RE: [WIRELESS-LAN] Meru Question

[Frank Bulk]

Co-channel interference with neighboring APs is a real issue for offices in Manhattan and the like, but not much of an issue in the isolated realm of a defined campus.  If a company uses a Meru system with a single channel on the floor of a corporate building its not easy to play nice with your neighbors the floor above and below -- you can't tell them not to use your channel, and you had better not overly impact their APs' performance on that channel.  The top three things to do would be to work with their neighbors as much as reasonably possible to coordinate channel planning, install directional antennas, and take advantage of their AP's power control to minimize interference generated on other floors (not to speak of the building across the street).   Regards,   Frank From: Ruiz, Mike [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 27, 2006 8:47 AM To: [EMAIL PROTECTED]; WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: RE: [WIRELESS-LAN] Meru Question Technically you’re correct in that Meru could schedule a neighboring AP to some degree anyway.  That said if you have a neighboring AP on the same channel as Meru you have other problems.  Namely your design is flawed  The thing to do in that case is either move the channel off overlap or lower the power on the neighboring Meru AP so it doesn’t overlap. This isn’t really a Meru issue though.  If your overlapping AP’s were both Cisco you would be generating collisions between the AP’s and likely cause more delays than Meru would as it would be totalliy unpredictable.   Mike     From: Frank Bulk [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 27, 2006 9:20 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Meru Question   Mike:   Meru APs can use virtual carrier sense (see http://sysnet.ucsd.edu/~bellardo/pubs/usenix-sec03-80211dos-html/node12.html for an extreme example) to help manage timing access to the air.  By manipulating the time they are able to make clients and neighboring APs on the same channel wait longer then they would 'normally'.  This can impact non-Meru neighboring APs on the same channel because they wouldn't have as quick access to the medium as they would in a traditional 80211 configuration.  Does this match your understanding of Meru's technology   But you're absolutely right, co-channel interference will do the same thing, just that Meru's is intentional while co-channel interference is generally non-intentional.   Regards,   Frank   From: Ruiz, Mike [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 27, 2006 7:59 AM To: [EMAIL PROTECTED]; WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: RE: [WIRELESS-LAN] Meru Question Frank,             Any WAP will affect any neighboring AP on the same or overlapping channels.  What are you getting at here?   Mike     From: Frank Bulk [mailto:[EMAIL PROTECTED] Sent: Monday, June 26, 2006 6:31 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Meru Question   Don:   Meru's technology does have the potential to impact neighboring APs on the same channel that are not participating the Meru-based wireless network, but that should be an issue for a campus-based network, and I believe there are some tweaks that can be made to limit their impact on neighboring APs using the same channel.   As for this 'bug' in the 802.11b/g standard, I would be interested in hearing your Cisco SE's substantiation for this.  If this is real, I would like this brought to the surface for further scrutiny.    Regards,   Frank   From: Donald R Gallerie [mailto:[EMAIL PROTECTED] Sent: Monday, June 26, 2006 2:47 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] Meru Question Here at the University at Albany, we had Meru come in and give us an overview on their wireless offering.   From our vantage point, it does appear that Cisco is pushing the controller-based system so we decided to look at other vendors in this space.  As part of this effort, we asked Cisco to come in and give us an overview of their offering as if they didn’t already have a presence on campus.   One of the items that came up had to do with Meru’s method of distributing timeframes to clients (don’t know if I’m phrasing this correctly).  The Cisco engineers said that Meru’s methodology works well in a Meru-only rollout but that they would negatively impact other, non-Meru access points. Additionally, the said that there is a “bug” in the current 802.11b/g standard that Meru takes advantage of and that it may not be there in future (802.11n) standards.   Not that I would doubt anything Cisco says but has anyone heard any similar remarks or can anyone expand on Cisco’s claims?   Thanks….   Don Gallerie The University at Albany ********** 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/.