Session 8: Establishing an Electronic Network

In this section:

"Connect" is a very apt word for this section. What we're going to discuss is the what, why and how of computers that are connected together in networks. There is a lot to talk about:

What Is a Computer Network?
What Can a Network Do?
Networks and the Internet
Hardware
Software
Security
Costs
Administration
 

What is a Computer Network?

A computer network can be defined simply as "two or more computers connected and able to share data." This often takes the form of several computers hooked up to each other, a printer, and a central computer called a server.

A single computer hooked up to a printer is not a network because there is only one computer (Technically, I suppose a printer is a small computer, but for our purposes we'll talk about conventional desktop computers). This may be obvious, but what about the Internet -- is it a network? Well, yes and more. The Internet is actually a network of networks, but more about that later.

Luckily there is a name for a bunch of computers hooked up to each other and to one or more printers and/or servers: "LAN" for Local Area Network. A LAN is group of computers physically connected to each other and in close proximity. A classroom with 10 computers hooked up to a printer is a LAN. Classrooms hooked up to each other but in the same building is also considered a LAN -- just a bigger one.

LANs and WANs

Local Area Networks are most often considered to be groups of computers hooked up physically to each other and in close proximity. A WAN, or Wide Area Network is what you get if you use telecommunications to hook up several computers, or LANs. Many schools hooked up to other schools in a district form a WAN. Corporations using the Internet to link offices across the world are using WANs. We'll be concentrating on LANs here because they are the building blocks of every other kind of network and thus seem a good place to start.

What Can a Network Do?

So what do LAN's do, or more appropriately, what can they do?

Networking computers into a LAN enables them to share data between each other and sharing data is good. Like humans, computers work more efficiently when they work in groups, especially ones that communicate well.

For instance, without a LAN each computer in a lab would have to have its own printer. On a LAN computers can all share a single printer, which is considerably cheaper then buying a printer for each computer!

The primary role of a LAN is to facilitate:

LANs and the Internet

Here's the real icing on the cake of LANs. Once your computers are talking with each other, you can hook them all up to the Internet with a single connection (and a fast one at that). Instead of having a bunch of small, slow modems, one to a computer, you can have one big fast modem for every computer on the entire network to share.

LANs are the smallest network in the network of networks called the Internet. The Internet is made up of bunches of LANs hooked to big computers that make a very big WAN, the Internet. But it is just a question of scale. A classroom LAN is a small model of the entire Internet and all the same concepts apply.

(You could think of the Internet as a LAN for the planet Earth. The question then becomes, to what network will Earth be linked..?)

So what's an Intranet?

An Intranet is simply a private LAN or WAN. Intranets are most often used by corporations that want to use Web pages and databases to help their work flow, but don't want to use them on the publicly accessible Internet. Intranets are usually either not connected to the Internet at all or support only limited or one-way access.

Intranets bring up a fascinating fact about Web sites. Web sites don't have to be on the Internet! Web pages on the Internet are simply housed on big computers that are linked into the Net, but you can just as easily put a Web site on a small server, with some inexpensive Web server software, and have a private little Web site for your classroom or building--your own Intranet!

OK, lets come back down to earth and get real!

Some key reasons for hooking up a LAN to the Internet.

How Do You Hook Up a LAN to the Internet?

You don't, you get someone else to.

Really though, this is an important distinction. Networking is a profession and best left to professionals -- and it can be expensive. The professional may be your technical coordinator, the school's systems administrator, a private contractor, or your service provider. But no matter who it is, you'll need some conceptual understanding to talk about what you want, so here goes.

We're not talking about 28.8 modems (the most common personal modem as of this writing) anymore. 28.8 modems average 2k/sec. download times. Don't worry about what that means technically, just that it's normal home surfing speed. For LANs hooked up to the Net, we're talking about much bigger "pipes" to use a common metaphor -- much shorter download times. But why? Because when you hook up even five computers to the Net, you have to be ready for all of them to be using the Net at the same time, so that would require something at least 5 times faster then a 28.8 modem, or 5 different 28.8 modems. 30 computers would need the speed of 30, 28.8 modems. In reality you need even more speed because you want your LAN to have a connection to the Net that is faster than a silly old 28.8 modem. So you need a line that connects your LAN to a service provider via a really spiffy modem type contraption. A service provider is a company that maintains computers that are hooked directly to the Internet via a really BIG pipe that can handle multiple lines to LANs like yours.

Once you get a professional involved, you'll need to know a little about what kind of pipelines are out there and what they're called.

Specifically we're talking about:

Hardware

Wiring

Keep in mind that, for the most part, computers have to be connected physically by actual wires. As you look at existing LANs, or think about setting one up in your school, consider the wires. Where do they run? In the ceiling? The floor? The walls? How much construction, demolition, or rebuilding is it going to take to wire up all your computers? Where would the servers and the connection to the Net be physically located?

Another factor to keep in mind is that wires have a limit on the distance they can travel from their servers. Coax can run about 300 feet, twisted pair (phone lines) about 1000 feet before the signal degrades too much to use reliably.

Servers

A server is a normal computer running special software. Servers act as a central computer that can hold, share and route data to the computers on a LAN. Internet connections most often come through servers which route email and files to different machines, or act as a firewall for security purposes.

Routers, and Hubs

Different names, same general idea -- traffic cops for the data on a LAN. Routers forward packets of data to their destinations. The router makes decisions on where to route packets based on routing tables and routing protocols. Hubs are so named because they act like a regular hub. Imagine a bicycle wheel with the hub being a computer and the spokes being wires that go out to the computers on a LAN. A hub can have one big network line coming into it and then branch that line out to multiple computers.

Cards

Computers usually have to have cards to hook up to Networks. Sometimes, as with the very common Ethernet connection, the cards are already built in to your computer. Other times you have to buy cards and have them installed in each computer so they can hook up to the network. If you are installing older machines on your network, you'll need to plan for this cost.

Speed demons

Most computer use can be fit into categories that do not require fast expensive computers. Like word processing, basic graphic work, Internet searching, etc. But some labs find it educational and useful to buy one or two expensive fast speed demon computers, and limit them to graphic and multimedia work only. This is also a great way to expose students to what they might find out in the working world.

Mac vs. PC

The holy war is over between the Mac and PC. The Mac won. We know this because Windows 95 has a trash can and has almost nothing to do with DOS and command lines. These differences remain, but on an increasingly minor scale: There is more software available for the PC then the Mac, but it's mostly high end stuff. Macs are still easier to use and learn on and easier to use if you are creating a LAN. PCs are much more common in the real world. Macs are still better for artists and writers.

The Beauty of Internet is that it's almost entirely cross-platform. Email sent on one platform can be read on another. Web pages served on one can be browsed from another. So the decision should be based on what you like to use, because both Macs and PCs will do a fine job in any LAN.

In fact, LANs make it possible to have both Macs and PCs on the same LAN, and that's something to consider..

Software

You can set up a fine lab with just ClarisWorks (graphics, painting, word processing, database, spreadsheet, all rolled into one inexpensive, easy-to-learn and use application), Internet software (email, browsers) and a fast Internet connection.

While it's tempting to by lots of software, keep in mind that software is expensive, needs to be upgraded constantly, and you have to learn it before you can use it. Start with a basic package that has all the capabilities of ClarisWorks and then see what else you need as you go along.

Security

Hooking up a LAN to the Internet brings a whole host of security issues that are being played out in the press every day. While there is software and hardware that will filter out dangerous content most of the time, the best filters are HUMAN ones. By always having an adult in the room and making all Internet activity very structured from the start, you can keep things under control.

NOTE: Session 9 will be deal with this topic in more detail.

Costs

The buck stops here. Networks can be expensive and have a tendency to naturally get more expensive. The trick is to balance what you actually want to do against the thrill and excitement of a network's possibilities. There are some important points to remember when considering the cost of a network.

Who Will Run the Lab?

We've talked a lot about what LANs are and about setting them up, but what about once they are up and working? Like most things in life, starting is easy -- it's the long haul that can get difficult and LANs are no exception.

A LAN is like an Indy 500 race car, it needs constant pit-stops and tune-ups to run smoothly. Once you have installed a LAN you will have to think about the following things:

Records

Records of software serial numbers and licenses need to be filed, and emergency boot disks need to be made. System software needs to be kept track of and upgraded. Most LANs need to keep records of what is on each computer, upgrades installed, IP numbers for the Internet, who worked on the system when, and so forth.

Maintenance

A simple LAN (5-10 Macs with a printer) doesn't need a full time sysadmin, but it does need someone who is responsible for upgrades, problem solving and keeping track of what needs to be done, and what has been done.

Contracts

If you subcontract to outside vendors like service providers, computer supply stores, and consultants, these need to be tracked to make sure contracts are being honored.

Access

Someone has to decide when the lab is open, who gets keys, if it's used for community purposes, and so forth.

Rules

You'll need to set and enforce rules for the lab, because a lot of people are going to want to use it and expect it to be in good shape for them when they arrive. Windows must be shut in case of storms that cause water damage. Computers need to be kept cool (you may need air conditioners for the labs). And, most important of all, no food or drink near computers!

Staffing

All but the smallest LANs will need staff and someone will have to hire and supervise them.

Tech Coordinators

As we've learned, integrating computers into a school is multifaceted. A LAN will be integral to the process and those who oversee LANs should work closely with any technology coordinators so that the network can be used efficiently.

Well, I'm completely un-connected, so let's move onto Apply and get some work done!

Page authors: Caleb Clark and Bob Hoffman
URL: edweb.sdsu.edu/courses/edtec596r/module8/intro.html
Last updated: February 13, 1998