John, I think the only issue is that .11n devices will loose some performance having to share the band with .11g/b devices. Currently we run about a 50-50 split on the 2.4 band between .11n and .11g devices with no particular problems.
-Chris On Aug 24, 2010, at 10:08 AM, "j...@nww.com<mailto:j...@nww.com>" <j...@nww.com<mailto:j...@nww.com>> wrote: Chris, Thanks. Your observation on 40Mhz limiting the channel options in 2.4 band fits with what I've learned also. As I mentioned in my direct reply, your email reminded me -- and I should have thought of this -- that of course the same 3-channel "limitation" exists for 11b/g iPhones. But…what I'm wondering is if the iPhone 4's demand or preference for 11n makes the situation more problematic, especially in a mixed-client environment -- when b/g iPhones are associating to the same 11n access point? Regards, John Cox Senior Editor Network World From: Chris Murphy [mailto:ch...@mit.edu] Sent: Monday, August 23, 2010 7:28 PM To: The EDUCAUSE Wireless Issues Constituent Group Listserv Cc: John Cox Subject: Re: [WIRELESS-LAN] Any issues with iPhone 4 and 2.4GHz 802.11n? John, I don't think there is much of an issue here, unless there is a requirement that the iPhone 4's need the bandwidth possible using 40Mhz channels. Just about every design guideline I've seen, and every conversation I've had with engineers at various networking companies, considers using 40Mhz channels at 2.4Ghz to be a bad idea, due to the loss of what little flexibility one has with channel layout as well as with adverse effects on neighboring networks in crowded areas (the "anti-social" effect), so here at least we never considered it. -Chris On Aug 23, 2010, at 9:12 AM, <<mailto:j...@nww.com>j...@nww.com<mailto:j...@nww.com>> <<mailto:j...@nww.com>j...@nww.com<mailto:j...@nww.com>> wrote: Folks, I was talking to a higher education IT guy last week; they have a lot of iPhones, and are rollling out iPhone 4's to new freshman and to faculty. As part of this, they upgraded the campus WLAN to 802.11n. BUT, after iPhone 4 was announced, they realized its 11n support was ONLY for the 2.4 GHz band (with of course only 3 non-overlapping channels, and tradeoffs if you merge two of them into one 40MHz channel). In SOME locations, they're having to do some fancy juggling of access points, channel and power settings. Juggling 3 channels in a crowded location clearly is NOT new. But the fact that this is occurring in 11n with a popular client device that often relies on WLAN access, seems noteworthy. I was wondering if anyone else is running into similar issues with iPhone 4 and 11n? I'm going to be writing this up as a "Network World" story today or early Tuesday. If you're interested in emailing/talking briefly with me about this, please just copy any listserv response to (or email me directly at) my NW email: <mailto:john_...@nww.com> john_...@nww.com<mailto:john_...@nww.com>. Thanks! Regards, John Cox ______________________________________________________ J o h n C o x Senior Editor Main: 508.766.5301 | Direct: 508.766.5422 Office at home: 978-834-0554 NETWORKWORLD Maximize Your Return on IT 492 Old Connecticut Path | Framingham, MA 01701-9002 ______________________________________________________ NetworkWorld.com<http://www.networkworld.com/> | 2009 Media Guide<http://www.networkworld.com/media/> | Conferences and Events<http://www.networkworld.com/events/> ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at<http://www.educause.edu/groups/>http://www.educause.edu/groups/. =========================================== Chris Murphy Network Engineer MIT Information Services & Technology Room W92-191 77 Massachusetts Avenue Cambridge, MA 02139 <mailto:ch...@mit.edu>ch...@mit.edu<mailto:ch...@mit.edu> ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
