Timothy
Parker Consulting Incorporated
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Peer-to-Peer Networks In the last Help Desk we looked at the plethora of IRQ, DMA, and I/O addresses that have to be worried about with most computer cards. All of that was to lead into the subject of installing a network (cards and all) in this and the next column. While a network install may seem simple, you would be surprised at the number of VARs who have no clue how to go about installing network interface cards, configure a network, and run the cabling. (Which is why some of us get paid really well to do a relatively simple task!) We have a whole bunch of issues to deal with to install a network, including what type of network we need, what kind of clients and servers we’ll use, what type of network operating systems and network protocols will work, which network cards to use, choosing and connecting the cables, and troubleshooting the network. Sounds like a lot, but it really goes pretty quickly. Installing a network can seem overwhelming the first time you do it, but it’s really straight-forward as long as you proceed methodically. Let’s start by choosing a network type to install in this series (we’ll look at several others in columns next year). Since Windows is the operating system of dominance for most users, that’s what we’ll start with. We will configure a simple network of Windows 95 and Windows 3.X machines, all designed to allow file and resource sharing. File sharing means one machine can transfer files to any other, and resource sharing means that a printer attached to one machine can be used by everyone else, or any other device like a scanner can be accessed from across a network. Since Windows 95 comes with network support built in, as does Windows 3.11, we’ll assume most of the machines are of these two types. Just to make things interesting, we’ll see how to add Windows 3.0 and 3.1, as well as DOS, OS/2, and Unix machines to this network later. All these machines are going to be equal to each other as far as the users are concerned. In other words, no single machine is the server. (If one was, we’d have a client-server network.) Instead, since the machines are all equals, this is a peer-to-peer network, which is the simplest type of network to install. No server means a lot less hassles for installers. Since we have a peer-to-peer network, we need no special operating system to handle client-server operations (such as Novell NetWare). Instead, Windows has all the software we need. The next decision is the network protocol to use. Windows supports a bunch of network protocols, but there are really only three to worry about. NetBIOS (Network Basic Input/Output Syustem) and NetBEUI (NetBIOS Extended User Interface) are Microsoft’s network protocols from Windows 3.11 (and several other network systems, too). NetBEUI and NetBIOS really only work among Microsoft machines, and they are not that feature-rich, so we’ll ignore them. IPX/SPX (Internet Packet Exchange/Sequenced Packet Exchange) is the network protocol used by Novell NetWare, and since we don’t need a NetWare server, we’ll skip IPX/SPX. This leaves the most popular network protocol in the world, TCP/IP (Transmission Control Protocol/Internet Protocol). TCP/IP is used on the Internet, and most networks that have Unix systems on them. It’s a much wider support protocol than IPX/SPX, and makes an excellent choice for both peer-to-peer and client-server networks. (I wrote a series of articles last year on TCP/IP that you may want to refer to, or you can skip the technical stuff and just install it!) So we are going to have a TCP/IP peer-to-peer network. Next, we choose the type of cabling and connectors we will use to run the network to each machine. There are a number of choices, but since we are not installing for a large corporation that needs to support thousands of workstations, we can ignore all the expensive ones. This leaves two setups we need to choose between. The first is called by a number of names: 10Base2, thin-net, and thin coax. The name 10Base2 refers to a 10Mbps network with a maximum cable run of 200 meters. 10Base2 cable looks like television coaxial cable (which can be used, although there are better choices). The ends are a special connector called a BNC plug. A 10Base2 network has thin coaxial cable (actually called RJ-58 or Thin Ethernet) running from one machine to another in a long chain, so this type of network is a serial design. Each machine has a T-shaped connector on the network card which has two lengths of cable to the two neighbouring machines, except the two end machines which have one cable and a terminating plug which holds a resistor. The reasonable alternative to 10Base2 is 10BaseT which uses twisted pair cables, like a wide telephone cable. There are usually four pairs of wires in a 10BaseT cable. 10BaseT cables run from a jack on the back of the network card to a device called a hub, which handles rerouting network traffic to the rest of the network. Since each machine has only one cable, everything is centered around the hub which must be within reach of all machines. Two or more hubs can be wired together (either with 10BaseT or 10Base2 cables) to expand the reach of the network. The end plug on 10BaseT wires is wider than a telephone plug, although it looks similar, and is called an RJ45 or RJ-11 plug, depending on the number of wires. A 10BaseT network is usually easier to install as you need only a single wire from each machine to the hub. Most inexpensive network interface cards have only an RJ-45 plug, with a BNC connector for 10Base2 networks costing more. 10BaseT cables are easier to route around walls, ceilings, and gather into bunches than 10Base2 cables, although the latter are not too bad. The problem with 10BaseT is that it requires a hub or switch which adds to the cost, and it is a little slower and has less total length than a 10Base2 network. You can mix 10BaseT and 10Base2 on the same network, in which case a hub is connected at some point in the 10Base2 cable and the 10BaseT machines connect to the hub. The network doesn’t care where each machine on the network is. We’ll install a mix of 10BaseT and 10Base2 just to cover all the bases. The last issue is a hub. These handle routing for 10baseT machines and come in two flavors: unmanaged and managed. Managed hubs are much more expensive but are a little more talented and can be administered from a central network. Since we’re working inexpensively, we’ll choose an unmanaged hub. We will look at hubs and switches in more detail in a later column. Finally, we will buy any network interface cards that support 10BaseT and 10Base2 (or any combination thereof) we can get a good price for, and next column we’ll install all these goodies. |
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