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. This continues until the data packet reaches its final destination.
Information contained within a routing table will include:
Which connections lead to particular groups of addresses
Priorities for connections
Rules for handling traffic
The router must ensure that:
Information is only sent to the addressee (prevents data from clogging connections)
Data reaches the intended destination
Routers are useful for joining two networks and they can sometimes translate different protocols used by them.
The internet relies upon routers to ensure that data packets get delivered by the most efficient routes available at any given time.
Broadband routers make use of Ethernet standards in a home network. They often include Wi-Fi access which reduces the need for cable connections.
Watch Warriors of the Web Video to help you understand how traffic moves around the internet and the role of the router or switch.