Windows Vista : Build Your Network (part 1) - Terminology Primer, To Wire or Not to Wire

As far as Vista is concerned, your connection to the Internet is no different than your connection to other PCs in your home or office. It's this fact that makes Windows all at once easy to network and frustrating to troubleshoot and secure.

1. Terminology Primer

To start building a network, you should understand a few basic networking concepts:

The distinction between local and remote resources

A local resource is an object—a folder on your hard disk or a printer physically connected to your PC—that's accessible without a network connection. A remote resource is one that resides on another computer to which yours is connected over a network. For example, a web page at http://www.annoyances.org is a remote file, but an HTML file on your own hard disk is a local file, even though they may appear indistinguishable in a browser. Vista tries to blur the line, a strategy that sometimes works and other times causes problems: for instance, different security restrictions and drag-drop rules apply to remote files and folders than to local ones, and the subtlety can be a pain in one's keister.

LAN versus WAN

LAN is shorthand for Local Area Network, a small assemblage of PCs in a home or small office connected with cables or wireless signals. Likewise, WAN stands for Wide Area Network, or a network formed by connecting computers over large distances (e.g., the Internet).

Ethernet

Ethernet is the wired technology upon which the vast majority of local area networks is built. Any PC capable of handling Vista is likely to have a built-in Ethernet adapter (also called a NIC, or Network Interface Card).

A standard Ethernet connection is capable of moving data up to 10 megabits per second (Mbps; see "Bandwidth," later in this list), a Fast Ethernet connection (sometimes marked "10/100") can move data at 100 Mbps, and a Gigabit connection can move data at up to 1000 Mbps.

WiFi

WiFi is a trendy shorthand term for wireless networking based on the 802.11x standards. The early favorite was 802.11b, but with a leisurely maximum speed of only 11 Mbps, it was quickly obsoleted by 802.11g (54 Mbps). Further tweaking has given us multichannel 802.11g and the overhyped 802.11n standards, both of which promise even faster speeds and greater range. Of course, all of these advertised specs assume laboratory-perfect conditions, so unless you're interested in building a vacuum chamber for your wireless equipment, you'll likely get about a third of the quoted speed of your equipment (and less, the poorer the reception gets).

A further caveat is that you need matched equipment to get the best performance: your laptop must have an 'n' radio to get the most out of an 'n' network. Luckily, each of these standards (with the exception of 802.11a) is backward-compatible with earlier incarnations, so an older 'g' laptop will still work on a newer 'n' network, albeit at the slower 'g' speed. Of course, with typical DSL and cable Internet speeds at only 1–3 Mbps, a faster WiFi signal will do nothing to get you your email any faster.

Bluetooth

Bluetooth is a wireless networking "standard" (the term must be used loosely here). Bluetooth will never supplant WiFi, nor is it meant to. Rather, it's an inexpensive, low-power technology and is commonly used in high-end cell phones, handheld PDAs, and some laptops. Most people get their first taste of Bluetooth with wireless cell phone headsets or cordless mice and keyboards, but it does much more than that (at least in theory).

Bandwidth

Bandwidth is the capacity of a network connection to move information (the size of the pipe, so to speak). Bandwidth is measured in Kbps (kilobits per second) for slow connections, Mbps (megabits per second) for faster connections such as DSL, cable, or Ethernet LAN connections, and Gbps (gigabits per second) for the kinds of connections used by huge corporations and Internet providers.

Bandwidth is a shared resource. If a network connection is capable of transferring data at, say, 1.5 Mbps, and two users simultaneously download large files, each will only have roughly 0.75 Mbps (or 768 Kbps) of bandwidth at their disposal.

Ethernet-based local networks can transfer data at up to 1,000 Mbps. High-speed T1, DSL, and cable modem connections typically transfer data up to 1.0 to 6.0 Mbps, while the fastest analog modems communicate at a glacial 56 Kbps, or 0.056 Mbps.

To translate a bandwidth measurement into more practical terms, you'll need to convert bits to bytes. There are 8 bits to a byte, so you can determine the theoretical maximum data transfer rate of a connection by simply dividing by 8. For example, a 384 Kbps connection transfers 384/8 = 48 kilobytes of data per second, which should allow you to transfer a 1 megabyte file in a little more than 20 seconds. However, there is more going on than just data transfer (such as error correction), so actual performance will always be slower than the theoretical maximum.

Protocols

A protocol is the language, so to speak, that your computer uses to communicate with other computers on a network. Now, the days of configuring individual network protocols are long past, having died out with the Windows 95/98 generation. As long as your stuff speaks TCP/IP, it'll work, provided you don't mind occasionally typing in numeric IP addresses.

TCP/IP

TCP/IP is a protocol, or more accurately, a collection of protocols, used in all Internet communications and by most modern LANs. For those of you excited by acronyms, the TCP/IP specification includes TCP (Transmission Control Protocol), IP (Internet Protocol), UDP (User Datagram Protocol), and ICMP (Internet Control Message Protocol).

The amazing thing about TCP/IP, and the reason that it serves as the foundation of every connection to the Internet, is that data is broken up into packets before it's sent on its way. The packets then travel to their destinations independently, possibly arriving in a different order than they were originally sent. The receiving computer then reassembles the packets (in the correct order) back into data.

TCP Ports

TCP/IP data moves in and out of your PC through ports, virtual doors opened by the software that uses your network connection. For example, your email program uses port 25 to send email (using the SMTP protocol) and port 110 to retrieve email (using the POP3 protocol), while your web browser downloads pages through port 80 (using the HTTP protocol).

Windows and some applications typically leave more ports open than you probably need, potentially making your PC vulnerable to spyware, pop ups, viruses, intruders, and other annoyances.

IP addresses

An IP address is a set of four numbers (e.g., 207.46.230.218) that corresponds to a single computer or device on a TCP/IP-based network. Each element of the address can range from 0 to 255, providing 256⁴ or nearly 4.3 billion possible combinations. On the Internet, dedicated machines called domain name servers are used to translate named hosts, such as http://www.microsoft.com, to their respective numerical IP addresses and back again.

No two computers on a single network can have the same IP address, but a single computer can have multiple IP addresses (one for each network to which it's connected).

To connect two different networks to each other, while still maintaining two separate sets of IP addresses, you'll need either a bridge or a router. Provided that you install two network adapters in your PC, Windows can act as an impromptu bridge; just highlight two connections in your Network Connections window , right-click, and select Bridge Connections. A router, of course, is a better choice because it works even if your PC is off, and includes firewall protection to boot.

Firewalls, and why you need one

A firewall can be used to restrict unauthorized access to your system by intruders, close backdoors opened by viruses and other malicious applications, and eliminate wasted bandwidth by blocking certain types of network traffic.

A firewall is a layer of protection that permits or denies network communication based on a predefined set of rules. These rules are typically based on the TCP port through which the data is sent, the IP address from which the data originated, and the IP address to which the data is destined.

The problem is that an improperly configured firewall can cause more problems than it ends up preventing. Windows includes a rudimentary firewall feature, but software-based firewalls simply don't work as well as hardware firewalls like those found in routers.

Switches, access points, and routers

A switch allows you to connect more than two computers together—using cables—to form a local network . (Note that a hub does pretty much the same thing as a switch, but much less efficiently.) Without a hub or switch, the best you could do is connect two computers to each other with a crossover cable.

A wireless access point is essentially a switch (or a hub) for a wireless network, allowing you to connect multiple computers wirelessly. Without an access point, you could only connect two computers wirelessly in "ad hoc" mode (more on that later, too).

Finally, a router is a device that connects two networks, and routes traffic between them. For example, a router can connect a peer-to-peer workgroup to the Internet, allowing you to share a single Internet connection with all the computers in your office. Most routers also double as switches, just as wireless routers double as wireless access points. Plus, any modern router (wireless or otherwise) will have a built-in firewall (typically superior to a software firewall that runs on your computer), so you can basically get everything you need in one inexpensive package.

The good news is that Vista comes with everything you need to take advantage of all of these standards, and use them to access the Internet or share files and devices with other PCs on your network. The bad news is that it's almost never as easy to get it working properly as the industry would lead you to believe.

2. To Wire or Not to Wire

Wiring is a pain, but it works. Wireless is convenient, but flaky. Luckily, you don't have to just stick with one system, nor have it all planned out ahead of time.

For best results, wire your nonmobile desktop system to your router/switch/hub when it's nearby. Cables aren't affected by poor reception, security codes, or interference, and they provide full speed all the time.

Plug one end of an Ethernet cable into your router or DSL/cable modem, and the other end into your PC, and you're done; Vista will set up the connection and get you on the Net in less than two seconds, no questions asked. And unless a small rodent chews its way through said cable, it'll keep working until you unplug it.

If you see a prompt that entices you to Connect to a network, resist the urge if you're using cables; even though it doesn't explicitly say it, the window that appears when you click this link is only for connecting to wireless networks.

Wiring can vary in complexity and cost, depending on your needs, budget, and office layout. (See the upcoming "Cabling Tips" sidebar for additional help.) For example, if you have two or more desktop computers in the same room, wiring is a simple matter of adding a switch and one category-5 patch cable for each machine, as shown in Figure 1. More PCs require a switch with more ports, or possibly multiple switches connected together, and of course, more cables.

Figure 1. An example of a wired peer-to-peer network (LAN) comprised of three computers connected with a switch (or hub); the printer is connected to one of the PCs, which shares it with the others

If you only have two computers, you can eliminate the switch and simply connect them with an inexpensive category-5 crossover cable, as shown in Figure 2. Total cost: $3.99.

Figure 2. A quick and dirty hubless workgroup; given its limitations, however, it's best suited as a temporary solution

Most of the time, it doesn't make sense to use cables to connect a laptop to your network unless its wireless doesn't work. (Of course, if you're using a docking station, plugging in is more practical, but that's up to you.) Wireless, of course, is slicker than using cables, and works anywhere within range of the router; no drilling holes in walls so you can feed cables to all parts of your home or office. Figure 3 shows a typical wireless network with four computers (three PCs and one PDA).

Figure 3. A wireless router acts as both a wireless access point and a switch, allowing you to connect any number of computers—and even WiFi-enabled PDAs—to form a wireless LAN (WiFi antennas are typically internal, and are shown here only for illustrative purposes)

Cabling Tips Within a second or two of connecting both ends of a network cable, the corresponding lights on your hardware should light up. Lights should be visible right on the network adapter, whether it's in the back of your desktop computer or in the side of your laptop. (Note that some devices use multicolor LEDs that appear green if the connection is correct, and red if it's wrong.) Flashing lights usually mean data is being transferred. Connect all your cables while your switch and any other equipment are turned on and while Windows is running. That way, you'll see the corresponding lights go on, indicating that the switch, router, or NIC has detected the new connection. Note that the lights only confirm that the cabling is correct; they won't tell you whether the drivers and protocols are correctly installed. Use only category-5 (Cat-5) patch cables, except for a few very specific situations that require category-5 crossover cables. Use a crossover cable to connect two computers directly (without a hub, switch, or router) or to connect two switches. In some cases where a DSL/cable modem connects directly to a computer with a patch cable, a crossover cable may be required to connect either of these devices to a hub or switch (naturally, consult the documentation to be sure). Either way, if the lights go on, you're using the right kind of cable. When measuring for cables, always add several extra feet to each cable; too long is better than too short. Also, bad cables are not uncommon, so have a few extras around in case any of those lights don't light up. Shop around when looking for cables. Most of the huge mega-computer stores charge too much for cables; you can often find longer, better cables at a fraction of the price (sans the fancy packaging) by shopping at smaller mom-and-pop computer stores. Finally, if your cables are to pass through walls, you may want to install category-5 wall jacks for the tidiest appearance. Note that these accessories can be expensive and cumbersome to wire properly, and are typically unnecessary for all but the most compulsive neat-freaks among us. <Grin>

Wireless needs more setup than cables (if you do it right) and is less reliable than Ethernet. Windows needs at least 5–10 seconds to connect to a previously configured wireless network (more for the first time), and may drop your connection as you move around.

Speed may or may not be a factor in your decision. WiFi is not nearly as fast as wired Ethernet; common 802.11g wireless connections (rated at 54 Mbps) transfer data at about 20–30 Mbps, and this speed drops rapidly as reception worsens. The fastest Ethernet connections move data at 1,000 Mbps (1 Gbps), reception notwithstanding. Of course, the difference is moot if you're only doing Internet (typical broadband is only about 1–3 Mbps), but if you need to transfer files between PCs in your workgroup, wired Ethernet will do it in a fraction of the time.

So, what if you want the convenience of wireless, but the speed and reliability of cables? The short answer is to wait about five years for the technology to improve. The even shorter answer is to simply connect your WiFi-equipped laptop to your network with a cable when your wireless gets cranky or you need to transfer files. Luckily, a properly configured network should have no trouble handling both wired and wireless PCs. Figure 4 shows a common peer-to-peer network setup with two wired desktop computers and a wireless connection to a laptop.

Figure 4. You can mix and match wired and wireless devices with a wireless router; these three computers are on the same network, despite the different means of connection

There's one crucial aspect of wireless networking that simply doesn't exist on a wired network: intruders. By default, most wireless routers have no security features enabled, meaning that any WiFi-enabled computer within range can connect to your workgroup and use your Internet connection.