Click here to enlarge Originally Posted by glider Click here to enlarge
would be quite surprised by that, my N draft router broadcasts B, G and N (presumably simultaneously in 2.4ghz band)
It's all about frequencies and how they are used. 802.11b and 802.11g are 2.4GHz, 802.11a is 5GHz, and 802.11n uses both frequencies at once, and will allocate channels on the fly as well. Beware "draft N" too - 802.11n took many years to ratify, and most "draft N" equipment doesn't meet the final N spec. (It may not work with "proper" N equipment - although you may find a firmware update will fix that in some cases).

It's also important to realise how the different speeds work - a device using 802.11b talking to a "B and G" router at 5mbit/sec is occupying a potential ~25mbit to an 802.11g device, even though it isn't communicating that fast.

If they want to fix the narrow and/or overlapping channels associated with current technology, or get out of the 2.4GHz frequency space of microwave ovens (which cause a significant slowdown to wireless internet), then compatibility with B and G will have to go.

The next standard (802.11ac) proposes just that - more channels, and bigger channels, occupying more frequency space in the ~5GHz band. I'd say they'd find a way to make it backwards compatible with 802.11n (and possibly 802.11a - not that anyone really has much 802.11a, but still...), but it won't be backwards compatible with 802.11b or 802.11g.

However, given 'n' was something like 5 years in the pipeline before being a ratified standard, I'd say there's plenty of time before you see 802.11ac devices for real. Two years is probably a reasonable estimate. If they turn up marked "draft", avoid - you could be in for big compatibility problems later...