RE: [WIRELESS-LAN] many clients, one room
approach, but it deals with usage and service level issue problem 99.99% of the time. (JON - you might see it differently when you consider having a .11n solution that replaces your wired switches - so, it's not just about organic growth but a paradigm shift in connectivity that matches the shift from desktops to mobile laptops - most would agree that mobile laptops with a wired leash deflates some/most of the value of being a mobile user) Frank From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Jon Freeman Sent: Friday, April 11, 2008 12:52 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] many clients, one room Some math offers insight on this question... Assuming the following: · we're looking at a single area (i.e. lecture hall), · No retransmits are allowed (not real world, but is a best case example) · we're talking about an average sized PPT of 10MB (looking through my PPT folder this was just my average) · Student and teacher expectations of speed is drawn from their homes (i.e. cable and DSL), less than this will be noticed and likely complained about · the room's average data rate is 54Mbs (10 people by 10 people = 50ftx50ft) · 100 people, all downloading at the same time · max radio density for Meru is 3 (i.e. 3 channels of coverage, this is the most non-overlapping channels you can light in this area without interference problems using their latest gear) · Actual throughput for TCP data is 20Mbs per channel (54Mbs less Wi-Fi management overheads - this is a number referred to in the 802.11 spec and one I've observed many times) · Max radio density available from other shipping solutions today is 15 channels Meru Solution: · 20Mbs x 3 = 60Mbs converting to Bytes /8 = 7.5MB/sec /100 people = .075MB/sec (using 1024KB to the MB, this is 76KB/sec/user of TCP!) · Time to download 10MB/.075MB = 133 sec/user to download a 10MB file (about 2 minutes), so a 40MB file would take ~8min/user · Link throughput then is 76KBs TCP for each useryou decide if that's acceptable 14 channel solution: · 20Mbs x 15 = 300Mbs · 5 times the bandwidth = 5 times the throughput · 76KBs/user x 5 = 380KBs TCP for each user of link throughput (and this is a little bit better than most uplink speeds on home broadband, www.speedtest.net http://www.speedtest.net is what I've used on many LANs) · Instead of 2 minutes waiting, the 10MB file downloads with this solution in 26 seconds, and about 1 ½ min for a 40MB file, versus 8 minutes. So, we can assume that Frank's interviews from 2 years ago don't account for the latest technologies. Sorry Frank, I don't mean to poke holes in your study, but it is 2 years old and we are talking about technology. Didn't we stop trying to manage limited bandwidth when ATM failed? When did we go back to thinking that's ok? I like more power, more speed, better, faster Jon 303-808-2666 Xirrus(tm) Array...the Air is the Network(tm)...visit us at www.xirrus.com From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Frank Bulk Sent: Friday, April 11, 2008 10:07 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] many clients, one room Based on research and interviews I performed two years ago, it appeared that for dense client usage in a confined space, Meru was the product most often implemented. These organizations chose Meru because it worked well or better than the competitor. Competitors argued that their product wasn't set up correctly or optimally. I'll let others with production networks pipe in with their experiences. Frank From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Don Wright Sent: Friday, April 11, 2008 9:59 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] many clients, one room I know this has been talked about and debated on this list before, but what are people doing today when faced with a request like the need for 100 students simultaneously downloading a powerpoint presentation. Recently there was discussion on MCA vs. SCA vendors and how each handles this worst case scenario. Since we are an MCA (Aruba), I'd be interested in hearing what others have done or are planning for large classrooms and auditoriums. -- Don Wright Network Technologies Group Brown University wire --- less, wi-fi ))) more ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http
RE: [WIRELESS-LAN] many clients, one room
Some math offers insight on this question... Assuming the following: · we're looking at a single area (i.e. lecture hall), · No retransmits are allowed (not real world, but is a best case example) · we're talking about an average sized PPT of 10MB (looking through my PPT folder this was just my average) · Student and teacher expectations of speed is drawn from their homes (i.e. cable and DSL), less than this will be noticed and likely complained about · the room's average data rate is 54Mbs (10 people by 10 people = 50ftx50ft) · 100 people, all downloading at the same time · max radio density for Meru is 3 (i.e. 3 channels of coverage, this is the most non-overlapping channels you can light in this area without interference problems using their latest gear) · Actual throughput for TCP data is 20Mbs per channel (54Mbs less Wi-Fi management overheads - this is a number referred to in the 802.11 spec and one I've observed many times) · Max radio density available from other shipping solutions today is 15 channels Meru Solution: · 20Mbs x 3 = 60Mbs converting to Bytes /8 = 7.5MB/sec /100 people = .075MB/sec (using 1024KB to the MB, this is 76KB/sec/user of TCP!) · Time to download 10MB/.075MB = 133 sec/user to download a 10MB file (about 2 minutes), so a 40MB file would take ~8min/user · Link throughput then is 76KBs TCP for each useryou decide if that's acceptable 14 channel solution: · 20Mbs x 15 = 300Mbs · 5 times the bandwidth = 5 times the throughput · 76KBs/user x 5 = 380KBs TCP for each user of link throughput (and this is a little bit better than most uplink speeds on home broadband, www.speedtest.net http://www.speedtest.net is what I've used on many LANs) · Instead of 2 minutes waiting, the 10MB file downloads with this solution in 26 seconds, and about 1 ½ min for a 40MB file, versus 8 minutes. So, we can assume that Frank's interviews from 2 years ago don't account for the latest technologies. Sorry Frank, I don't mean to poke holes in your study, but it is 2 years old and we are talking about technology. Didn't we stop trying to manage limited bandwidth when ATM failed? When did we go back to thinking that's ok? I like more power, more speed, better, faster Jon 303-808-2666 Xirrus(tm) Array...the Air is the Network(tm)...visit us at www.xirrus.com From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Frank Bulk Sent: Friday, April 11, 2008 10:07 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] many clients, one room Based on research and interviews I performed two years ago, it appeared that for dense client usage in a confined space, Meru was the product most often implemented. These organizations chose Meru because it worked well or better than the competitor. Competitors argued that their product wasn't set up correctly or optimally. I'll let others with production networks pipe in with their experiences. Frank From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Don Wright Sent: Friday, April 11, 2008 9:59 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] many clients, one room I know this has been talked about and debated on this list before, but what are people doing today when faced with a request like the need for 100 students simultaneously downloading a powerpoint presentation. Recently there was discussion on MCA vs. SCA vendors and how each handles this worst case scenario. Since we are an MCA (Aruba), I'd be interested in hearing what others have done or are planning for large classrooms and auditoriums. -- Don Wright Network Technologies Group Brown University wire --- less, wi-fi ))) more ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] many clients, one room
Load balancing is there. There's a trick to making it work but it does (trick as in tricking the client to connect to less used channel/radio) - and, no breakage to the 802.11 spec at all i.e. fully compliant and certified. Jon 303-808-2666 Xirrus(tm) Array...the Air is the Network(tm)...visit us at www.xirrus.com -Original Message- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Wilson Dillaway Sent: Friday, April 11, 2008 11:56 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] many clients, one room Jon, Given that the clients make all the decisions, how can we assure, given 14 channels, that the users will equally balance themselves across all 14, rather than bunching up? Wilson Jon Freeman wrote: Some math offers insight on this question... Assuming the following: · we're looking at a single area (i.e. lecture hall), · No retransmits are allowed (not real world, but is a best case example) · we're talking about an average sized PPT of 10MB (looking through my PPT folder this was just my average) · Student and teacher expectations of speed is drawn from their homes (i.e. cable and DSL), less than this will be noticed and likely complained about · the room's average data rate is 54Mbs (10 people by 10 people = 50ftx50ft) · 100 people, all downloading at the same time · max radio density for Meru is 3 (i.e. 3 channels of coverage, this is the most non-overlapping channels you can light in this area without interference problems using their latest gear) · Actual throughput for TCP data is 20Mbs per channel (54Mbs less Wi-Fi management overheads - this is a number referred to in the 802.11 spec and one I've observed many times) · Max radio density available from other shipping solutions today is 15 channels _Meru Solution:_ · 20Mbs x 3 = 60Mbs converting to Bytes /8 = 7.5MB/sec /100 people = .075MB/sec (using 1024KB to the MB, this is 76KB/sec/user of TCP!) · Time to download 10MB/.075MB = 133 sec/user to download a 10MB file (_about 2 minutes_), so a 40MB file would take ~8min/user · Link throughput then is 76KBs TCP for each useryou decide if that's acceptable _14 channel solution:_ · 20Mbs x 15 = 300Mbs · 5 times the bandwidth = 5 times the throughput · 76KBs/user x 5 = 380KBs TCP for each user of link throughput (and this is a little bit better than most uplink speeds on home broadband, www.speedtest.net http://www.speedtest.net is what I've used on many LANs) · Instead of 2 minutes waiting, the 10MB file downloads with this solution in _26 seconds_, and about 1 ½ min for a 40MB file, versus 8 minutes. So, we can assume that Frank's interviews from 2 years ago don't account for the latest technologies. Sorry Frank, I don't mean to poke holes in your study, but it is 2 years old and we are talking about technology. Didn't we stop trying to manage limited bandwidth when ATM failed? When did we go back to thinking that's ok? I like more power, more speed, better, faster Jon 303-808-2666 *Xirrus**(tm)** Array...the**/ Air/** **is the Network(tm)...visit us at www.xirrus.com*** *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] *On Behalf Of *Frank Bulk *Sent:* Friday, April 11, 2008 10:07 AM *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU *Subject:* Re: [WIRELESS-LAN] many clients, one room Based on research and interviews I performed two years ago, it appeared that for dense client usage in a confined space, Meru was the product most often implemented. These organizations chose Meru because it worked well or better than the competitor. Competitors argued that their product wasn't set up correctly or optimally. I'll let others with production networks pipe in with their experiences. Frank *From:* The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] *On Behalf Of *Don Wright *Sent:* Friday, April 11, 2008 9:59 AM *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU *Subject:* [WIRELESS-LAN] many clients, one room I know this has been talked about and debated on this list before, but what are people doing today when faced with a request like the need for 100 students simultaneously downloading a powerpoint presentation. Recently there was discussion on MCA vs. SCA vendors and how each handles this worst case scenario. Since we are an MCA (Aruba), I'd be interested in hearing what others have done or are planning for large classrooms and auditoriums. -- Don Wright Network Technologies Group Brown University wire --- less, wi-fi
RE: [WIRELESS-LAN] Mac issues
It was part of the MAC OS update. Jon 303-808-2666 ...THE ONLY TRUE WIRELESS SWITCH...the Air is the Network... This electronic message transmission contains information from the Company that may be proprietary, confidential and/or privileged. The information is intended only for the use of the individual(s) or entity named above. If you are not the intended recipient, be aware that any disclosure, copying or distribution or use of the contents of this information is prohibited. If you have received this electronic transmission in error, please notify the sender immediately by replying to the address listed in the From: field. From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Angela K Hollman Sent: Wednesday, March 05, 2008 1:40 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Mac issues Was this wireless driver update delivered as part of a Mac OS Update? Or do you have to go to the Mac site to get the update? _ Angela K. Hollman Information Technology Services Network Analyst (308)865-8176 Jon Freeman [EMAIL PROTECTED] Sent by: The EDUCAUSE Wireless Issues Constituent Group Listserv WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU 03/05/2008 09:46 AM Please respond to The EDUCAUSE Wireless Issues Constituent Group Listserv WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU To WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU cc Subject Re: [WIRELESS-LAN] Mac issues There is currently no way to change the preferred band with the Apple supplicant (at the client end - although you can play tricks at the BSS to force them onto .11a). Although, there is one old software package that can do it on older systems (not likely this is of any help and isn't a free option). The supplicant scans both frequencies, looking for the best SNR characteristics. Your experience isn't unusual as most .11a APs don't provide a hot enough signal to beat the .11bg SNR offered. In most of our companies implementation we see the opposite, but is likely due to our higher RSSI on .11a channels than seen in most all legacy implementations. Not surprising as we use a high gain antenna. Not a sales pitch here - just wanted to point out that different infrastructures will produce different behaviors. Any survey software should allow you to see the SNR characteristics for your area - this should give you a hint of what's going on with the supplicants on your notebooks. On 2/12 Apple delivered an update to Leopard 10.5's wireless drivers. After the update you should see the revs below. 1.Atheros - Wireless Card Firmware Update should be at: 1.3.2 2.Broadcom - Wireless Card Firmware Update should be at: Broadcom BCM43XX 1.0 (4.170.46.3) 3.Intel - Didn't have one at the time of this writing. You might want to try this update as the drivers solve some issues they had with MAC clients slowing their connection speeds over time and not moving to higher speeds as conditions improved. You may also find this changes your supplicant's behavior. Jon 303-808-2666 ...THE ONLY TRUE WIRELESS SWITCH...the Air is the Network... This electronic message transmission contains information from the Company that may be proprietary, confidential and/or privileged. The information is intended only for the use of the individual(s) or entity named above. If you are not the intended recipient, be aware that any disclosure, copying or distribution or use of the contents of this information is prohibited. If you have received this electronic transmission in error, please notify the sender immediately by replying to the address listed in the From: field. From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of David Wang @ UoG CCS Sent: Tuesday, February 26, 2008 8:32 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Mac issues I am new to Mac. Anyone by chance knows Leopard on MacBook or Pro (with 802.11a/b/g/n card) wireless preference: does it try a/n first? or b/g/n first? and is there any way to change it? thanks in advance. We have 802.11a and b/g available with same SSID, and find Leopards only connecting to b/g, not a. David Wang, Networking Services,CCS www.uoguelph.ca http://www.uoguelph.ca/ 519-824-4120 x52046 Jon Freeman wrote: Fyi - the APs require a fix as well, only Apple Airports and one other AP vendor have made the ESS fixes that I am aware of. Regards, Jon 303-808-2666 -Original Message- From: Lee H Badman [mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] ] Sent: Tuesday, February 19, 2008 10:48 AM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:Re: [WIRELESS-LAN] Mac issues Thanks, Phil. I knew 10.5.2 was coming, just didn't realize it was actually here. It is frustrating that something
RE: Re: [WIRELESS-LAN] Using 4 channels rather then 3 for the 2.4ghz wifi
FYI - this configuration does not conform to the 802.11 specifications. Regards, Jon 303-808-2666 -Original Message- From: Philippe Hanset [mailto:[EMAIL PROTECTED] Sent: Thursday, February 21, 2008 12:43 PM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:Re: [WIRELESS-LAN] Using 4 channels rather then 3 for the 2.4ghz wifi Nick, We have been doing 1-4-7-11 (but 1-4-8-11 makes more sense) since 2000 and even with 802.11g we still like it. The loss that you get from overlapping is largely regained by having a 4th channel. Other sources advise to play with smaller cell and reducing the milliwatts emitted from the AP instead of using 4 channels! CIROND published a paper about the usage of 4 channels as well, (search for CIROND, 4 channels, 802.11b...) warning that though it is acceptable with CCK, it might create problems with OFDM! Philippe -- Philippe Hanset University of Tennessee, Knoxville Office of Information Technology Network Services 108 James D Hoskins Library 1400 Cumberland Ave Knoxville, TN 37996 Tel: 1-865-9746555 -- On Thu, 21 Feb 2008, Urrea, Nick wrote: We have a large study room at UC Hastings which accommodates up to 150 students. On average I see about 80-100 users using the wifi in the room. To load balance the wifi in the room I have setup 4 APs. Right now we use the 3 non-overlapping 2.4ghz channels, 1, 6, and 11. The 4 APs are line of sight with each. Do you think it would be a good idea to go to 4 channels instead 3 Ex: (1, 4, 8, 11) Nicholas Urrea Information Technology UC Hastings College of the Law [EMAIL PROTECTED] x4718 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: Re: [WIRELESS-LAN] Mac issues
Fyi - the APs require a fix as well, only Apple Airports and one other AP vendor have made the ESS fixes that I am aware of. Regards, Jon 303-808-2666 -Original Message- From: Lee H Badman [mailto:[EMAIL PROTECTED] Sent: Tuesday, February 19, 2008 10:48 AM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:Re: [WIRELESS-LAN] Mac issues Thanks, Phil. I knew 10.5.2 was coming, just didn't realize it was actually here. It is frustrating that something that's 190 MB in size (the 10.5.2 patch) has so little real information available on it. I dig around on several Mac forums to no avail, and find Apple's site to be almost worthless in this respect- does anyone know where any real detail on Mac updates might be available? Also- am seeing just as many trouble reports as fixes attributed to 10.5.2 during random searches- hopefully it really does help and not set us back even further. Lee From: Phil Trivilino [mailto:[EMAIL PROTECTED] Sent: Tuesday, February 19, 2008 1:04 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Mac issues Lee We have seen lots of failure to authenticate to our Cisco LWAPP system on startup by MAC OSX 10.5 - the recent release of 10.5.2 seems to have fixed that. Other MAC users across campus report improvements in wireless functionality on their Macs since the update. Sorry I do not have more specific information. Phil From: Lee H Badman [mailto:[EMAIL PROTECTED] Sent: Tuesday, February 19, 2008 12:14 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Mac issues There is a known condition with wireless Macs where the adapter clings to bad 11a cells, even when better 11g is available- we are struggling a bit with this in certain spots right now. I'm also getting a sense that the newer Mac laptops (both MacBookPro and Air) that have 11n built in may be somewhat dodgy on our Cisco LWAPP network, though so far the evidence is circumstantial at best. Is anyone else seeing Mac-specific wireless issues? Regards- Lee Lee H. Badman Wireless/Network Engineer Information Technology and Services Syracuse University 315 443-3003 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] Classroom wireless WAP counts
Peter - Packet limiting per station/second, but this is backed up with .11e, /p, and /Q functional support. At a higher level, packet limits per SSID are also used to ensure different classes of user are serviced with different levels of resource. The configuration of these options is based on environmental factors such as stations density, application requirements (data, voice, video), and wired network capabilities deployed. Ultimately, the best solution is no hub type sharing. We've implemented several wireless substitution networks (replacing wired) with the high radio count arrays (16) using small cell, sharp cell, and load balancing. This configuration allows you to use wireless like you do with a switch today. One architectural firm doing this just wanted to eliminate the mess of structured cabling in a new facility - the higher value they're realizing from this is the mobile productivity gains not anticipate from having most all of their users un-tethered (a few users are still tied due to the higher processing and giant file size requirements of AutoCAD - they expect 300Mbs .11n channels to solve the wire problem with them shortly) Jon From: Peter Redhead [mailto:[EMAIL PROTECTED] Sent: Friday, December 14, 2007 10:53 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Classroom wireless WAP counts Hi Jon, How do you manage traffic shaping at the edge? Thanks Jon Freeman [EMAIL PROTECTED] 12/14/2007 12:45 PM Tim, We look at this problem from two perspectives - 1) reducing the number of drops, 2) ensuring maximum capacity per client. The calculation you're looking at is fairly straightforward - Mbs per user desired = 20Mbs (TCP per channel) / number of users. 20Mbs is used since this is the typical data carrying capacity of 11g/11a per channel with good signal quality and normal SNR measures. If you want users to have a similar experience to what they have at home (this is a typical user's expectation), you would try to provide about 1Mbs per user to match DSL/Cable type BB connections. This amounts to 20 users per radio. If you're looking to substitute wireless for wired connections, you'd want to provide something 5Mbs. Also, in any case, you want traffic shaping at the edge to ensure the first TCP connected client doesn't gain an unfair advantage..this is due to the TCP characteristic on a shared connection to use all available bandwidth. Shaping would limit the bandwidth on a packets per second basis per station which fixes the issue and allows a fair use of the shared bandwidth. In K12 situations with laptop carts, we've accomplished this with multiple radios (separate non-overlapping channels) provided in every space - allows for multiple laptop carts to be used in adjacent rooms served by a single 4 radio Array (with load balancing capability). In fact, this is the only way to serve high density deployments - the best example here is the ITU (International Telecommunications Union) which sits almost 2000 users in one room. We user 4 Arrays with 15 radios each for a total of 1.2Gbs of TCP Wi-Fi capacity. Hope this helps. Regards, Jon Freeman 303-808-2666 Xirrus, Inc. From: Gruenhagen, Timothy T. Mr. [mailto:[EMAIL PROTECTED] Sent: Friday, December 14, 2007 10:14 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Classroom wireless WAP counts I am working to develop a rule of thumb number of seats per classroom WAP for our institution. I realize that it is a highly variable ratio depending on what type of applications are being run, size of room, etc. I'm considering 1 WAP per 25- 50 seats. Does anyone have a number they use for a starting point? Thanks, Tim Gruenhagen Manager of Network Engineering Miami University Oxford Ohio ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] Classroom wireless WAP counts
Tim, We look at this problem from two perspectives - 1) reducing the number of drops, 2) ensuring maximum capacity per client. The calculation you're looking at is fairly straightforward - Mbs per user desired = 20Mbs (TCP per channel) / number of users. 20Mbs is used since this is the typical data carrying capacity of 11g/11a per channel with good signal quality and normal SNR measures. If you want users to have a similar experience to what they have at home (this is a typical user's expectation), you would try to provide about 1Mbs per user to match DSL/Cable type BB connections. This amounts to 20 users per radio. If you're looking to substitute wireless for wired connections, you'd want to provide something 5Mbs. Also, in any case, you want traffic shaping at the edge to ensure the first TCP connected client doesn't gain an unfair advantagethis is due to the TCP characteristic on a shared connection to use all available bandwidth. Shaping would limit the bandwidth on a packets per second basis per station which fixes the issue and allows a fair use of the shared bandwidth. In K12 situations with laptop carts, we've accomplished this with multiple radios (separate non-overlapping channels) provided in every space - allows for multiple laptop carts to be used in adjacent rooms served by a single 4 radio Array (with load balancing capability). In fact, this is the only way to serve high density deployments - the best example here is the ITU (International Telecommunications Union) which sits almost 2000 users in one room. We user 4 Arrays with 15 radios each for a total of 1.2Gbs of TCP Wi-Fi capacity. Hope this helps... Regards, Jon Freeman 303-808-2666 Xirrus, Inc. From: Gruenhagen, Timothy T. Mr. [mailto:[EMAIL PROTECTED] Sent: Friday, December 14, 2007 10:14 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Classroom wireless WAP counts I am working to develop a rule of thumb number of seats per classroom WAP for our institution. I realize that it is a highly variable ratio depending on what type of applications are being run, size of room, etc. I'm considering 1 WAP per 25- 50 seats. Does anyone have a number they use for a starting point? Thanks, Tim Gruenhagen Manager of Network Engineering Miami University Oxford Ohio ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] Wi-Spy device: Spectrum Analyzer
I have both of these tools - the WiSpy device and software are good for seeing the RF conditions (layer 1) but don't show things at higher OSI layers as Airmagnet does. Also it's only good for 2.4Ghz for now, but they have a 5Ghz on the roadmap. Regards, Jon 303-808-2666 -Original Message- From: Shari Kimlinger [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 05, 2007 01:06 PM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:[WIRELESS-LAN] Wi-Spy device: Spectrum Analyzer We are looking for a spectrum analyzer. We have read that Airmagnet is a good solution. We are curious if anyone has experience with the less expensive USB Wi-Spy device? Thanks in advance, much appreciated. Shari Kimlinger Central Piedmont Community College Charlotte NC ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] 802.11n tied to 802.3at
None that I'm aware of - the only one of particular concern (and only in Europe), is the 5.470-5.725 band since it's required there to run .11h to ensure no interference with their aircraft radar systems. Frankly, the only place you'd see this is in an airport in Europe and the only device that needs to worry about it are AP and Stations in use at those locations. We have yet to see a instance in Europe that has had this issue. As higher level standards in 802.11 call for more AP control, this will become more valuable in ensuring less co-channel interference across heterogeneous environments. But, it will also mean less need for IT intervention as the access device will make these complex decisions themselves - thus removing needs for high level RF expertise. Regards, Jon -Original Message- From: Frank Bulk - iNAME [mailto:[EMAIL PROTECTED] Sent: Monday, November 19, 2007 5:49 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11n tied to 802.3at Do any of the bands have lesser/no DFS requirements? If so, those are will be more attractive. Frank -Original Message- From: Jon Freeman [mailto:[EMAIL PROTECTED] Sent: Monday, November 19, 2007 6:32 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11n tied to 802.3at The most used indoor bands will likely be the two lower bands (5.150-5.250 and 5.250-5.350 which have power in the 40mW and 200mW levels respectively), the two upper bands will likely be used more frequently outdoors (due to their higher upper power level limits of 1000mW and 800mW). There are other factors such as station supplicant/radio support for the added bands (newer devices should support all of them - but they're new so you should double check). Still, some of the upper bands might be used indoors in higher capacity applications. And who doesn't want more capacity? Jon -Original Message- From: Dale W. Carder [mailto:[EMAIL PROTECTED] Sent: Sunday, November 18, 2007 9:10 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11n tied to 802.3at On Nov 18, 2007, at 7:06 PM, Kevin Miller wrote: One thing to note is that 300Mbps as a symbol rate is only possible with 40MHz channels (versus the 20MHz standard width for 802.11a/b/ g) .. which in 2.4GHz takes you from 3 non-overlapping to 1 non- overlapping. In 5GHz you have at least 8 40MHz non-overlapping channels. Likewise, does anyone have a feel for which bands within 5GHz will be commonly used indoors? Dale ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] 802.11n Draft 2.0
We supplied wi-fi to Interop this year where 60% of all clients connecting were 11a. We're seeing the same stats at the ITU in Geneva during the world radio congress last month. Del'Oro indicated the majority shipping of tri-mode or 11a stations occured in June of 06. Regards, Jon 303-808-2666 -Original Message- From: Frank Bulk [mailto:[EMAIL PROTECTED] Sent: Tuesday, November 13, 2007 06:05 PM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:Re: [WIRELESS-LAN] 802.11n Draft 2.0 For those organizations that are risk-averse and/or price conscious, the best choice may be deploying 802.11b/g everywhere now (in positions where an 802.11n AP could be dropped in later) and then upgrading to 802.11n in 2-3 years. This best applies to those who have no wireless today. If you're wondering why I skipped dual-radio/dual-mode APs that support 802.11a, it's because it's going to add $100+ per AP. Yes, 802.11a is growing, but it's predominately an 802.11b/g client world today upgrading to dual-band 802.11n. Frank -Original Message- From: Philippe Hanset [mailto:[EMAIL PROTECTED] Sent: Tuesday, November 13, 2007 4:58 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11n Draft 2.0 Lee, It's all about be willing to pay the price of being an early adopter! Is it better to deploy an early 802.11n today and deal with the consequences (two cat5, two 802.3af ports, I wonder if you can etherchannel two 100 Mbps ports for each AP since you bring two cat5 anyway!) or wait for a later 802.11n with 802.3at for power (one cable) and by that time change your HP procurve 10/100 to Gig Switches anyway! Meanwhile deploy a cheap 802.11g infrastructure. In our case we still deploy 802.11g networks, while waiting for n and at to settle down (we will have n in a few advanced building as pilots) In a world where people downgrade OSes to the previous one, I wouldn't worry too much about being bleeding edge ;-) Philippe Hanset University of Tennessee -- On Tue, 13 Nov 2007, Lee Weers wrote: We are looking at a campus wide wireless deployment, and my supervisor is pushing for a complete Cisco 1252 with N draft 2.0 capability. We would have about a total of 250 to 300 AP's in full deployment. Our wired infrastructure is currently 100% Procurve with about 90% of it being 10/100 switched. I'd like to know what other schools are doing with 802.11n. Thank you, Lee Weers Assistant Director for Network Services Central College IT Services (641) 628-7675 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN]
What tool are you using for power? This is important since you could be seeing data from probe requests ACKs coming from the AP (as in a site planner tool like airopeek, Airmagnet, etc) or raw RF data as seen in a Spectrum Analyzer (oscilloscope, Wi-Spy, or the ones built into all our arrays). Without any power reporting standards in the existing 802.11 spec, vendors have leeway in how they respond to probe requests that report power in ACKs resulting in many unusual reading for some known and some unknown reasons. None of this breaks the standard. Personally, I suspect it's your AP's playing tricks with their ACKs reported power levels. Could be they want STAs to connect to the better secured SSID - since STAs might have previously connected to the PSK net, they will want to again if they see a higher power level. The AP tries to trick them into picking the more secure SSID. It's not likely you'll get anyone to admit this though - they wouldn't share this with anyone outside of engineering. Is there a specific problem you're having as a result of this observation? Regards, Jon 303-808-2666 From: Matt Ashfield [mailto:[EMAIL PROTECTED] Sent: Thursday, October 18, 2007 5:39 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] I've been seeing this problem as well. Has anyone found a solution to it? We are using Nortel/Trapeze gear. Our WPA/TKIP/802.1x ssid is more powerful than our WPA-PSK ssid even though theyre coming from the same radio with the same power setting?! Any advice is appreciated. Matt [EMAIL PROTECTED] From: Lee H Badman [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 02, 2007 12:23 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] I completely agree on your summation of Windows, and it's flaky bars. But as Peter (Queensland University) mentions, it becomes more puzzling when tools like AirMagnet seem to back up the phenomenon. Lee H. Badman Wireless/Network Engineer Information Technology and Services Syracuse University 315 443-3003 From: Emerson Parker [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 02, 2007 10:47 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] As far as Windows is concerned, it does an average of the signal levels it sees. The problem is that Windows doesn't scan often enough or long enough to actually see the beacon and sometimes records a zero measurement. Multiple readings of zero results in a lower average and the false impression of widely fluctuating signal levels. . If not windows, it could be as simple as the AP alternating antennas for the beacon and the position of the clients can't see the second antenna as well as the first. -Emerson From: Peter Arbouin [mailto:[EMAIL PROTECTED] Sent: Monday, October 01, 2007 11:59 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Hi, We have also seen this when looking into problem areas using Airmagnet Laptop analyzer the signal strength from the same ap on different ssids fluctuates, usually with the open ssid having stronger signal strength. Not sure why, but we would also be interested to hear if there is a reason. Regards, Peter. Peter Arbouin Network Engineer Network Operations Centre, ITS Queensland University of Technology Brisbane, QLD, Australia PH: (07) 313 81030 From: Lee H Badman [mailto:[EMAIL PROTECTED] Sent: Tuesday, 2 October 2007 6:16 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Just now starting to poke at this- we have an open-auth network and an 802.1x network. In areas where we are more hot-spotty and a client can only see a single AP, we're getting a fair number of reports that the 802.1x network is weaker in signal out of the same LWAPP Cisco AP than the open WLAN SSID is. My first thought is that it's likely in the way that RSSI/bars are displayed on individual clients, but we're also hearing that the 802.1x network in these spots was too weak to use, but when jumping over to the open network, the connection was usable. Has anyone else had to deal with this perception? Mostly this seems to be a Mac issue, but not exclusively. Again- haven't done much real testing, but are hearing it enough where I wonder if others have seen similar. Lee H. Badman Wireless/Network Engineer Information Technology and Services Syracuse University 315 443-3003 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this
Re: [WIRELESS-LAN]
Increasing the beacon rate is a tempting solution but is typically not a good idea due to the cost in term of spectrum use for this management protocol. Regards, Jon 303-808-2666 -Original Message- From: Emerson Parker [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 02, 2007 07:47 AM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:Re: [WIRELESS-LAN] As far as Windows is concerned, it does an average of the signal levels it sees. The problem is that Windows doesn't scan often enough or long enough to actually see the beacon and sometimes records a zero measurement. Multiple readings of zero results in a lower average and the false impression of widely fluctuating signal levels. . If not windows, it could be as simple as the AP alternating antennas for the beacon and the position of the clients can't see the second antenna as well as the first. -Emerson From: Peter Arbouin [mailto:[EMAIL PROTECTED] Sent: Monday, October 01, 2007 11:59 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Hi, We have also seen this when looking into problem areas using Airmagnet Laptop analyzer the signal strength from the same ap on different ssids fluctuates, usually with the open ssid having stronger signal strength. Not sure why, but we would also be interested to hear if there is a reason. Regards, Peter. Peter Arbouin Network Engineer Network Operations Centre, ITS Queensland University of Technology Brisbane, QLD, Australia PH: (07) 313 81030 From: Lee H Badman [mailto:[EMAIL PROTECTED] Sent: Tuesday, 2 October 2007 6:16 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Just now starting to poke at this- we have an open-auth network and an 802.1x network. In areas where we are more hot-spotty and a client can only see a single AP, we're getting a fair number of reports that the 802.1x network is weaker in signal out of the same LWAPP Cisco AP than the open WLAN SSID is. My first thought is that it's likely in the way that RSSI/bars are displayed on individual clients, but we're also hearing that the 802.1x network in these spots was too weak to use, but when jumping over to the open network, the connection was usable. Has anyone else had to deal with this perception? Mostly this seems to be a Mac issue, but not exclusively. Again- haven't done much real testing, but are hearing it enough where I wonder if others have seen similar. Lee H. Badman Wireless/Network Engineer Information Technology and Services Syracuse University 315 443-3003 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] Outdoor Antenna
If you describe the application it would help to answer some of your questions. Regards, Jon 303-808-2666 -Original Message- From: Allen Matthews [mailto:[EMAIL PROTECTED] Sent: Wednesday, September 05, 2007 11:20 AM Pacific Standard Time To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject:[WIRELESS-LAN] Outdoor Antenna I am working to set up outdoor antenna for Wi-FI.. We are using Cisco 4404 and LWAPP Access point. Can anyone help me with this? Who do you order equipments to support AP from? (I have seen Cisco LWAPP package) Distance problem? Should AP be place on 2 story or 1 story building? What kind of antenna do you recommend? Dipole? Omni? or Patch Panel? Any information will be helpful.. If you have picture of your outdoor antenna, can I see it? Thanks.. -- --- Allen Matthews Network Engineer Gallaudet University Information Technology Services Washington, DC ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] Cisco LWAPP, multicast/peer to peer blocking modes
Multicast can be tamed if you have a system that supports multicast pruning (a non-required extension to that protocol) which limits the distribution to stations that subscribe to the stream. Check with your vendor to see if it's supported. If it is, you should find it easily turned on through a WMI/CLI switch. Station to station blocking is a good idea in most cases but there are collaborative applications that may require its availability. After talking to your researcher about their specific requirement, you may find a way around having to use multicast. But, if not, you could use a separate SSID that supports multicast and peer to peer connections - you may also want to consider moving their port outside your firewall - blocking any University resources from the risks they create (you'd need to know the researchers' need to understand if you can do this without effecting his/her requirements). Regards, Jon Freeman Xirrus, Inc. 303-808-2666 From: Lee H Badman [mailto:[EMAIL PROTECTED] Sent: Friday, August 31, 2007 6:28 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Cisco LWAPP, multicast/peer to peer blocking modes We have 12 WiSMs at SU (24 controllers) and around 1,550 APs online. By default on the controllers under General System configuration options, Ethernet Multicast Support is disabled by default, and we chose to enable Peer to Peer Blocking Mode. We are being asked a by a researcher to change both of these settings to allow both multicast and peer to peer connections in the WLAN, and our first reaction is to grimace and gnash teeth a bit. Am wondering if anyone is actually allowing multicast on a large WLAN and seeing any problems, added load, or general observations worth noting? Same with peer to peer. Regards to the group- Lee H. Badman Wireless/Network Engineer Information Technology and Services Syracuse University 315 443-3003 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
