Good info- thanks. Lee
>>> [EMAIL PROTECTED] 4/9/2007 10:04 AM >>> In addition, at UTD, during our transition, we are running Meru systems right alongside the legacy Proxim AP-2000s and AP-4000s we're replacing (same building, same floor, adjacent cells). I've never seen any issues with this setup. And, as Michael Ruiz said, Meru did go through a *re*certification process just to prove this point. --Mike On Apr 9, 2007, at 8:58 AM, Ruiz, Mike wrote: > Id like to share two pieces of info on this. We have been running > meru as a neighbor to several other smaller wireless installs and > have never seen any issues that were unexpected. This is both in > an overlapping and a non-overlapping channel scenario. > > Secondly, a short time ago we hosted an independent lab who tested > for the bad neighbor issue. They were unable to find any problems. > > I would expect the wifi recertification should also speak worlds on > this alleged issue. > > - > Michael Ruiz > - > Sent using Exchange Mobile Active Sync > > -----Original Message----- > From: "Lee Badman" <[EMAIL PROTECTED]> > To: "[email protected]" <WIRELESS- > [EMAIL PROTECTED]> > Sent: 4/9/2007 9:05 AM > Subject: Re: [WIRELESS-LAN] microcell vs virtual cell > > I've heard a growing number of anectdotal instances where the virtual > cell model causes problems for neighboring WLAN systems by trying to > control their timing parameters and such- though can't say that I have > talked to anyone directly that has experienced this supposed "bad > radio > neighbor" effect. Has anyone who actually uses the virtual cell > hardware > had reports from nearby systems of this negative effect, or is this a > bit of a competitors' urban legend? > > Regards- > > Lee > > > > > >>>> [EMAIL PROTECTED] 4/7/2007 12:15 PM >>> > We too are Meru users, since December 2005. Michael has done a very > good job articulating details of the Virtual Cell. I would be pleased > to provide information if needed. Additionally I would be pleased to > talk offline about some interesting technology we are alpha-testing > from > Meru. For what its worth, I wouldn't recommend doing Wi-Fi any other > way. > > In the interim, I recall some independent layer 1 testing and > operational testing done out of the UK a while ago. I'm trying to > track > down that information. > > Mike > > > - > Michael G. Ruiz, ESSE ACP A+ > Network and Systems Engineer > Hobart and William Smith Colleges > Information Technology Services > > P.315-781-3711 F.315-781-3409 > Team Leader: Derek Lustig ([EMAIL PROTECTED]) > > > Did you know that HWS Students, Faculty, Staff, Alums, etc > can purchase computers, accessories, electronics and software > at a discount through our partner CDW-G? > http://www.cdwg.com/hws/ > - > > > ________________________________ > > From: Michael Griego [mailto:[EMAIL PROTECTED] > Sent: Fri 4/6/2007 6:49 PM > To: [email protected] > Subject: Re: [WIRELESS-LAN] microcell vs virtual cell > > > > Where virtual cell deployments really shine is in a couple of ways: > > 1. By timing the transmissions of both the APs and the clients, they > cut *way* down on the number of collisions and retransmits. This > alone is what causes the throughput of a normal AP to completely tank > after 20-30 users. So, by cutting down on the amount of waisted air > created by the random backoffs and the collisions themselves, you > gain quite a bit of usable throughput and the ability to reliably > support more than 20 users (since the available spectrum can be > equally divided without the clients fighting like a bunch of > siblings). > > 2. By moving to an almost TDMA approach, 802.11g clients get better > performance when 802.11b clients are sharing the cell than they would > with traditional APs (at least this is true for Meru). This is > because the AP will give each client the same amount of air*time* > instead of the same number of frames, allowing the 802.11g client to > transmit more data before again having to wait on another client. > > 3. Most people don't realize (or it just doesn't dawn on them) that > you *can* run all 3 channels in a virtual cell deployment. You do > have to install more APs to support this configuration, but, by doing > this, you get 3 virtual cells spanning your campus and all of the > available bandwidth that goes along with it (which, for the reasons > listed above, is more than you would get using a traditional 3 > channel deployment, making your actual aggregate available throughput > much closer to the 162Mbps theoretical max for 2.4GHz usage). > > One of the other nice benefits of virtual cell deployments is the > lack of client-initiated roaming. This is especially useful for > cutting down roam times when the WLAN is 802.1x authenticated (and it > doesn't require PMK). Since, even though the client has moved his > association to a new physical AP, he's still talking on the same > channel and to the same BSSID, he has no clue that he has roamed and > his session state has been seamlessly moved by the controller. > > I'd be happy to discuss (offline) our Meru system with anyone who'd > like to ask questions. > > --Mike > > On Apr 6, 2007, at 3:30 PM, Ringgold, Clint wrote: > >> I am interested in the findings as well. My concern is the actual >> throughput. It would seem to me that a virtual 3 ap setup would be >> 54MB >> while in a microcell it would be 162MB....Potential. >> >> I hope I'm wrong and or can get clarification. >> >> >> >> -----Original Message----- >> From: Scholz, Greg [mailto:[EMAIL PROTECTED] >> Sent: Friday, April 06, 2007 3:59 PM >> To: [email protected] >> Subject: Re: [WIRELESS-LAN] microcell vs virtual cell >> >> I am also interested in anything you find. >> >> >> -----Original Message----- >> From: Steve Fletty [mailto:[EMAIL PROTECTED] >> Sent: Friday, April 06, 2007 3:33 PM >> To: [email protected] >> Subject: [WIRELESS-LAN] microcell vs virtual cell >> >> Is there any scholarly or technical data/analyis of the > single-channel >> virtual cell architecture vs the traditional micro-cell WIFI >> achitecture? >> >> I don't want to hear from vendors. I don't want bake-off results or >> vendor white papers. I'd like to know if there's any hard science >> comparing the two contrasting schemes. >> >> -- >> Steve Fletty >> Network Design Engineer >> University of Minnesota >> >> ********** >> 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:// <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/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
