Networking / Beginners

Extending the Network with Multiple Hubs

Wired Ethernet hubs and switches come in several sizes with varying number of ports, or jacks, that can be used to connect computers. There are typically 4, 5, 8, 16, 24, or 32 ports. Many of the inexpensive Internet connection sharing routers have a five-port switching hub built in.

If you outgrow your hub, you don't need to completely replace it; you can simply connect a new hub to the old one and gain additional ports. You may also want to add an additional port to help you reduce the amount of network cabling you need: Instead of running long wires from a cluster of computers back to a central hub, you can a small hub near the cluster, and run just one wire back.

When you connect a hub to another hub, rather than to a computer, a special electrical connection is needed; one way or another, the send and receive signals from one hub have to be connected to the receive and send connectors on the other. There are three ways that this can be done:

  • Many hubs have a special socket (port) called an uplink port. A standard UTP Ethernet patch cable can be used to connect an uplink port to a standard port on another hub. If you're using a custom-built cable, use the standard wiring order.
  • Some hubs have one port that can be used either as a standard or uplink port; a switch determines the port's function. To connect this sort of hub to another hub, set the switch to the uplink position and use a standard patch cable or standard wiring order in a custom cable.
  • If the new hub doesn't have an uplink port, you can connect any of its ports to another hub by using a crossover cable, or a custom cable wired in the crossover style.

Also, if you link hub to hub to hub, be careful how you arrange things. To meet Ethernet signaling specifications, there can be at most three hubs between any two computers on the network.

Wireless Networking

Wireless networking adapters come in the same formats as standard Ethernet adapters: internal cards, PC Card (PCMCIA), and standalone boxes with USB attachments. They're installed and configured in the same way as standard Ethernet adapters. Installation was covered in the previous section, and protocol configuration will be covered in the next several sections.

However, wireless adapters require additional configuration for wireless security and wireless network type.

It's assumed that wireless-equipped computers can roam from location to location, and thus can be configured to connect to any of several wireless network groups, each of which may have its own security setup. But, whether you're roaming or not, you need to configure the network's Wired Equivalency Privacy (WEP) security settings.

CAUTION While it's possible to use wireless networking without it, we strongly recommend that you do enable encryption. Without encryption it's possible for neighbors and passers-by to tap into your network without you ever knowing it. At the very least, they can freeload on your Internet connection. At worst, if your network uses Simple File Sharing, random people will be able to access and modify shared files on your network.

If you're configuring your computer to work with an existing network set up by someone else, you just need to obtain the following information in order to get online:

  • SSID (network name), a descriptive text string.
  • If encryption is enabled, you will need a network key (password) that consists of 5 or 13 text characters, or an 8 or 26 digit hexadecimal number, depending on the security level in use. Hexadecimal numbers use the characters 0 through 9 plus A through F.
  • Key index, a number between 1 and 4 (not all networks use this).
  • Authentication mode: Shared Mode or Open System Mode. On corporate networks, you may be provided with additional information needed to configure wireless network authentication settings.
  • Network Type: Infrastructure or ad hoc.

If you're setting up your own network, you'll need to select this information yourself. This is fairly straightforward:

  • SSID (wireless network name)- You can use any short, descriptive text string, such as "Home Network" or "My Company". If you are using access points, you will have to enter the same SSID in each of your access points.
  • Network Key- There are two levels of security currently used by wireless networks, although you'll see four numbers used to describe them: 40- and 64-bit security are actually the same thing, as are 110- and 128-bit security. You should use 110-bit security if all of your equipment supports it; otherwise, use 40-bit. For 110-bit security, choose a 13-character password that includes letters, numbers, and punctuation. For 40-bit security, choose a 5-character password.
  • Authentication Mode- For homemade networks, the authentication mode will always be Open System Mode.
  • Network Type- There are two types of wireless networks: ad hoc and Infrastructure. Infrastructure networks include one or more access points or wireless routers. If you have no access points, you're building an ad-hoc network.

If you're building an Infrastructure network, the first step is to configure the access point(s) according to the manufacturer's instructions. This will make it easier to configure the network adapters; they'll "see" the access points and obtain the SSID automatically.

NOTE If the access point is packaged as part of a router, configure the router at the same time, following the manufacturer's instructions.

If the access point requires an IP address for management purposes, see the discussion "IP Addressing Options" later in this tutorial to help choose an appropriate address.

After you've set up any access points, configure the wireless adapters in each of your computers.

If your wireless adapter is an older one whose drivers don't support Windows's "Wireless Zero Configuration," you'll have to follow the manufacturer's instructions. However, most wireless adapters that are usable with Windows XP can be configured using the standardized setup system supplied with Windows, which I'll describe in the remainder of this section. To configure your wireless adapter, you'll need to log on as a Computer Administrator or Power User. Then, follow these steps:

  1. If a wireless connection icon appears in the notification area, click it. Otherwise, open the Network Connections window from the Start Menu or My Network Places, and open the Wireless Network Connection item.
  2. Available wireless networks will be displayed by their SSID names. Click the Advanced button.
  3. The Wireless Network Connection Properties dialog will appear. (You can also reach this dialog by opening the Properties page for your wireless adapter from Network Connections, and selecting the Wireless Networks tab.)
  4. Select your wireless network (which you can identify by its SSID name) in the top section under Available Networks and click Configure. If you're configuring the first member of an ad-hoc network, there will be nothing to choose from. In this case, click Add, and enter the SSID you wish to use.
  5. In the Wireless Network Properties dialog enter the appropriate security configuration information. If your network was set up by your IT department, enter the setup information they provided. You may need to use the Authentication tab to add additional information supplied by the network manager.

    Otherwise, if you are configuring your own network, follow these steps:
    1. Check Data Encryption (WEP enabled).
    2. Uncheck Network Authentication (Shared mode).
    3. Uncheck The Key is Provided For Me Automatically.
    4. Enter your selected network key twice, under Network Key and under Confirm Network Key.
    5. If you are not using an access point, check This Is a Computer-to-Computer (Ad Hoc) Network. In addition, click the Advanced button and select Computer-to-Computer (Ad Hoc) Networks Only.
  6. Click OK.

If you have an access point or another ad-hoc network member up and running, you can check the wireless connection status by hovering your mouse over the connection icon in the task tray. This will display the current connection speed and signal strength. Double-click the connection to see a graphical display of this same information.

Use the signal strength display to adjust your adapter's antenna to get the best possible reception. Try twiddling the antennae on your access point as well.

NOTE You can change any of the wireless network properties except the Ad Hoc setting when you are logged on using a Power User or Computer Administrator. If you made the wrong choice for Ad Hoc, you'll need to delete the network entry from the Properties dialog and add it again from scratch.

If your computer will be traveling between several wireless networks-for example, between home and the office-or if you visit Internet cafes and business centers with wireless access. Windows will choose whichever network is available as you roam from site to site.

NOTE If you click the Advanced button, you can select which types of networks Windows will make available: Any, Infrastructure Only, or Ad-Hoc Only. If you find that you can't connect to a network that you know to be present in your area, check this setting.

Once your wireless adapters are configured and talking to each other and their access points, if any, you can proceed to configure the network itself.

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