Proper Network Design

Setting up a network of computers is a lot of fun, even if you're getting paid to do the job. But maintaining, and using, a properly designed and setup network is a lot more fun than maintaining, and using, an improperly designed one. Be aware of some common pitfalls. Proper design, in many cases, is cheaper, and less complex, in the long run.

• Cabling. Making your own Ethernet cables may look like fun, but it's not.
  
• Grouping. Setting up a domain is not for everybody, but it will make your life easier in many ways.
  
• Networking. Using a NAT router for connecting just one computer to the Internet, or for connecting just 2 computers to each other, is cheaper and safer in the long term.
  
• Wired or Wireless LAN? Using WiFi is great - when you truly need it. But know the limitations.
  
• Firewire / USB Networking. In a pinch, a Firewire or USB port can work as an emergency network device. But they aren't good long term solutions.
  

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Ethernet Cabling - It's Not A Good First Time Project
An Ethernet cable is more than a simple group of small wires - it's actually an electrical system in its own right. The specifications for a 10M Ethernet cable are pretty complex - for 100M cable, you have to be more careful. And Gigabit Ethernet cable requires special equipment.

If you're a professional, and setting up a large office, hire an experienced and licensed electrician. If you're setting up your own small network, whether for a small office or for your home, and you're just starting with Computer Networking, buy premade, and tested, cables at a computer store.

Don't learn computer networking starting with making your own cables. Setting up an infrastructure, using reliable cabling, is cheaper, and easier in every respect. Don't start with do-it-yourself Ethernet cabling, when you're setting up a network.

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Domain vs Workgroup - A Little Effort Can Go A Long Way

Every Windows computer will act as a server, but only computers running a true server Operating System - Windows 2000 Server, or Server 2003 - can provide a domain. And setting up a domain is not a good project for your first network. But domains have their advantages as well as disadvantages.

If you have any network expertise, and a server operating system, consider setting up a domain. It's good for you, in the long run.

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Networking Computers Is Cheaper, and Simpler, With a NAT Router
If you have one computer, sitting in your office, and connected to nothing, you have just one computer. If you connect that computer to the Internet, or to another computer, you have a piece of, or the beginning of, a network.

• The simplest way to connect your single computer, to the Internet, is to connect the modem (Cable, dial-up, or DSL), externally, to your computer. Or install the modem internally.
  
• The simplest way to connect your two computers, to each other, is to connect them using a cross-over cable. Using a pair of WiFi adapters, one in each computer, you could eliminate the Ethernet cable, and have an ad-hoc WiFi network.
  

In neither case is this true, in the long term.

• Using a NAT router to connect as few as one (as well as multiple) computers, to your Internet service, is an essential component in layered security.
  
• Using a NAT router to share Internet service, between as few as two (as well as multiple) computers, is almost as cheap as using ICS. And it's far simpler. ICS was a good idea long ago, but it's not today.
  
• Using a NAT router to connect your computers, and / or to share your Internet service, is easily scalable. When you get your second (or third or whatever) computer, just connect it to an available router port. How do you do that with ICS and a cross-over cable?
  

When you get your first computer, buy your first NAT router. And make sure the router can share the Internet service.

• If the Internet service is dialup, make sure that you get an external dialup modem, and a router capable of handling dialup.
• If the Internet service is broadband, cable or DSL, make sure that you get a broadband modem with an Ethernet port. If the modem only has a USB port, get a better modem.

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Choosing A Wired or Wireless LAN Is An Important Decision
When you setup a network of computers, in your home or small office, a mass of Ethernet cables running everywhere can be a problem. WiFi, or Wireless networking, can provide relief from the mass of cables. But WiFi is NOT a replacement for Ethernet, for many reasons.

• Scalability. With a 100M Ethernet cable, you could have up to 200M of data flow (with send and receive simultaneously), between a single pair of computers. Each pair of computers in your office can conduct a separate, yet simultaneous, 200M conversation.
  
  With 54M WiFi, all of the computers in your home or office, and all of the computers in your neighbors home or office, will all share the same 54M channel. Actually, there are 3 54M channels - but if you have even 1 neighbor, chances are that you'll have more than 3, so you'll have to share with at least one other network. And all of your computers will share that one 54M channel. The 54M channel is not a maximum - a 108M channel is a possibility. But there are limitations to that possibility.
  
  And there are other factors which will prevent you from getting an actual 54M, let alone 108M, of data flow.
  
  
• Security. Ethernet cables stay in your home or office - when you lock your door, your cables, and computers, are secure. The WiFi signal, on the other hand, travels thru your walls, and down the block, to your neighbors computers. You have to use extra security precautions, with a WiFi LAN.
  
  
• Stability. Your WiFi neighbors will come and go, constantly. You have WiFi devices politely, and impolitely, sharing the channel. And, you'll have noise on the channel. Noise can come from many electronic sources.
  
  
  
  • Baby monitors.
    
  • Computers.
    
  • Cordless phones.
    
  • Microwave ovens.
    
  • Wireless stereo speakers.
    
  
  

If you truly need WiFi, then use it. The convenience of surfing the Internet from your bedroom is great. But know the limitations of WiFi, before investing a lot of time, and money, needlessly. For many LANs, Ethernet cabling will always be a better solution, excepting for one specific electrical code and safety issue.

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Firewire / USB Networking
Ethernet and WiFi are two dominant standards in networking. Ethernet for massive bandwidth (10G networks are coming closer), and WiFi for convenience. They both have tradeoffs.

Now just about any desktop computer that you may buy today will have an onboard Ethernet port. Most laptops that you buy will too, and most laptops will also have WiFi. And both desktop and laptop computers have a third networking possibility - Personal Area Networking, aka Firewire / USB. Firewire and USB are competing standards. Most computers will have one, if not both, ports. These ports allow you to connect most modern computer peripherals, such as a keyboard, pointing device (pka mouse), even a portable mass storage device (pka disk drive).

Properly designed Firewire / USB devices will use drivers already installed in Windows, and will support hot plugging. You'll be able to connect or disconnect such a device with the system running, at a moments notice.

And that's the strength of Personal Area Networks - the ability to attach and remove any accessory to your computer at will.

Now a PAN is a client (peripheral) - server (computer) relationship. The client attaches to the server (peripheral to computer). Networking computers is more or less a peer - peer relationship. But it's possible to buy a Firewire or USB cable, with an embedded hub, that will act like a client to the PAN bus, and like a peer to the networking stack in the operating system. With a special cable, you can setup a PAN between two computers.

So if one or more computers don't have an Ethernet or WiFi adapter, you can setup a physical network conveniently. But you will still have to define the logical network between the two computers. Setting up an IP based network, to share files between 2 computers, requires a significant amount of effort. That's in addition to loading the drivers to support the PAN itself. And there's no absolute guarantee that any PAN driver will work, between any 2 computers.

Ethernet and WiFi, on the other hand, are de facto standards for networking computers. They are designed for long term connection of computers. And there are a lot of people who know how to install, configure, and support Ethernet and WiFi.

And what if you have another device connected to the PAN bus on your computer? If you have a USB keyboard / mouse, and you're using a USB based network to connect to the Internet, your Internet access will have to share activity with your typing and cursor movement. The Ethernet bus was designed for inter computer connections, and is dedicated to that purpose.

In short, if you have an emergency, and can't open up your computer to install an Ethernet adapter, AND both computers in question have Firewire or USB ports, AND you have a Firewire or USB networking hub / cable, using Firewire or USB is a good short term solution. But in the long run, using Ethernet or WiFi to connect your computers makes more sense.

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