On 03/13/2012 03:35 PM, Blake Pfankuch wrote: > Thanks Pete, that does help. Now hopefully I can get someone who has > experience with 500+ devices running on a single one in a fairly small area > (High School Gym). There was a thread about this a couple of months back, I'm pretty sure it was after last November (but not absolutely sure); lots of discussion about density and Xirrrus was mentioned. My personal experience with Xirrus is certainly not high-density, and the "real" hospital certainly copes with a bunch (though I'm guessing 20-30 users per AP from how many APs they have distributed among rooms. They seem to do a bunch of their device telemetry on 802.11 but there are also some more dedicated frequencies/protocols for medical devices. (even the IV pumps alarm at the nurse's station...)
I do have some experience with full-duplex RF transceiver design, though, and the Xirrus configuration can't be easy to make work well. Not impossible, but difficult. -- Pete > > -----Original Message----- > From: Pete Carah [mailto:[email protected]] > Sent: Tuesday, March 13, 2012 4:32 PM > To: [email protected] > Subject: Re: Xirrus Wireless > > On 03/13/2012 02:34 PM, Blake Pfankuch wrote: >> I know this is a little outside of the traditional NANOG realm but... >> >> I have a customer looking at a fair number of Xirrus Wireless Arrays for >> 802.11a/b/g/n implementations and am looking for some real world insight >> into them. On the cover they look cool, the white papers look cool, but I >> am yet to find technical commentary from a real person on these devices. >> Looking at the XN line, and just curious if anyone has deployed these, >> supports these or knows anything about them. > I can only speak from indirect experience; the rehab place where my wife is > staying for a bit uses 4 or 5 of them (older, probably not current, > flying-saucer-like boxes suspended from the ceiling at hallway > junctions) and there, at least, they appear to work pretty well. The > particular ones don't appear to my laptop to do 11a. However, I don't think > there is any significant user density just from watching the nifty > directional light display, so this may not mean much (I'd guess 3 to 10 > users over the whole building including smartphones and a couple of pieces of > medical equipment that isn't used much). Also there is no IT (or any real > technical maint) guy on-premises to talk to so I can't ask about any other > aspect. > > The local real hospital uses a Cisco system (or at least Cisco APs; don't > know about the AP manager box) which really does appear to work well; I'd > guess several hundred APs with lots of full-time medical gear, and a "guest" > network which is behind a rather draconian firewall (wouldn't let me ssh out > to a non-standard port (65k range), for example; I had to fix myself a 443 > ssh port for the time we spent there a couple of months ago... Blocked 25 > outgoing; I don't blame them for that, however they also blocked 465 (but > allowed 587)). > > I suspect if I wanted 2.4-only I'd go with ubiquiti, but I don't have any > experience with them, and their "unifi" boxes don't (yet) come in 5gig. And > they don't appear to have independent APs in each box, though I don't know > how well the "directional" antennas in the Xirrus actually separate things; > even a 100mw transmitter may well overwhelm all the other local receivers > unless there is a bunch of shielding inside the enclosure (and maybe even > then...) If 802.11 was frequency-split like the cell system it would help > such systems a bunch. > > -- Pete > >> Thanks! >> >> Blake >> > >
