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Chapter 2. Edubuntu Workstation |
There are two components of a network: hardware and software. This section will give an introduction to both.
Networking works by breaking files and other data into little packets of information. These packets are transfered over a network. The difference between various types of networks is how they transfer packets.
There are two types of networking hardware: wired and wireless.
An important fact to remember is that a network will be only as fast as the slowest part. So, if you have a faster wired network but a slower wireless network, the speed to the wireless clients will be restricted by the speed of the wireless network.
Wired networking transfers packets over a cable that resembles a telephone cord, but with more wires. Wired networks can transfer packets at one of three possible speeds: 10 Mbit/sec, 100 Mbit/sec, or (Gigabit) 1000 Mbit/sec.
A network is only useful if it can connect multiple computers. There are some pieces of hardware that allow multiple computers to be connected in a network. They look alike, but they function differently and, likewise, operate at different speeds.
A hub is the simplest way to connect multiple computers. A hub has a lot of ports in the front and usually has several small lights corresponding to each port. The hub takes a message it receives on one port and resends it to all the ports. As a result, only one port can talk at a time.
A switch looks a lot like a hub; it has a lot of ports in the front and usually has several small lights corresponding to each port. However, a switch is unlike a hub because it only makes a connection between the ports it needs to. A switch can have multiple connections at the same time. This allows a switch to be faster than a hub.
The most common network infrastructure services include:
Each computer on a network needs a unique identifier called an IP address. The IP address allows packets to be directed to the computer, much like a street address allows mail to be delivered to the correct house. An IP address follows a specific form: four groups of digits forming a number from 0 to 255. For example, a local IP address might be 192.168.2.50.
For convenience, a computer's IP address can be given by a server running the Dynamic Host Configuration Protocol (DHCP) service. DHCP automatically provides network settings to the computers on the network. With DHCP, there is no need to keep track of each computer's IP address.
DNS is a service that runs on a server, and it is like a phone book for computers, except that it stores IP addresses instead of phone numbers. Your computer talks to a DNS server every time you refer to another computer system with a name instead of an IP address. For example: www.edubuntu.org, wikipedia.org, and google.com are all DNS hostnames.
NTP is a service that runs on a server and allows other computers to synchronize their clocks. The server synchronizes with an extremely accurate atomic clock, and then the clients synchronize with the server.
A Web server answers queries using protocols such as HTTP, and sends content such as web pages back to clients. Your Web browser almost exclusively talks to Web servers.
A Web proxy is a service that runs on a server and accesses Web sites on behalf of the clients. A proxy can cache some data to allow faster repeated access to commonly accessed pages. A proxy can also restrict access to content that you deem inappropriate.
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| Choosing The Correct Installation Type |
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Chapter 2. Edubuntu Workstation |