Apple has added a new article to the Knowledge Base regarding the compatibility of AirPort Extreme networks. Appleis Knowledge Base (sometimes referred to as the KBase) is a central location for all of Appleis support documents and other important information.
When Steve Jobs announced AirPort Extreme at MWSF 2003, he managed to imply that adding a 802.11b (call it Classic AirPort) to a 802.11g network would slow the entire network down to the slower 802.11b speeds. 802.11b offers 11 Mbps in throughput, while 802.11g offers 54 Mbps. TMO has been working on finding out whether or not that was actually the case, but the new KBase article from Apple answers those questions quite nicely, thank you.
According to Apple, when adding 802.11b (Classic AirPort) clients to an 802.11g (AirPort Extreme), each client will get the appropriate data throughput. In other words, AirPort Extreme networks will not be slowed down by the addition of the Classic AirPort card: The 802.11g clients will get a maximum of 54 Mbps, while 802.11b clients will get a maximum 11 Mbps, though Apple specifies only that the Extreme clients will get data at a "higher rate" than the Classic clients. It should also be noted that real-world usage seldom results in these speeds being actually reached. The KBase article also says that all of the various cards and base stations made by Apple and third party vendors should inter-operate, just as they did when it was just 802.11b. From Apple:
Choosing an AirPort card
Because the card slots are different types, AirPort-capable computers use either the AirPort Card or the AirPort Extreme Card. The computeris listed specifications, as at the Apple Store, will name the card used. Computers described as "AirPort Extreme ready" accept the AirPort Extreme Card. Computers labeled as "AirPort ready" accept the AirPort Card. Both cards are available at The Apple Store (http://www.apple.com/store/).
Joining an AirPort Extreme network
Any computer using the earlier AirPort Card can connect to an AirPort Extreme Base Station. Any third-party 802.11b wireless card or adapter that works with an earlier AirPort Base Station should also be able to connect to the AirPort Extreme Base Station.
Joining AirPort and third-party 802.11b networks
Any computer using an AirPort Extreme Card can connect to an earlier AirPort Base Station. The AirPort Extreme Card can connect to the same third-party 802.11b wireless access points that the earlier AirPort Card connects to.
Mixing clients on an AirPort Extreme network
When you mix 802.11b (AirPort) and 802.11g (AirPort Extreme) clients on an AirPort Extreme network, each type of client receives an appropriate data throughput rate. The 802.11g clients continue to receive data at a higher rate than 802.11b clients.
You can find the new Knowledge Base article at Appleis Web site.