Define "close proximity". You may have too many APs for the area you're trying to cover, depending on how many clients you're trying to serve.
How close (or far) they should be is determined by many factors, including SNR, RSSI, power level of each AP, number of clients attempting to connect per AP, etc. Building design and layout will impact your signal levels (and thus, your AP density) quite a bit. As a frame of reference, I have included my AP breakdown per facility for a handful of facilities, along with the square footage per facility. We're using Cisco 1142 Light-Weight APs, almost pure 802.11n for all of our clients (a few are using 802.11g), and our WLAN is designed to voice specification. Our coverage is phenomenal, and we have almost zero wireless issues. Facility #1, 7 APs, 10,600 sf Facility #2, 5 APs, 6,901 sf Facility #3, 6 APs, 15,300 sf Facility # 4, 8 APs, 14,610 sf (three different sites in one space, makes for a funky design) Facility # 5, 11 APs, 19,877 sf (misleading, because this covers two floors, with a lot of unused space on second floor) Facility # 6, 6 APs, 8,037 sf My experience is roughly 1 AP per 1500 to 2500 sq feet of coverage needed, depending on building design and other considerations. When rough budgeting, I budget for one AP to every 1,000 to 1,200 square feet, because you never know what you're going to run into. In two of our facilities, the building was added on to at some point in the past, so there is a two foot thick mortar, block, brick, and steel wall running through various parts of the office. This one factor significantly increased our costs and altered our design. I don't budget based on users, because my user density is not very high, and I know my users per AP will almost always be 5 or less. A formal site survey will give you much more accurate AP counts for budgeting purposes. Jonathan L. Raper, A+, MCSA, MCSE Technology Coordinator Eagle Physicians & Associates, PA jra...@eaglemds.com www.eaglemds.com -----Original Message----- From: John Hornbuckle [mailto:john.hornbuc...@taylor.k12.fl.us] Sent: Tuesday, October 19, 2010 10:37 AM To: NT System Admin Issues Subject: RE: Update: Group Policy Problems Over Wireless The theory behind auto seems good... Listen for a channel that's not noisy, then use it. But I get what you're saying--there may not be interference on a particular channel when the WAP boots, but that doesn't mean there won't be later. The trouble is that we have 4 WAPs in close proximity. If I should only use those 3 channels, what's my best approach? -----Original Message----- From: Glen Johnson [mailto:gjohn...@vhcc.edu] Sent: Tuesday, October 19, 2010 9:23 AM To: NT System Admin Issues Subject: RE: Update: Group Policy Problems Over Wireless We just had a Cisco site survey done for our wireless and he said "never set them to auto" for the channel. Plot the waps on a map and manually configure the channels to 1 6 or 11 for minimum overlap. IE, waps on the same channel need to be separated to prevent interference. We had previously had ours set to auto and following his advise helped quite a bit. His explanation is that, when configured for auto, the wap listens when it boots and selects the least busy channel. That may be good at boot time but could change significantly later on. Also, if a wap chooses any channel other than 1, 6 or 11, it can cause interference with on other channels. With these 3 channels selected, you get 3 non-overlapping channels. Any other channel will overlap with 2 of the above. ________________________________ From: John Hornbuckle [john.hornbuc...@taylor.k12.fl.us] Sent: Tuesday, October 19, 2010 8:50 AM To: NT System Admin Issues Subject: Update: Group Policy Problems Over Wireless No firm resolution on this yet, but possibly a bit of progress. I kept thinking about the problems we were having in this lab. The computers are the same computers we had in the lab last year, and last year we didn't have these problems. So, what changed? Two things: we replaced the WAPs that serve the lab with newer models, and more WAPs were installed in that area of the building. So I got to thinking that maybe the issue was an incompatibility between Broadcom NICs and the new WAPs, or an issue caused by too many WAPs being in the same vicinity. But we have another lab in a different area of the building that has the exact same WAPs and the exact same computers-but no problems. So that left the latter possibility-lots of WAPs stepping on one another's toes-as the prime culprit. The WAPs are Cisco/Linksys, and they all default to the same channel. I changed the ones in the area that was having the problem to "auto," but that didn't seem to really help. So next I forced the WAPs that serve the lab to "g" rather than "b/g/n." As moment, everything is working fine. My tech and I will be watching throughout the week, and if things are still working after a few days we'll consider the issue resolved. John From: John Hornbuckle [mailto:john.hornbuc...@taylor.k12.fl.us] Subject: Group Policy Problems Over Wireless Short version: Is there a trick to improving group policy processing when accessing the network wirelessly? Long version: We have a lab with machines that have Broadcom wireless NICs in them. Vista OS, connecting to Server 2008 R2 DC. I'm trying to deploy a piece of software to these machines via Group Policy. I have things setup so that if the machine is a member of a certain group, the software is deployed. Unfortunately, it only worked correctly on one of the machines-on all the rest, the software isn't being deployed. So I connect to any of the machines that didn't get the software, and run gpresult. It doesn't show me that those machines are members of the group that gets the software. But I know they are; I've confirmed in ADUC on the DC. They're just not picking up group membership. Looking at the event log for events that happen around startup, I see things that make me think group policy processing is trying to happen prior to the wireless network being initialized. Things like: Event ID 5719 (There are currently no logon servers available to service the logon request.) Event ID 129 (NtpClient was unable to set a domain peer to use as a time source because of discovery error.) Event ID 1129 (The processing of Group Policy failed because of lack of network connectivity to a domain controller.) Connectivity to the DC is fine once you get the [Ctrl] + [Alt] + [Del] window. You can log in (including as someone who has never logged into the machine before), ping the DC, browse to \\domain\syvol<file:///\\domain\syvol>, and so on. It's just that at that point, group policy processing seems to have given up. My machines aren't figuring out that they've been added to a new group. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com<mailto:listmana...@lyris.sunbeltsoftware.com> with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com<mailto:listmana...@lyris.sunbeltsoftware.com> with the body: unsubscribe ntsysadmin NOTICE: Florida has a broad public records law. Most written communications to or from this entity are public records that will be disclosed to the public and the media upon request. 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