Tài liệu Wiring the Network docx

Wiring the Network Most people connect their computers using one of two connection systems: Ethernet or Wi-Fi which Apple calls AirPort.. If you connect all of the Macs and Ethernet prin

13.1 Wiring the Network

Most people connect their computers using one of two connection systems: Ethernet or Wi-Fi (which Apple calls AirPort)

13.1.1 Ethernet Networks

These days, every Mac and every network-ready laser printer has an Ethernet jack on the back or side panel (see Figure 13-1) If you connect all of the Macs and Ethernet printers

in your small office to a central Ethernet hub or router —acompact, inexpensive box with jacks for 5, 10, or even more computers and printers —you've got yourself a very fast, very reliable network (Most people wind up hiding the hub in a closet, and running the wiring either along the edges of the room or inside the walls.) You can buy Ethernet cables, plus the hub, at any computer store or, less expensively, from an Internet-based mail-order house (Hubs aren't Mac-specific.)

Tip: If you want to connect only two Macs —say, your laptop and your desktop machine

—you don't need an Ethernet hub Instead, you just need a standard Ethernet cable Run it directly between the Ethernet jacks of the two computers (You don't need a special

crossover Ethernet cable, as you did with Macs of old.) Then connect the Macs as

described in the box on Section 13.1.2.Or don't use Ethernet at all; just use a FireWire cable or a person-to-person AirPort network

Figure 13-1 Every Mac OS X–compatible Mac has an Ethernet jack (left) It looks like an overweight telephone jack It connects to an Ethernet router or hub (right) via an Ethernet cable (also known as Cat 5 or Cat 6), which ends in what looks like

an overweight telephone-wire plug (also known as an RJ-45 connector)

Ethernet is the best networking system for many offices It's fast, easy, and cheap

13.1.2 AirPort Networks

Wi-Fi, known to the geeks as 802.11 and to Apple fans as AirPort, means wireless

networking It's the technology that lets laptops the world over get online at high speed in any Wi-Fi "hot spot." Hot spots are everywhere these days: in homes, offices, coffee shops (notably Starbucks), hotels, airports, and thousands of other places

Tip: At www.jiwire.com, you can type in an address or a city and learn exactly where to

find the closest Wi-Fi hot spots

When you're in a Wi-Fi hot spot, your Mac has a very fast connection to the Internet, as though it's connected to a cable modem or DSL

AirPort circuitry comes preinstalled every Mac laptop, iMac, and Mac Mini, and you can order it built into a new Mac Pro

This circuitry lets your machine connect to your network and the Internet without any wires at all You just have to be within about 150 feet of a base station or (as Windows people call it) access point, which must in turn be physically connected to your network and Internet connection

If you think about it, the AirPort system is a lot like a cordless phone, where the base station is, well, the base station, and the Mac is the handset

The base station can take any of these forms:

• AirPort base station Apple's sleek, white, squarish or rounded base stations ($100

to $180) permit as many as 50 computers to connect simultaneously

UP TO SPEED AirPort a, b, g, and n: Regular or Supersized?

In the short history of wireless networking, Wi-Fi gear has come in several

variants, bearing the absurdly user-hostile names 802.11b, 802.11g, 802.11a,

802.11n, and so on

The difference involves the technical specs of the wireless signal Original

AirPort uses the 802.11b standard; AirPort Extreme uses 802.11g; the current

AirPort cards and base stations use 802.11n

So what's the difference? Equipment bearing the "b" label transfers data through the air at up to 11 megabits per second; the "g" system is almost five times as

fast (54 Mbytes/sec); and "n" is supposed to be four times as fast as that

(Traditionally, geeks measure network speeds in megabits, not megabytes If

you're more familiar with megabytes, though, here's a translation: The older

AirPort gear has a top speed of 1.4 megabytes per second, versus more than 6

megabytes per second for the AirPort Extreme stuff.)

(Oh, and while we're using parentheses here: The only place you'll get the

quoted speeds out of this gear is when you're on the moon Here on earth, signal strength is affected by pesky things like air, furniture, walls, floors, wiring,

phone interference, and antenna angle Speed and signal strength diminish

proportionally as you move away from the base station.)

Now, each successive version of the Wi-Fi base station/laptop circuitry standard

is backward-compatible For example, you can buy a new, 802.11n base station, and still connect to it from your ancient 802.11g PowerBook You won't get any greater speed, of course —that would require a laptop with an 802.11n

transmitter —but you'll enjoy the greater range in your house

It's important to understand, though, that even the most expensive, top-tier cable modem or DSL service delivers Internet information at only about half a

megabyte per second The bottleneck is the Internet connection, not your

network Don't buy newer AirPort gear thinking that you're going to speed up

your email and Web activity

Instead, the speed boost you get with AirPort Extreme is useful only for

transferring files between computers and gadgets on your own network (like the bandwidth-hungry Apple TV) —and playing networkable games

And one more note: All Wi-Fi gear works together, no matter what kind of

computer you have There's no such thing as a "Windows" wireless network or a

"Macintosh" wireless network Macs can use non-Apple base stations, PCs can use AirPort base stations, and so on

•

• The less expensive one, the AirPort Express, is so small that it looks like a small white power adapter It also has a USB jack so you can share a USB printer on the network It can serve up to 10 computers at once

• A wireless broadband router Lots of other companies make less expensive Wi-Fi

base stations, including Linksys (www.linksys.com) and Belkin

(www.belkin.com) You can plug the base station into an Ethernet router or hub, thus permitting 10 or 20 wireless-equipped computers, including Macs, to join an existing Ethernet network without wiring (With all due non-fanboyism, however, Apple's base stations and software are infinitely more polished and satisfying to use.)

Tip: It's perfectly possible to plug a Wi-Fi base station into a regular router, too, to

accommodate both wired and wireless computers

• Another Mac Your Mac can also impersonate an AirPort base station In effect,

the Mac becomes a software-based base station, and you save yourself the cost of

a separate physical base station

A few, proud people still get online by dialing via modem, which is built into some

AirPort base station models The base station is plugged into a phone jack Wireless Macs

in the house can get online by triggering the base station to dial by remote control

Tip: If you connect through a modern router or AirPort base station, you already have a

great firewall pro tecting you You don't have to turn on Mac OS X's firewall

For the easiest AirPort network setup, begin by configuring your Mac so that it can go online the wired way, as described in the previous pages Once it's capable of connecting

to the Internet via wires, you can then use the Airport Utility (in your Applications

Utilities folder) to transmit those Internet settings wirelessly to the base station itself From then on, the base station's modem or Ethernet jack —not your Mac's —will do the connecting to the Internet

GEM IN THE ROUGH Networking Without the Network

In a pinch, you can connect two Macs without any real network at all You can

create an Ethernet connection without a hub or a router —or an AirPort

connection without a Wi-Fi base station

To set up the wired connection, just run a standard Ethernet cable between the

Ethernet jacks of the two Macs (You don't need to use an Ethernet crossover

cable, as you did in days of old.)

To set up a wireless connection, from your menulet, choose Create

Network Make up a name for your little private network, and then click OK On the second Mac, choose Join Network, enter the same private network

name, and click Join

At this point, your two Macs belong to the same ad hoc micro-network But that doesn't mean that you've started accessing their files yet

To do that, in the Finder on one of the Macs, choose Go Connect to Server The Network window opens, showing the icons for all the computers on the

local network Double-click the one you want, enter the account password, if

necessary, and you're in

Whether you've set up your own wireless network or want to hop onto somebody else's, Chapter 18 has the full scoop on joining Wi-Fi networks

13.1.3 FireWire Networks

FireWire networks?

You're forgiven for splurting your coffee Everyone knows that FireWire is great for hooking up a camcorder or a hard drive, and a few people know about FireWire Disk Mode But not many people realize that FireWire makes a fantastic networking cable, since it's insanely, blisteringly fast (All right, gigabit Ethernet is faster, and so is

FireWire 800 But attaining that kind of networking nirvana requires that all your Macs, hubs, and other networking gear are all gigabit-Ethernet or FireWire 800-compatible.)

FireWire networking, technically known as IP over FireWire, is an unheralded, unsung feature of Mac OS X But when you have a lot of data to move between Macs —your desktop and your laptop, for example —a casual FireWire network is the way to go It lets you copy a gigabyte of email, pictures, or video files in a matter of seconds

Here's how you unleash this secret feature:

1 Connect two Macs with a FireWire cable

You can't use the one that fits a camcorder You need a six-pin-to-six-pin cable for traditional FireWire jacks If you want to use the faster FireWire 800 connection

on some of the latest Mac models, you'll need to shop for an even less common cord

In any case, the computers can remain turned on, which is a big difference from FireWire Disk Mode (Section 6.2) (The other difference is that you can continue

to use both Macs while they're connected.)

Figure 13-2 In the Network pane of System Preferences, you can add your FireWire port to the list of network connections The point of this window, by

the way, is that a Mac can maintain simultaneous open network connections—Ethernet, AirPort, FireWire, and dial-up modem (That's a

feature called multihoming.)

2 Open System Preferences Click Network Click the icon and enter your Administrator password Click the + button below the list of network connections The tiny dialog box shown in Figure 13-2 appears, letting you specify what kind

of network connection you want to set up

3 From the pop-up menu, choose FireWire Click Create

Now your newly created FireWire connection appears in the list

4 Repeat steps 2–3 on the second Mac

By now, it may have dawned on you that you can't actually get online via

FireWire, since your cable runs directly between two Macs But you can always turn on Internet Sharing (Section 18.5.4) on the other Mac

5 Quit System Preferences

Your Macs are ready to talk —fast Read the following pages for details on

sharing files between them

Tip: Once you've switched on your FireWire connection, you may need to turn File

Sharing or Internet Sharing off and on again to make it work