I started responding to the thread titled "The strategic importance of 802.11a" an quickly got off topic. Frank covered that topic quite well, so I'd like to change the subject from "g" vs. "a" to 2.4GHz vs. 5GHz.
I'd like to discourage the use of 2.4GHz, 802.11n APs. Since we all have to buy new hardware for 802.11n anyway, this is probably our best opportunity to get away from all the limitations of the 2.4GHz band. I believe the best way to avoid migration path issues from "a/g" to "n" will be to roll out 802.11n at 5GHz and retain 802.11g for legacy clients. I'm concerned that because MIMO APs cost more and dual-band APs cost more, dual-band MIMO APs will cost much more. A substantial premium for dual-band, 802.11n APs will lead people to buy single-band devices. If we're counting on "n" to support legacy clients, that band will have to be 2.4GHz. If we get any significant distance down that path, we may be stuck at 2.4GHz until the next technology comes out. I know the standard is being developed around backward compatibility, but that doesn't mean we have to use it. If we can convince vendors that we don't need 802.11n to support legacy clients there's hope for affordable 5GHz 802.11n. I can envision two ways to support legacy clients without using 802.11n. One is to leave our existing 802.11b/g infrastructures in place for legacy clients. I know none of us want to support two infrastructures, but until we replace everything we'll be doing that anyway. We can hope that the advantages of 802.11n will be so great that everybody will upgrade their clients before the roll-out is even completed (yes, I'm being uncharacteristically optimistic). The other is ask manufacturers to provide a relatively cheap 802.11g radio in a 5GHz, 802.11n AP. The obvious drawback to that is paying extra for a radio we hope not to use, but it shouldn't be a tremendous premium. I hope to get lots of feedback on this, even if it's just to tell me I'm nuts. I've been saying for years that the future is at 5GHz, but I fear we're in danger of missing another opportunity to exploit that potential. Chuck Enfield Sr. Communications Engineer Penn State University Telecommunications & Networking Services 110 USB2, UP, PA 16802 Ph. (814) 863-8715 Fx. (814) 865-3988 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
