Basic Networking

by B.MillsShow adapted fromwww.newboston.org

The purpose of a network is to share data

Local Area Networks (LANs) are restricted to rooms, buildings and smaller geographical areasLANs are often prohibited from outside (Internet) access. For example personalstudent information and grades are the property of LAN-based servers and cannot be Freely. The more exclusive the data is, the more likely it will be within a LAN environment.

MANs are similar to LANs but have a topology which may be determined by the type of databeing transferred. For example: research between universities or hospitals and other entities such as police or emergency services.

WANs are similar to MANs but have an topology greater than 30 miles. The most well-Known WAN is the Internet.

Your operating system won’t let other computers access your computer. You must go througha server. You can think of a server as both a security guard and translator. This is the basis of how the Internet works.

Servers are home to websites. Websites such as thenewboston.org are on a server. Serverscan be anywhere. Cebilingual.com’s server is located in California. The job of your browser is to use the http protocol and ask for files from the server. Thebrowser will also translate text and symbols so that you can read them (session layer)

In business, the ‘client’ is always the one who is receiving the ‘service’. Therefore, your computer is a ‘client’ because it is receiving files and data. If you are ‘giving’ the files, then you are the ‘host’. For example if you give a party at your house, you are the ‘host’ and youare ‘serving’ food and drinks.

NIC (Network Interface Card) connects to a computer’s motherboard. These days, NIC cardsare built into the motherboard.

Protocols are rules that are allowed in a conversation between nodes. In a typical humanconversation only one person talks at a time. If I say ‘hello’ then I expect your answer to be ‘hello’, ‘good morning’, hi, etc…. A common protocol for the Internet is ‘http’ (hypertext transfer protocol). For http, one person talks at a time and a response is expected.

In this example I ask the www.thenewboston.com server for a file called ‘index.php’ using the http protocol

Topology means: how your computer network is arranged. In the “Bus” arrangement Above, the ‘T’ is called a ‘terminator’ which means that when the signal has run along thebackbone ‘the wire in the middle’ the signal is killed so that it won’t keep bouncing back and forth and repeating itself.

In this topology, all the devices are connected to one main ‘ring’ . I may not look like a perfect ring after connecting all your devices but the signals will move in a ring pattern.A ring has no terminators. If you request a file, it will ‘ask’ each node until it finds the machinethat has the file (probably the server). Even after it finds the file, it will continue to ask all the nodes until the request returns to your machine.

This topology is the most popular and is used in most personal home networks. The routerIs the central device which connects all nodes. The router then connects all devices to the Internet. Routers are not expensive but the router is the weak point because if the routerfails, so does the network. The star network can easily be expanded.

This topology is the most complex. It is similar to driving a car: if one road is closed, you can take another road to your destination.

The OSI model gives a broad overview of networking and how data is passed from one nodeto another.

The Modem connects your network to the Internet

The router decides what path the data will take. For example if you are receiving a file fromGoogle , the router knows which computer to send it to.

Because the router has only a limited number of ports, a switch is an extension of the routerthat allows you to expand your network

Binary code is all the 0’s and 1’s that the computer understands but you don.tHere is an example of the number 19 in bianary code.Will the number 128 fit into 19? No! so we give it a 0. 64? No!, 32? No! . 16? Yes! So we give itA 1.

A basic IPv4 Internet IP address has 32 bits. Each of these 8bit sections are called Octets.