Warning Warning - don't touch the "N" AP's - they can poke you much like a porcupine. Do people really want tarantulas stuck to the ceiling everywhere?
A little design humor... Seriously though: < Philippe of Univ. of TN wrote>" Side note again: One thing is sure, Controller Based Architectures are really good at hooking you up then nickeling and diming you to death!" A great statement - can you image if today - when you purchased an upgrade of your edge Ethernet switches - if you had to buy a mother-ship of a controller to centrally manage, control, and monitor them? Of course not - that architecture was well over a decade ago in the wired world - and has been solved by centrally managing and monitoring highly intelligent edge devices over our friend SNMP and an NMS. Chad Frisby 303.406.3222 -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[EMAIL PROTECTED] On Behalf Of Philippe Hanset Sent: Tuesday, April 01, 2008 10:41 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Aruba's SCA vs. MCA whitepaper [was: Open Wireless in Higher Ed] Somehow I was expecting this ;-) If time permits, we will try to really formalize it... Our intention is really to measure if there is a noticeable difference between Meru and Aruba (and maybe between Cisco and Aruba). Since we already acquired Aruba Controllers for our Dorms, we are "hooked", only a true advantage from another vendor would make us switch! I can already tell you that we never exceed 80 Mbps download on either one of them (Aruba or Meru), using TTCP (memory to memory) on a Macbook Pro (Linksys adapters are slower) and that uploads are more around 30 Mbps or less. (APs are connected to Gig ports, using Gig capable midspan and regular 802.3af power, the TTCP receiving unit is non-limiting) BTW: have you seen the size of those Meru and Cisco APs...I'm not sure where to fit that in our drop ceilings, seriously! Side note again: One thing is sure, Controller Based Architectures are really good at hooking you up then nickeling and diming you to death! (AP license, IDS license, Firewall license, number of admin on system license, buy licenses for the redundant units as well...) I wonder what experience people have with Monitored Architectures like Colubris or what Proxim is developing these days? Philippe Univ. of TN On Tue, 1 Apr 2008, Don Wright wrote: > Hi Philippe, > We'd be very interested, as others are I'm sure to hear what you > find out from your testing. > -- > Don Wright > Brown University > CIS - NTG > > > > On 4/1/08 10:53 AM, "Philippe Hanset" <[EMAIL PROTECTED]> wrote: > > > Dave, > > > > At Univ of TN, our intention is to deploy 802.11n capable APs where our > > 802.11b/g AP are located right now, use one radio at 2.4 GHz (b/g only, > > no n) the second radio at 5 GHz (n and a). > > This should provide a decent access for b/g users and a fast lane for n > > users. > > I'm not sure that best effort on b/g will be good enough when you consider > > devices like Iphones or future Voice over WiFi devices. > > > > One aspect of this kind of approach will be the performance of coverage > > algorithms. n has such a wierd shape compared to b/g or a...I'm a little > > suspicious as how vendors will deal with n's behavior! > > > > As a side note: > > We are testing in our info-commons (the worse enviroment you can > > think of...tons of users and tons of APs) 802.11n APs from Aruba > > and Meru (we have just replaced locations of our existing Proxim APs > > with the test APs, and those n APs are surrounded by legacy Proxim APs as > > well) > > One week with Aruba, one week with Meru. We might test Cisco...TBD. > > Our main issue is to get enough people with 802.11n adapters, so we > > loaded our loaners laptop (30+...very successfull program BTW) with > > external 802.11n adapters (USB 2.0, Linksys). > > > > > > Philippe > > > > > >> Although the issue of co-channel interference is an important one, I think > >> it may be reasonable to assert that its importance will be reduced with the > >> adoption of 5 GHz 802.11n. With over 20 non-overlapping channels, I believe > >> it will be possible to design high-density, micro-cellular WLANs that do not > >> suffer from performance degradation as a resulting of co-channel > >> interference. Over time, I believe 2.4 GHz will be thought of as a > >> best-effort legacy technology for most enterprises. I'd be curious how > >> others are viewing this. > >> > >> dm > >> > >> -----Original Message----- > >> From: The EDUCAUSE Wireless Issues Constituent Group Listserv > >> [mailto:[EMAIL PROTECTED] On Behalf Of Charles Spurgeon > >> Sent: Monday, March 31, 2008 4:31 PM > >> To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU > >> Subject: Re: [WIRELESS-LAN] Aruba's SCA vs. MCA whitepaper [was: Open > >> Wireless in Higher Ed] > >> > >> On Wed, Mar 26, 2008 at 10:31:50PM -0500, Frank Bulk - iNAME wrote: > >>> I wish it was easier to evaluate the performance (not only aggregrate > >>> throughput, but also QoS) of the MCA and SCA products in various scenarios > >>> and density and usage, but unfortunately examining the impact of > >> co-channel > >>> interference on a large scale in variety of building types and > >> architectures > >>> with lots of APs and clients with realistic traffic patterns (in terms of > >>> type and longitudinally over time) is not currently possible with the > >> tools > >>> available. I think we would learn that there certain scenarios where one > >>> performs generally better over another. > >> > >> I, for one, would like to see more vendors step up and do the kind of > >> testing of co-channel interference issues that was described in the > >> recent Novarum whitepaper: > >> http://www.novarum.com/documents/WLANScaleTesting.pdf > >> > >> As a user of typical multi-channel equipment, I'm not focussed on the > >> SCA versus MCA debate. Instead, I would very much like to see more > >> real-world test results on how the typical multiple APs on multiple > >> channels (MCA) approach works at scale and under traffic loads. > >> > >> I think it's very interesting that the author of the Novarum > >> whitepaper is also one of the developers of the 802.11 MAC, and that > >> he states that he was "surprised at how easily we could drive these > >> systems to unstable behavior." > >> > >> I've heard complaints from the vendors whose gear was used in the > >> Novarum test. But I haven't seen any third-party tests commissioned by > >> those vendors to replicate the tests and show where the problems were > >> in the Novarum tests. > >> > >> I would be much more impressed by actual third-party test results > >> based on a significant scale layout like the one used in the Novarum > >> tests, rather than hearing complaints about the how the test was > >> unfair since it was done under the auspices of Meru. > >> > >> The problems of co-channel interference and wireless channel meltdown > >> under load are too important to be left to the marketing departments > >> of the wireless vendors. On our campus the community has been adopting > >> wireless networking at extremely high rates, and this technology has > >> become much too important to allow it to be supported this poorly. > >> > >> Isn't it long past time for more real-world scale testing like the > >> Novarum tests to be done to investigate the issues with CCI and > >> channel meltdown under load in 802.11b/g systems and to develop some > >> approaches for identifying and dealing with those issues? > >> > >> -Charles > >> > >> Charles E. Spurgeon / UTnet > >> UT Austin ITS / Networking > >> [EMAIL PROTECTED] / 512.475.9265 > >> > >> ********** > >> 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/. > ********** 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/.
