On Thu, Jan 21, 2010 at 04:18:24PM +0100, Eustace Amah wrote: > One of the problem that am experiencing now is that I configured the > 15 APs with same ESSID, different channels(1,6,11) shared among them > and located all around the school. Remember that the APs are > configured with different subnet from the lease of DHCP server but > when more than 3 XO tries to connect it knocks everyone out > immediately. The APs are PoE enabled. The models are Cisco Small > Business Model WAP4410N. I have increased the power to the APs. > > Any solution to this?
There's not enough problem data above to reduce the possible causes to something workable, but I can suggest data to capture and a way to test for one particular problem. Additional problem data needed: - what does "knocks everyone out immediately" mean? Are other wireless users losing connectivity? Do the XO laptops remain associated (left-hand LED on)? Do the APs remain accessible through their web interface during the symptom? - what does "iwlist eth0 scan" show on an XO laptop? (Start Terminal, become root, type "script scan.log", press enter, type "iwlist eth0 scan", press enter, repeat the scan a few more times, type "exit", send me the scan.log file), Testing for too many APs: - turn off 12 APs leaving three running on different channels; does the symptom still occur? You can skip this test if it is impractical. The purpose of the test is to prevent noise in the commons. - reduce the transmit power on all APs to the minimum value; does the symptom still occur? I've reviewed the WAP4410N product specifications [1]. The XOs will be operating 802.11g, so that is the important thing to look for in the specifications. The WAP4410N has 2 dBi antenna, transmit power of up to 17.5 dBm, and receiver sensitivity of -73 dBm. The specifications suggest it is an indoor unit. Check your environment; make sure the product is not being operated below 0 degrees C, above 40 degrees C, or above 85% humidity. I wasn't able to find what the current firmware version is, because I've no obligation from Cisco. You should check to see if a firmware upgrade is available. References: 1. http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps10047/ps10052/data_sheet_c78-501860.html - > > > -----Original Message----- > From: Martin Langhoff [mailto:[email protected]] > Sent: Thursday, January 21, 2010 1:09 PM > To: James Cameron; [email protected]; Reuben K. Caron; taiwo.alabi; Eustace > Amah; [email protected]; Emeka Lewis Nwankwo; kene.ijezie > Subject: Re: [Server-devel] Technical questions > > On Thu, Jan 21, 2010 at 12:28 PM, Martin Langhoff > <[email protected]> wrote: > > 3 - Define how many users you can connect to an AP -- some APs have > > "configured" hard limits in the software they ship. If you have to > > guess, assume ~40 as the upper limit. > > Let's reword that as: assume 30, which is where most APs start having > problems. If you are using OpenWRT, you can probably support 40. If > you have tested your AP, then you'll know for real. > > In general, it is very hard to go over 40 active nodes per channel; > this is mainly due to limitations of "sharing the commons" of the > radio spectrum. > > High end APs may be able to operate different antennas in different > channels -- so one AP acts as if it were 3, working on 1, 6 and 11. > > cheers, > > > > m > -- > [email protected] > [email protected] -- School Server Architect > - ask interesting questions > - don't get distracted with shiny stuff - working code first > - http://wiki.laptop.org/go/User:Martinlanghoff -- James Cameron http://quozl.linux.org.au/ _______________________________________________ Server-devel mailing list [email protected] http://lists.laptop.org/listinfo/server-devel
