Ethan: Thanks for addressing my points so precisely and honestly.
One of the things I forgot to mention on the list of shortcomings for consumer APs in enterprise settings was multi-BSSID and/or multi-SSID support. Define flaky? Same as you, I meant the AP's software code. Perhaps the custom code you use doesn't make this an issue, but one only needs to peruse the linksysinfo forums to know that there are lots of issues with SOHO routers, and Linksys is not a vendor you can call and actually receive plausible enterprise support. Putting all the APs in the same L2 domain has been done before, and I would only recommend it for the smallest deployments. Broadcast traffic, on the wireless and the wireline side, will absolutely ruin performance, as you pointed out, can cause AP issues. As you pointed out, the L3 roaming concern prevents you from segmenting the APs as you wish. If you put together a presentation in electronic form I'm sure we'd all love to see a link to it when you're done, perhaps after you've presented the material and had a chance to incorporate the response into the document. Kind regards, Frank -----Original Message----- From: Ethan Sommer [mailto:[EMAIL PROTECTED] Sent: Wednesday, September 06, 2006 2:08 PM To: [email protected] Subject: Re: [WIRELESS-LAN] Linksys APs as enterprise solution We have just deployed over 120 Linksys WRT54GLs in our dorms. So far, everything has been working well. We used dd-wrt modified slightly (so that it acts as an AP and gets a dhcp address) and have each access point check in with a server every 2 minutes to report that they are up and who is connected to them. Where possible we are using PoE with linksys PoE adapters fed by a web enabled power switch (http://www.webpowerswitch.com/) which we can control using a perl script. (We can't do it in a few dorms which have "split jacks" running two jacks over one cat5 cable.) I believe we have addressed all of the conserns below, but we're very early in the project so time will tell. I'll detail how we have dealt with them below: Frank Bulk wrote: > I think this has been thrown out on the listserv before. The major > objections tend to be: > a) lack of external antenna connectors > Linksys WRT54G(L/S) have RP-TNC connectors. The other AP I'd consider is BuffaloTech's broadcom based APs which have SMA connectors. > b) lack of adjustable output power on some units (this may not apply to the > Linksys in question) > The APs can be adjusted from something less than 28mw to 250mw. Some people on wrt related forums have expressed concerns about overheating and stability at higher than about 70mw, but we've been running over one hundred of them at 200mw all summer (many without AC) without any problem so I suspect that that's simply not a problem or that manufacturing has gotten better. > c) lack of management system for these APs, especially in regards to RF > planning and control > We have written our own management system. So far it monitors uptime, reboots APs if they are down or on demand, and monitors usage (including pretty graphs) of each ap, the system as a whole, or a subset of the aps. The ap reports what channel it is on, but doesn't have any smarts to suggest a better channel yet. We also use the APs to detect rogue aps. (we do a site survey every night and we get a nightly report by e-mail) > d) generally a more flaky radio in comparison to enterprise gear, but this > is hard to quantify and I'm sure some objections would be raised. > Define flaky... What we have noticed to be flaky is the network stack of the OS. If there is a broadcast storm on the network several APs will stop checking in and need to be rebooted. I believe they are still "functioning" though. Right now we have three or four APs with 15-20 clients associated to them, and we aren't getting complains about it. We haven't had time to go see how well they are working since the students moved in though. > e) poor roaming experience: there's no pre-auth key caching as in WPA2, so > every roam would require the full 8-way handshake. > We aren't using WPA2 so I can't speak there. I can say that we have been experimenting with wireless voip phones (specifically the linksys WIP300 and UTStarcom F3000) and we can walk around large buildings without audibly noticeable roaming drops. > f) all roaming would be L3 roaming: because each AP NATs the clients (this > might be different in the OPENWRT build), every roam would likely require a > full DHCP cycle on the client, breaking any applications that require > session persistence. > > We set up the routers as APs, and all our wireless is on the same L2 broadcast domain, so that's not the case. We'd love to be able to subnet the wireless into more vlans but are afraid of the L3 roaming. As it is, we (3 days after upperclassmen could move in) are seeing about simultaneous 800 users at peek times, which is quite a bit of broadcast traffic. However, the APs seem to be handling it quite well. So, I'm not sure if I'd recommend it yet. I plan on preparing a talk for a local conference in January on the TCO of the system, so I'll be attempting to keep track of how much time it takes to maintain it. So far it seems relatively trouble free other than unrelated problems like students unplugging the routers (we put APs in RA's rooms in a few dorms which we couldn't install ethernet in public spaces this summer.) -- Ethan Sommer UNIX Systems Administrator Gustavus Adolphus College 507-933-7042 [EMAIL PROTECTED] ********** 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/.
