On Sat, Jan 24, 2015 at 8:35 PM, David Lang <da...@lang.hm> wrote: > On Sat, 24 Jan 2015, dpr...@reed.com wrote: > >> On Thursday, January 22, 2015 1:19pm, "Richard Smith" >> <smithb...@gmail.com> said: >> >> >>> On 01/22/2015 04:18 AM, David Lang wrote: >>> >>> >> Recently, we picked up the 11th floor as well and moved many people up >>> >> there. I got a 3rd AP (another TP-Link AC1750) and set that one up on >>> >> a free channel with a different ESSID. >>> > >>> > I like to put all the APs on the same ESSID so that people can roam >>> > between them. This requires that the APs act as bridges to a dedicated >>> > common network, not as routers. >>> >>> That's the ultimate plan but for convenience of being able to easily >>> select what AP I'm talking to or to be able to tell folks to move from >>> one to another I've got them on different ESSIDs. It also helps me keep >>> track of what RF channel things are on.
My usual use case for using different APs is to find an error in the campus. When someone tells me that "Lupin-lodge" is down, I know exactly which machine to check. If everything was named Lupin, I'd have to check far more than one AP, and to ask approximately where on the campus they were. >> >> >> >> A side comment, meant to discourage continuing to bridge rather than >> route. >> >> There's no reason that the AP's cannot have different IP addresses, but a >> common ESSID. Roaming between them would be like roaming among mesh >> subnets. Assuming you are securing your APs' air interfaces using encryption >> over the air, you are already re-authenticating as you move from AP to AP. >> So using routing rather than bridging is a good idea for all the reasons >> that routing rather than bridging is better for mesh. > > > The problem with doing this is that all existing TCP connections will break > when you move from one AP to another and while some apps will quickly notice > this and establish new connections, there are many apps that will not and > this will cause noticable disruption to the user. I am under the impression that network-manager and linux, at least, tend to renegotiate IPv6 addresses on an down/up, and preserve ipv4. > > Bridgeing allows the connections to remain intact. The wifi stack > re-negotiates the encryption, but the encapsulated IP packets don't change. While I actually agree with dlang on having all the same ssid and bridging, and not routing, on a conference, as well as with the idea of disabling broadcast (and I assume direct connectivity between two people seated side by side), it is a pita: More than once I've wanted to share a git tree with someone right next to me. I try to hand them my ip to grab the tree, and they can't even ping me, so I end uploading it somewhere, and he or she downloading it from there. Similarly, breaking interconnectivity precludes sane usage of in-conference In my case, since choosing to live in a routed, rather than bridged world, I have modified the nailed up tools I use to be more connectionless. Instead of ssh (tcp), I use mosh-multipath (udp), which is far superior for interactive shells in lousy wifi environments. For vpns, I switched to tinc, which will attempt direct connections over udp, and tcp on both ipv4 and ipv6. For access to google, I adopted quic in my chrome browser. Since doing all these things I rarely notice losing a nailed up connection or migrating from AP to AP. Additionally I use babel (where I control the network) and ad-hoc wifi to transparently migrate from AP to AP, and (often) from AP to wired to AP to wired as I change locations, also with no loss in connectivity. I don't expect the scale userbase to have made these adjustments in behavior. :/ > > I do this with the wifi on it's own VLAN (actually separate VLANs for 2.4 > and 5GHz) and have the APs configured not to relay broadcast traffic from > one wireless user to another. This cuts down a LOT on the problems of > broadcasts. > > In about a month I'm going to be running the wireless network for SCaLE > again, and I would be happy to instrament the network to gather whatever > info anyone is interested in. I will be using ~50 APs to handle the ~2800 or I will look into some tools bismark and others have. Will you attempt to deploy ipv6? > so devices that show up, with the footprint of each AP roughly covering a > small meeting room (larger rooms have 2 APs in them, the largest room has 3, > and I'm adding APs this year to cover the hallways better because the ones > in the rooms aren't doing well enough at the low power settings I'm using) I am of course interested in how fq_codel performs on your ISP link, and are you planning on running it for your wifi? > David Lang > > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel -- Dave Täht thttp://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks _______________________________________________ Cerowrt-devel mailing list Cerowrt-devel@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cerowrt-devel
