Chapter 5. Going Mobile

IN THIS CHAPTER:

40 Connect to the Internet Wirelessly

41 Set Up AirPort to Automatically Reconnect

42 Create a Computer-to-Computer Network

43 Create and Configure a Location

44 Switch to a New Location

Networking takes on a whole new dimension when you unplug the Ethernet cable or phone line and go wireless. Apple's AirPort technology introduced the computing world to the freedom of 802.11 wireless networking back in 1999, and it's become one of the great hits of our time. Wireless-enabled coffee shops , restaurants , bookstores, and other public locales are springing up daily, giving patrons the ability to shed the chains of a stationary, hard-coded Internet configuration. It's all dynamic and automatic now, and the future will only be more so, as sales of laptops (both in the Windows world and among Macs) continue to outstrip sales of even the most powerful desktop computers. Mobility is a much-prized commodity these days.

Wireless networking involves two basic pieces of equipment you have to know about: the AirPort or AirPort Extreme card, and the AirPort Base Station.

Apple's AirPort Base Station ($200) and AirPort Express ($129) are devices that broadcast the wireless network signal to your computer. There might be one (or a compatible device, often referred to as an "access point") installed already at your workplace, or you might choose to buy one in order to set up a home wireless network. It's a fairly complex piece of networking equipment, acting as a wireless hub, media bridge, NAT router, and DHCP server; the details of its operation are beyond the scope of this book and will not be addressed here.

The AirPort card, AirPort Extreme card, and AirPort Extreme or AirPort Express Base Stations make it possible for your Mac to connect to other users without a hard-wired Internet connection.

NOTE

AirPort is Apple's term for 802.11b, currently the most common form of wireless networking. 802.11b can transmit data at up to 11 megabits per second, at a signal range of 50 feet. AirPort Extreme is Apple's implementation of 802.11g, the next -generation standard for wireless networking. 802.11g is backward-compatible with 802.11b (devices using both can share the same network), but it transmits at up to 54 megabits per second. The signal range is the same as that of 802.11b.

Many Mac models come with the AirPort card built-in, but you can install such a card in any Mac, whether a desktop or a laptop. Portable computers (PowerBooks and iBooks) are clearly the ones most likely to benefit from the mobility of AirPort, but stationary desktop computers can reap the rewards tooyou can wire an entire household for Internet access without stringing any Ethernet cables under carpets or over doors.

True, AirPort is somewhat slower than Ethernet, and there's always the issue of signal strength, especially in larger houses ; but because most Internet connectionseven broadbandare nowhere near as fast as AirPort is, in real-world terms you're not going to see the disadvantage . Downloading a web page over AirPort will be just as fast as over Ethernet because the speed bottleneck is in the Internet link itself, not in the LAN. The freedom afforded to you and your computer by AirPort, and the ability to roam freely from home to work to the coffee shop, more than make up for the slight speed penalty wireless networking incurs.

If you have a portable Mac that you frequently take with you from one place to another, chances are that you will often have to switch back and forth between the network configurations that are compatible with each place you go. You might have one set of TCP/IP settings at home, another one at work, and another one at your favorite wireless-enabled coffee shop. It's no fun to have to constantly open up the Network Preferences pane and enter a new set of TCP/IP settings. Mac OS X makes configuring TCP/IP much more direct than Windows does, but it's still not the best use of several minutes of your time when you've just opened up your PowerBook to show someone a cool website.

Fortunately, there's a way to avoid all that tedious configuration: locations . All the TCP/IP configuration that you now know how to do is all part of a "location," which is a configuration profile that applies to a certain network environment. If you have other network environments, each of those can have its own location and its own associated TCP/IP settings. Then, whenever you go from one place to another, you have simply to select which networking location you want to use, and the associated configuration will automatically go into effect.

KEY TERM

Location A set of network configuration settings that you define in association with a certain networking environment, such as your home or work network. Switching from one location to another immediately changes your networking settings.

A location can contain not just TCP/IP settings, but also a profile of which network ports are active. For instance, you might have an Ethernet network at the office, but only AirPort at home; switching from your Work location to your Home location can disable the Ethernet port and enable AirPort. A location can also include VPN settings, as well as a unique preference list for what network devices you do have available.

Of crucial importance to mobile computing is power management. You need to be able to configure your iBook or PowerBook to use its precious battery power efficiently on long airline flights , and yet be able to take advantage of continuous power through a wall adapter if it's plugged in; for example, decreasing the processor speed and letting the display go dim are ways to save power while keeping the computer active. Because configuring your Mac's power-saving behavior is applicable to all Macs, and not just laptops, power management is covered in 125 Choose a Power-Saving Profile .