4.9 LABORATORY - NETWORKING

Purpose: To expose you to the architecture and components of a modern computer network.

Objectives: To be able to set up a switch and computers to communicate over an Intranet network.

Background:

Computers can be connected via a network. At a minimum this requires a network card in at least two computers and a connecting cable between them. These computers can then pass packets of information back and forth for basic communication. This type of connection is commonly used by people playing games such as Quake at home. A more mature network, like that found in a factory, must be more sophistocated.

The most fundamental concept in a network is the data packets and the protocol for exchanging them. The current Internet protocol is called IPV4 (this will be replaced by IPV6 in the near future). In this protocol each client on a network has a 4 byte (0-255) address, normally shown in the form ‘aaa.bbb.ccc.ddd’. In our case the university is a ‘class B’, so it owns all addresses that start with ‘148.61.ccc.ddd’. Most engineering students use a ‘class C’ network with the addresses ‘148.61.104.ddd’. In theory there are up to 256 clients on the engineering network. In practice some of these addresses are used for network housekeeping. For example the following addresses are used,

148.61.104.1 - this is the router/switch to other networks 148.61.104.254 - this is the gateway to other networks

If a network address is not used, it can be used by a normal network device, such as a computer or printer. There are two ways to assign these statically or dynamically. In a static connection the address can only be used by one machine. In a dynamic connection the addresses are assigned and release semi-randomly to network clients as the connect and disconnect from the network. Static IP addresses are primarily designed for computers that are always on, and are acting as servers on the network. Dynamic IP addresses are primarily used for computers that are only clients on the network. Some examples of static IP addresses on the network are:

148.61.104.215 - claymore.engineer.gvsu.edu 148.61.104.226 - excalibur.engineer.gvsu.edu 148.61.104.??? - falcon.engineer.gvsu.edu etc..

Most computers on the network are named, such as ‘gvsu.edu’. When a user enters this name into the computer, it must be converted to a network number. This is done by a ‘domain name server’ (DNS). There are two DNS servers at GVSU (148.61.1.10 and 148.61.1.15). These servers keep all of the names for computers at GVSU, and also provide links to computers at other sites so that their names and numbers can