If there's more than one computer in your home or office, connecting them together to form a network can make using them more convenient, faster, and less expensive. When your computers are part of a LAN (local-area network), you can quickly move files among them, share a single Internet connection, and let them all share a single printer. Also, many games include network play modes, letting you test your mettle against other players. Without a network, each computer is an isolated island of information. As part of a network, your computers can share resources and information like never before.
The computers in a network don't even have to run the same OS (operating system): You can include a mix of Windows PCs, Macintosh computers, Unix systems, and others.
Ethernet, as part of the category of wired networks, is the least expensive way to create a LAN. It's also reliable and easy to set up.
1. An Ethernet jack is built into most computers. Chances are, your desktop or notebook computer already has an Ethernet jack, so it's ready to plug in to a wired network. If not, you can add one: Ethernet add-on cards are available that work with PCI (Peripheral Component Interconnect), USB (Universal Serial Bus), PC Card, CF (CompactFlash), and practically any other free port your computer might have. PCI Ethernet cards are the least expensive option; you can often find them for less than $10 from manufacturers such as D-Link (http://www.dlink.com) and Belkin (http://www.belkin.com).
2. To network more than two computers, you will need an Ethernet hub. The hub acts as a traffic cop, coordinating communication among all the devices on the network. Each computer's Ethernet jack connects to a port on the hub via a CAT 5 (Category 5) cable with RJ-45 connectors at both ends. (RJ-45 connectors look like a telephone plug, only larger.) CAT 5 cables can be wired in two ways: straight-through and crossover. A straight-through cable is the type you'll need to connect a computer to an Ethernet hub. Manufacturers that sell hubs include D-Link, Belkin, Kensington (http://www.kensington.com), and Adaptec (http://www.adaptec.com).
But computers aren't the only devices that can be part of a network; if you have a DSL (Digital Subscriber Line) or cable modem, you can share your fast Internet connection among several computers by connecting a router to the network. In addition, you can make some types of printers part of your network. We'll discuss these two options in greater detail in the "Share An Internet Connection" and "Share Printers" sections of this article.
3. When choosing a hub, count the ports. Ethernet hubs have a number of ports (often four or eight), which dictate the maximum number of computers (or other devices) you can connect to your network. Make sure the hub you choose has enough ports for the amount of computers and devices you want to add to your network. If you have two computers in your home, along with a printer and a cable modem, a four-port hub provides just enough space.
If your network outgrows the hub down the road, you can add a second hub, linking the two together. However, two is the limit because Ethernet's traffic rules specify that only two hubs can connect together in a network.
4. Speed up busy networks with a switched hub. Using a standard Ethernet hub, all the information that moves on the network is broadcast to every computer on the network. For instance, if computer A is sending a large file to computer B, then computers C, D, and E "see" it going by and have less bandwidth.
On small personal networks, this arrangement is sufficient, but busier networks will greatly benefit by using a switched hub. A switched hub routes data only to the computer that it's intended for. That way, as in the example we just used, computers C, D, and E don't have to see the extraneous traffic, thereby improving network performance and the amount bandwidth available for those machines.
5. Consider Ethernet speed. As technology has evolved, Ethernet has become faster. An older but still popular version, 10Base-T, can transfer data at a respectable 10Mbps (megabits per second). 100Base-T is a newer version, available in many new computers, that operates at 100Mbps. (Another, much faster version, 1000Base-T, also known as Gigabit Ethernet, is on the horizon.)
The good news is that the three are compatible: A computer with 10Base-T can network to a computer with 100Base-T, although not at the fastest speed. The Ethernet hub sets the lowest common denominator: If your hub is limited to 10Base-T, computers with 100Base-T will have to slow down. If you have two or more computers that handle 100Base-T, you can boost the network performance by using a 100Base-T hub. A 10/100Base-T hub can talk to devices at both speeds.
6. Network two computers without a hub. For a simple, small network of just two computers, connect the two Ethernet jacks directly together with a crossover, instead of a straight-through, CAT 5 cable. The two computers will be able to share files, but you won't be able to connect a network-capable printer or broadband (DSL or cable) modem.
7. 100 meters is the limit. The computers in a wired network don't have to be particularly close to one another. You could put a hub in the den, a PC in the kitchen, and a Macintosh in the kids' room. The specifications for 10Base-T and 100Base-T indicate that the maximum cable length can be 100 meters, which is 328 feet. In practice, the real limitation is not the length of the cable but the signal level, and longer cables mean greater signal loss. You may be able to get away with greater distances by using high-quality cable, though.
8. Avoid interference. You can run Ethernet cables inside walls, in the attic, and under the house. Building a wired network in an existing house may mean boring discreet holes in walls to get a cable where you want it to go. If you're building a new house or office, consider running conduit (thin tubes that you can push wires through later) behind the walls from a central "hub" room to the other rooms where you might eventually want to put a computer.
Don't run Ethernet cables parallel to electrical lines for long stretches, near florescent lighting fixtures, or close to other sources of strong electromagnetic interference. Also, don't let Ethernet cables coil. A coiled cable can create an electromagnetic field that disrupts the very data it's supposed to transfer.
Another option for setting up LANs has gained tremendous popularity in the past year: Wi-Fi. Short for wireless fidelity, a Wi-Fi network provides more flexibility to move around than a wired network. However, it's more expensive to build.
9. You'll need a wireless access card and a hub. In order to access a wireless network, each computer, PDA (personal digital assistant), or other device needs a Wi-Fi access card and a small radio transceiver that connects to the computer's PC Card slot, PCI slot, or USB port. They also need to be in the vicinity of a Wi-Fi access point (also known as a wireless hub or, in public places, a "hotspot").
You can install a wireless access point in your home or office that will let you access the network from any properly equipped computer (such as a notebook or PDA) in the area, rather than being tethered to a wire. Many airports, coffee shops, hotels, and conference centers offer Wi-Fi access (free or for a fee) so you can take that notebook or PDA with you for Internet access on the go.
Manufacturers that sell the type of equipment needed to set up a wireless access point include D-Link, Hawking Technology (http://www.hawkingtech.com), Linksys (http://www.linksys.com), and NETGEAR (http://www.netgear.com).
10. 200 feet, more or less. Wi-Fi access points generally provide access to computers in a 150- to 300-foot radius, which is typically up to a few rooms away. As you move farther away from the access point, the connection becomes slower. Walls and other obstructions, especially concrete and steel beams, further limit wireless range. If you need access in a larger vicinity, many Wi-Fi access points may work with external antennas that can boost their signal somewhat.
11. The two major wireless networking specifications. The most popular version is 802.11b, which has been around the longest and has the support of the most public hotspots. Cards that add 802.11b access to notebooks and PDAs are also inexpensive (from $30 to $50). The new and up-and-coming version that will eventually replace 802.11b is 802.11g, which is about five times faster than 802.11b, but is still backward-compatible with it, making 802.11g the ideal choice for many people.
If your notebook has an 802.11g card but the local hotspot uses 802.11b, your card will then use the 802.11b specification instead. Similarly, if your notebook has an 802.11b card but the hotspot uses 802.11g, you'll still be able to get Internet access, but not at the full speed of 802.11g. 802.11g cards for notebooks and PDAs typically cost from $70 to $100. Manufacturers that sell these types of cards include D-Link, Linksys, and NETGEAR.
12. 802.11a, the other wireless networking specification. A third version of Wi-Fi, 802.11a, also is available but private businesses are typically the only ones that use it. In fact, 802.11a is rarely used in hotels, airports, and other hotspots that are open to the public. If you plan to access the Internet from public places, don't worry about 802.11a. But if you need to get on the network at a business that uses version 802.11a, you'll need a compatible card because 802.11b and 802.11g cards aren't compatible with 802.11a access points.
If you want to cover all of the bases, you can get a card that handles all three 802.11 specifications. At $200 or more, these cards are more expensive than other cards but assure that you'll have wireless network access in the greatest number of situations. If you don't need access to a specific 802.11a network, opt for 802.11g or, if you're on a tight budget, 802.11b.
13. Update your firmware. Most hardware manufacturers released their wireless access cards and access point equipment before the final versions of the networking protocols they use were set in stone. As a result, wireless hardware--whether you've been using it for months or just bought it today--may not know how to use the most recent versions of the protocols. This can cause problems such as slow transfers and incompatibility with other wireless devices.
The solution is simple: Upgrade the firmware in the wireless hardware. Firmware is software that manufacturers build into hardware, and just like any software, you can upgrade firmware. Your access point equipment's setup screen should tell you what firmware version it is currently running. Check the manufacturer's Web site to see if a newer version of the firmware is available.
14. Steps for updating firmware. Upgrading firmware is usually straightforward: If a new version is available, you'll have to download and run an installer program, which will write the new firmware version to the access point equipment's permanent memory. The program may take several minutes to run, so once it begins, don't turn off the computer or access point equipment until the program indicates that the new firmware version successfully installed. Interrupting the process could leave your access point equipment comatose, with partially installed firmware. When the firmware upgrade is done, you can delete the installer program.
15. Before taking a trip, gather your maps and lists of Wi-Fi hotspots. If you want Internet access while you're out of town, get a list of Wi-Fi hotspots before you go. The FreeSpot Directory (http://www.wififreespot.com) offers lists of free access points across the country, and WiFinder (http://www.wifinder.com) presents lists of free and commercial hotspots around the world. There also are Web sites devoted to publishing hotspots for individual cities. For example, the Bay Area Wireless Users Group's site (http://www.bawug.org) has a list of free Wi-Fi cafes in San Francisco and NYCwireless (http://www.nycwireless.net) posts a list of free hotspots in New York City.
Now that you've set up your network, it's time to address the nitty-gritty details involved in running a network.
16. Each networked machine needs an address. You can use many different protocols on a LAN to facilitate communication among computers and devices, but the most common by far is TCP/IP (Transfer Control Protocol/Internet Protocol), a combination of the same protocols used on the Internet.
Each computer or device on your network needs its own address. Small networks often have an address similar to 192.168.1. x (four numbers separated by periods), where x represents the number (from 1 to 254) assigned to a specific computer or device on the network. For instance, because the number 1 is usually reserved for the router or access point equipment on a network, the address is our example would be 192.168.1.1. Beyond that, you can make the final digit whatever you want when configuring the network settings on each machine, as long as no two have the same address.
17. Let the router do the addressing. If an Ethernet hub is what ties your network together, you'll have to set the machines' addresses yourself. But if there's a router (which is necessary for sharing an Internet connection) or a wireless access point device on the network, you can have it handle the addressing process.
Just configure the router or wireless access point device and each computer to use DHCP (Dynamic Host Configuration Proto-col). Then, the router will manage your machines' IP addresses and other network configuration details. Plus, there's another benefit: If you want to add another computer to the LAN (if a friend visits with her notebook, for instance), the additional computer will work automatically without any extra configuration.
18. Set up a home server. If you have an extra PC sitting around (even an older model), consider making a network server out of it. As a server, it can do some of the work for the other computers on the LAN.
For example, you could connect a printer to the older PC and use it as a print server. Or, you might decide to connect the older PC to a DSL or cable modem, then install a software router, and turn it into an Internet firewall/router. Or, load the older PC's hard drive with files that the other computers need access to, and it can serve your network as a file server. Yes, even an older PC can handle all of these tasks so don't let its potential go to waste.
19. Back up your data. If you're like most of us, you probably don't back up your data as often as you should--truthfully, few people do. You can use a LAN to easily back up data, protecting it in the event of a hard drive crash. Just copy your important files (such as your Documents And Settings folder in Windows) to another computer on the network once a day, and you have a backup without the hassle of burning data onto CD-RWs (CD-rewriteables) or swapping floppy diskettes.
Large directories can take a long time to transfer (especially over slower 10Base-T or 802.11b connections), so you should consider starting the backup first thing in the morning or, if you leave your computers on at night, at the end of the day. And make sure there's enough space on the destination computer's hard drive.
Computers aren't the only machines that you can include on a network; you can make printers a part of your wired or wireless network, too. The biggest benefit in doing so is that you can share a single printer among several computers on the network.
20. Some printers have built-in networking. Rather than (or in addition to) having a USB or parallel port as a way to connect to a single computer, a printer with networking capabilities has a 10Base-T jack. Connect this type of printer to your Ethernet hub and, after you complete some configuration tasks, all of the computers on your network will be able to use that printer.
In Windows XP, open the Control Panel (from the Start menu), click Printers And Other Hardware, and then click Add A Printer. When the Add Printer Wizard appears on-screen, click Next, choose the network printer option (rather than the local printer option), click Next, select the radio button next to Browse For A Printer, and click Next again. Complete the process by selecting the appropriate printer and following the steps the wizard presents on-screen.
In Windows 98, open the Control Panel (from the Start menu), double-click the Printers icon, and then double-click Add Printer. When the Add Printer Wizard appears on-screen, click Next, select the radio button next to Network Printer, click Next, and click the Browse button. Complete the process by selecting the appropriate printer and following the steps the wizard presents on-screen.
Because printers with networking capabilities typically cost more than printers without built-in networking, businesses are often the ones that use them. Some printer models even include wireless networking capabilities. Manufacturers that sell printers with networking capabilities include Hewlett-Packard (http://www.hp.com), Canon (http://www.usa.canon.com), and Xerox (http://www.xerox.com).
21. Add network support to the printer you already have. A hardware add-on might be able to add networking support to your printer. Check the printer manufacturer's Web site for Ethernet or wireless networking add-on devices for your printer. A print server such as the Linksys Instant Wireless PrintServer ($130) or D-Link DP-311P Wireless Print Server ($149) can add wireless networking to virtually any printer.
22. Extend your network's printer sharing privileges. Even if a printer connects directly to a single computer, you may be able to share it on the network using settings available via your OS.
To share a printer that's connected to a PC running WinXP, open the Control Panel, click Printers And Other Hardware, click Printers And Faxes, right-click the icon representing the printer you want to share, and choose Sharing. To share a printer that's connected to a PC running Win98, open the Control Panel, double-click the Printers icon, right-click the icon representing the printer you want to share, and choose Sharing.
Sharing a broadband Internet connection, such as DSL or a cable modem, is one of the best reasons to create a home LAN.
23. Read the terms of service first. Your ISP's (Internet service pro-vider's) terms of service contract may have restrictions against individuals using one Internet connection for multiple computers. Because of this potential roadblock, you should read the contract's fine print or contact your ISP before setting up this type of capability on your LAN.
24. A router is necessary for the job. To share a cable modem or DSL connection among several computers, you'll need a router. The cable/DSL modem must connect to the router, which sends Internet packets to the appropriate computer. Many inexpensive hardware routers double as Ethernet hubs; that is, you can connect your computers directly to Ethernet ports on the router, so you won't need a separate Ethernet hub.
25. Consider a software router option. If you want to share an Internet connection and already have an Ethernet hub, you can use a software router instead of buying more hardware. A software router is a program that runs on one of the computers on the LAN, providing the other machines with access to the Internet. In order for this arrangement to work, however, the computer with the software router must be "on" for the other computers to have Internet access. A couple of examples of software routers for Windows include WinGate from Deerfield.com ($49.95, license for three users; http://www.wingate.com) and WinRoute Lite from Kerio ($79, license for three users; http://www.kerio.com).
26. A firewall is highly recommended. Most hardware and software routers include some type of firewall (software or hardware that limits access from outside sources). To protect your network (and all the data it contains), make sure you choose a router that includes a firewall and learn how to properly enable it. A DSL and cable connection is online 24 hours a day, 7 days a week (unless you unplug it), potentially giving crackers unlimited access to the computers on your LAN.
A firewall is the first line of defense that prevents many types of cracking attempts. Without one, unscrupulous Internet users could download your private files, access financial records, delete your data, or even print to your printer. In order to keep your system secure, you should periodically check for updates to the firewall software or firmware. It's a good idea to visit the manufacturer's Web site once a month to check for updates. If one is available, download and install it immediately.
If something goes wrong with your wired network, these tips can help you get it running again quickly.
27. Look for the light. Most Ethernet ports (on the PC, hub, etc.) have a "link" bulb that will light up when a good connection is established. If the link light doesn't glow or blink as soon as you've made a connection, it's possible that the cable is bad or you've used the wrong type of cable. For instance, perhaps you used a straight-through cable when a crossover cable is necessary.
In addition, a problem with the Ethernet driver on a PC also might keep the light from glowing. To resolve this type of problem, either check the manufacturer's Web site to see if a better Ethernet driver is available for your network and/or equipment or uninstall and reinstall the driver to see if that helps.
28. Reconnect lost connections. If a single computer with an Ethernet connection unexpectedly loses its connection to the network, first check the link lights on the Ethernet card (called a NIC [network interface card]) and hub to make sure that there is still a connection. If both are lit, the two are connected correctly.
Next, try rebooting the computer to see if that solves the problem. If not, incorrect networking settings are the most likely source of the problem. To check the settings in WinXP, open the Control Panel, click Network And Internet Connections, and then click Network Connections. In Win98, open the Control Panel and double-click the Network icon.
If several computers unexpectedly lose their connection to an Ethernet network, verify that the hub has power. If it does, try resetting the hub by turning it off, waiting a few seconds, and turning it back on.
29. Watch out for collisions. Your Ethernet hub should have another light labeled "Collisions." Under normal circumstances, the Collisions light should remain dark or maybe flicker a few times each minute. If it flickers constantly, there's a serious problem that's slowing down your network traffic. Perhaps a cable is over the 100-meter limit or another one of 10Base-T's traffic rules is broken. But these typically aren't problems for home and small-office networks, which tend to be simple enough to avoid such issues.
30. Revive your Internet connection. If the computers on your LAN can't access the Internet, but they can still see each other, then there's obviously a problem with the DSL or cable modem or router. Simply restarting them may solve the problem. If your modem and router have reset buttons, press them; if not, unplug them, wait a few seconds, and then plug them back in. Then, once you wait a few minutes for the modem to reset, try accessing the Internet again. If the connection is still down, check the status lights on the modem to make sure the connection to your ISP is working. (These lights should be labeled Sync, Cable, or something similar.)
Wireless networking is convenient for many reasons. For one thing, you won't have to crawl under the house to pull wires through holes in the walls. However, because of the nature of wireless LAN, its users must understand security and privacy implications in order to find ways to protect their data and equipment.
31. Protect your privacy. Your privacy should be a special concern when you are using a wireless network. Information sent wirelessly--including word processor documents, printer output, email correspondence, Web forms, and more--can be intercepted by anyone within radio range. WEP (Wireless Encryption Protocol), a standard system for encrypting wireless traffic, is available via most wireless access point equipment but is often disabled by default. Read the users manual bundled with the equipment to find out how to enable encryption.
32. Can outsiders access your network? Unless your wireless hub is configured properly, anyone within radio range can use your wireless network to browse through your files. Each wireless access point has a SSID (Service Set Identifier), a code that other machines use to open connections. If an outsider knows your wireless access point's code, he can use your network.
The default SSIDs that ship with new hardware are well-known. Changing your wireless access point equipment's default SSID and configuring it not to broadcast the SSID will make your network harder for outsiders to find. On the other hand, many people purposefully leave their wireless networks open so that passers-by can browse the Web on their own notebooks. If you want to take this route, you better be especially careful and configure the security settings on each of your computers to protect your personal data.
33. Go the distance. If a wireless connection is extremely slow or doesn't work at all, it's possible that there's interference or too much distance between you and the hub. Move as close as possible to the wireless hub and try again. Microwaves, cordless phones, and other wireless signals cause interference that can limit Wi-Fi's useful range.
If you have two or more computers, you owe it to yourself to set up a LAN. A network makes transferring information simple and fast, plus it lets your computers share data, devices, and resources. Setting up a network doesn't have to be expensive, either; a few cables and a $20 Ethernet hub is all that's necessary (depending on your needs, of course). Setting up a wireless network will cost more, but this option will give you greater flexibility for using a notebook computer (or PDA) anywhere around your home or office. However you decide to accomplish the job of networking, your computers will be able to help you do so much more once they are no longer individual islands of information.
Reprinted with permission from Smart Computing magazine.