Analysis: Inside Apple’s AirPort Extreme, Time Capsule updates
By Glenn Fleishman
The history of Apple’s AirPort Wi-Fi products is one of fits and starts. The company tends to introduce equipment that’s more advanced than anything offered by any of its competitors, then coast for months or even years without refreshing the line, reaping high margins compared to similar, more advanced devices.
When Apple introduced the revised AirPort Extreme in January 2007, 802.11n devices that could use the 5GHz band were rare enough. Ones that could use either the more common 2.4GHz (which supports the original 802.11b AirPort and 802.11g pre-2007 AirPort Extreme flavors) or the 5GHz band were extremely hard to find and certainly not priced for home users. The AirPort Extreme’s $179 price was low compared to alternatives that tended towards $300.
Two years later, many Wi-Fi routers have simultaneous 2.4/5GHz support, as opposed to a one-or-the-other choice. Cisco’s Linksys WRT610N () didn’t score well on Mac functionality, but performed well in both bands at the same time while costing as little as $30 less than Apple’s base station.
So Tuesday’s change adding the ability to operate on two bands simultaneously is welcome, as it avoids a somewhat complicated alternative if you want to run both 2.4 and 5 GHz networks at once. Before today, you would take a new 802.11n AirPort Extreme or Time Capsule and connect it to your broadband modem. You’d then take another base station, like a pre-2007 AirPort Extreme, set it to bridge mode so it wouldn’t assign out addresses of its own, and plug that into a LAN Ethernet port on the main base station. (I spend a chapter of my book Take Control of Your 802.11n AirPort Network on this topic; I’ll be able to radically revise that chapter in the next edition!)
Now, to run two separate networks, you just turn on the box.
Apple told me in a briefing that you have two choices on how to set up a new dual AirPort Extreme or Time Capsule. If you use its default options, both bands have networks that use the same network name—the name that appears in the AirPort menu.
Normally, Wi-Fi devices choose somewhat arbitrarily which base station they connect to when multiple base stations share the same network name for roaming purposes. Wi-Fi adapters typically try to get the best connection, such as that with the best signal strength, but standard Wi-Fi doesn’t offer better choices.
Apple senior product manager Jai Chulani, who focuses on the company’s Wi-Fi line, said that Apple had modified that for its hardware. He explained that an algorithm looks at the signal strength and also the available network speed to determine which band’s network to join. The 5GHz band works well for higher speeds at short distances, because 5GHz signals don’t pass through walls and ceilings as well as 2.4GHz; 2.4GHz provides greater range. (Older Apple gear and Wi-Fi adapters from other makers work perfectly fine with the revised base stations; they just don’t get this clever advantage.)
You can also choose to set the two bands’ network names differently to force a client to connect to one or the other. This might make sense in a border area, where a client keeps flipping between two networks based on small changes.
Be my guest
The addition of guest networking brings a corporate-level feature into a consumer-level product. In so-called enterprise networks—corporate networks that have deep information technology infrastructures—most Wi-Fi gear is designed to offer up multiple network names, each of which has separate security parameters. One network, for accounting, might require token-based two-factor logins and time-based access. Another, designed for regular employees, might simply use an employee’s standard login and be available all the time.
Apple’s use of this option for guest networking is a nifty twist. A guest network is set up as a separate virtual LAN, in enterprise-speak: a separate but parallel local network that can’t see any of the traffic from the other wireless network, nor any of the Ethernet devices.
As Chulani noted, you might be happy to give visitors Internet access but, “I don’t want to give them access to my entire Wi-Fi network, which includes file servers, and printers,” and so forth. A separate option allows guest users to see each other’s network traffic, so they could share file servers or use Bonjour-based iChat; when disabled, only a cracker running sniffer software would be able to get other guests’ data. Even with a sniffer, the main network’s traffic would remain impenetrable, so long as it was protected with a Wi-Fi encryption method, like WPA2 Personal.
The final improvement brings secure remote hard-drive access to any internal or external base station drive. The system is identical to Back to My Mac, Chulani confirmed, with the exception that only file-sharing is enabled. As with Back to My Mac, a paid MobileMe account is required (not an e-mail-only account, but a regular or family pack user).
That information, entered into a new base station, allows anyone with the same MobileMe credentials entered into a Leopard system to see the base station as another available file server in the Finder’s sidebar in the Shared section.
Back to My Mac uses a host of different protocols to create a well-designed encrypted connection between any two machines that use the same MobileMe account. There’s no word yet whether that feature will appear in firmware upgrades for older base stations, as it’s clearly a software change.
Chulani confirmed that Apple still does not support Time Machine backups to external hard drives attached to an AirPort Extreme Base Station. Drives attached in this fashion first started to appear as an option to Time Machine about a year ago after a firmware upgrade to fix problems with the first Time Capsule release; however, official support has never been forthcoming and many users have had trouble getting consistent backups using this method.
[Glenn Fleishman has written voluminously on AirPort, including the recently revised electronic book Take Control of Your 802.11n AirPort Network (Take Control Books). He writes about Wi-Fi daily at wifinetnews.com.]
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