Networks are usually classified using three properties: Topology, Protocol, and Architecture.

Topology specifies the geometric arrangement of the network. Common topologies are a bus, ring, and star. A bus topology means that each computer on the network is attached to a common central cable, called a bus or backbone. This is a rather simple network to set up. Ethernets use this topology. A ring topology means that each computer is connected to two others, and they arranged in a ring shape. These are difficult to set up, but offer high bandwidth. A star topology means all computers on the network are connected to a central hub. These are easy to set up, but bottlenecks can occur because all data must pass through the hub. You can consult the diagram below to see these three topologies:

Protocol specifies a common set of rules and signals the computers on the network use to communicate. There are many protocols, each having advantages over others. Let’s run through the common ones:

• TCP/IP : Transmission Control Protocol / Internet Protocol. This was originally developed by the Defense Department of the US to allow dissimilar computers to talk. Today, as many of us know, this protocol is used as the basis for the internet. Because it must span such large distances and cross multiple, smaller networks, TCP/IP is a routable protocol, meaning it can send data through a router on its way to its destination. In the long run, this slows things down a little, but this ability makes it very flexible for large networks.
  
• IPX/SPX: Developed by Novell for use with its NetWare NOS, but Microsoft built compatibility into both NT and Windows 9x. IPX is like an optimized TCP/IP. It, too, is a routable protocol, making it handy for large networks, but it allows quicker access over the network than TCP/IP. The downfall is that it doesn’t work well over analog phone lines. IPX continually checks the status of transmission to be sure all the data arrives. This requires extra bandwidth, where analog phone lines don’t have much to begin with. This results in slow access. Of course, the data is more reliable with IPX.
  
• NetBEUI : Designed for small LANs, this protocol developed by Microsoft is quite fast. It lacks the addressing overhead of TCP/IP and IPX, which means it can only be used on LANs. You cannot access networks via a router.

Architecture refers to one of the two major types of network architecture: Peer-to-peer or client/server. In a Peer-to-Peer networking configuration, there is no server, and computers simply connect with each other in a workgroup to share files, printers, and Internet access. This is most commonly found in home configurations, and is only practical for workgroups of a dozen or less computers. In a client/server network, there is usually an NT Domain Controller, which all of the computers log on to. This server can provide various services, including centrally routed Internet Access, mail (including e-mail), file sharing, and printer access, as well as ensuring security across the network. This is most commonly found in corporate configurations, where network security is essential.

Now that you have a basic understanding of networks, we’ll learn about the type of network most people will want to setup, a Local-Area Network.