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Why PyCon 2010's Conference Wi-Fi Didn't Melt Down
jafo writes "There's been a lot of teeth gnashing going on recently about broken wireless at conferences. We just wrapped up PyCon 2010, with around 600 (out of 1,000) attendees simultaneously accessing the volunteer-run network, and response has been fairly positive. 2.4GHz (802.11b/g) continues to be problematic, but most users were on 5.2GHz (using 802.11n) and associating at 130mbps, with a 100mbps link to the net (though after the fact we found that 35mbps would have sufficed). My PyCon 2010 wrap-up reveals all the secrets of how we did it, including pretty bandwidth and user graphs."
Editors, please do your job before you accept a story - that's an easy way to make Slashdot much better. In this particular story, it would have been easy - no research required. As I'm sure almost everyone here knows, m != M. Also, what is wrong with "b/s" instead of "bps"? (Also, how do I write non-ASCII characters here?)
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
They redirected all requests to goatse.
The AP he used was a Netgear WNDAP350. There was a typo in the article.
Because of the notorious slow conference WiFi's I have learned a new trick...
I use 3G networks. Since I live in Europe it would be expensive except I get pay-per-day for the country and that averages around 4 to 5 USD per day. That is great considering I can get 3G within restaurants, in my hotel room, and where ever else... Beats having to figure things out with the Wifi...
"You can't make a race horse of a pig"
"No," said Samuel, "but you can make very fast pig"
Even though it's just a short report, it's going to be very valuable for anyone doing similar work, be it for a conference or for a more permanent setup. No textbook is going to protect against those "oh crap, why didn't I think of it before?" moments like some actual experience would, and this posting is the next best thing after actually having someone with experience on site. And this works for any field of applied technology, not just wireless networking.
So, thanks and be back with some more soon!
This is Slashdot. Common sense is futile. You will be modded down.
http://serverfault.com/questions/72767/why-is-internet-access-and-wifi-always-so-terrible-at-large-tech-conferences
[quote]This was caused by us doing our own RJ47 crimping, which I really wanted to avoid.[/quote]
I really like to avoid doing RJ47 crimping, myself. Results are always totally unexpected.
IETF meetings are larger (1200+ typically), and basically everyone has an uses a laptop / pda, so they make for a demanding wireless environment. After some really bad experiences, resources were put into this, and the last few years, things have really improved.
What we have found is that
- it is necessary to have good gear (not all access points are created equal)
- To serve a lot of people, lower the power per access point, and put in a lot of them. Raising the power because of poor reception is a mistake.
- having both 2 GHz and 5 GHz networks really helps.
- telling attendees how to turn off "ad hoc" mode on their computers really helps.
- tracking down ill-configured boxes doing bad things on the network really helps.
Having said that, most recent IETF meeting sponsors have chosen to pay for professional wireless network providers. This is not trivial, and there is no better way to cause a flame war than to have the WLAN melt down.
The bimonthly IEEE 802.11 standards meetings are co-located with other 802 wireless working groups (802.15, 16, et al.) and regularly have attendance from 600-1000 persons, substantially all of whom are active on 2.4GHz (802.11b/g) substantially all the time the meetings are in session (it's required to register session attendance, upload and download documents, etc., but is largely used for Internet-based multitasking). These networks have worked flawlessly for years. They are specially-built for the meetings by VeriLAN Event Services, a company specializing in network services for special events. Their web site claims that they have supported events with up to 5000 simultaneous users.
I don't like the dual-band routers much - they always seem to do a crap job serving both bands, even in the rare cases that the router supports it.
$300 each for those Netgear APs sounds ridiculous when you can get carrier-grade equipment (such as Ubiqiti Rocket series units) for far less. Instead of getting dual-band stuff, just set up independent 2.4 GHz and 5 GHz networks.
retrorocket.o not found, launch anyway?
FTFA:
Crimping your own RJ45 should be avoided
Author should have said "testing should NOT be avoided".
I hate it when people say such things. A cable tester costs $15 and you neglected testing. Don't say "crimping your own RJ45 should be avoided". That's blaming someone else for your idiocy.
8 of 13 people found this answer helpful. Did you?
Learning is good and you were successful for the most part. Regardless of the downplay of comments you'll receive here on /. on what you did, it's what you took away from it and how to make it better for next year is what will make you great. That's how we all learn is by things like this. Anyone to admit otherwise is a more than likely a liar.
Any "idiot" that's been in IT and networking knows HOW to crimp their own connectors properly so that they work reliably.
If you can't trust your people to do the job correctly, then yes you may be forced to buy pre-made patch cords. This doesn't mean there's something inherently wrong with doing your own crimping; you just have to do it properly.
Tummy sponsors some hosts for the Fedora Project (I'm a Fedora contributor) and they're just all around good people. If you're looking for hosting give them a serious consideration: http://tummy.com/
"but most users were on 5.2GHz (using 802.11n) and associating at 130mbps". It should say 802.11a, not 802.11n.
Hmmm.... that's odd.... the Cylons must have managed to just miss all of Picon's wireless access points with their barrage of nukes. Or maybe it was just part of their "plan" all along?
PPTP? People should know better. PPTP is very weak. OpenVPN and IPSec are much better all around.
This year I tried to get public IPs again, but we just weren't able to get any meaningful number of them. So, we had to do NAT. This worked well, and I had no complaints beyond the first one: one of the guys couldn't establish a PPTP connection. I had forgotten to load the NAT protocol modules... I loaded those up and it went smoothly after that.
And you think that's going to be more likely to happen in future years?!
Next time, set up IPv6. Use 6to4 tunneling if you can't get an actual IPv6 drop from the network provider. But just get IPv6. Then everybody will have a public IP.
Need a Python, C++, Unix, Linux develop
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
There's a certain type of person who thinks that simple statements of truth are either wrong, stupid, or unnecessary. These people had a field day ridiculing Newton when he presented his 3 laws of motion.
take a bunch of bluebloods who have maids and chauffers, their number one 'business' idea is of course 'dont do anything yourself, not even wipe your own ass. you are too important for that and shouldnt get involved in minor operational details. stick to your core competency'. then wait a few decades for the cancer to spread... despite numerous unmitigated disasters like Vietnam, Detroit, and the Iraq War.... congratulations! you destroyed America!
zipperhead is a racial term for some kind of Asian. Are you sure that's the term you ment to use?
I think that phrase is "WHO DAT?"
RTFA.
If your read further, he said that the issue wasn't the WIRE connection, it was the little plastic snaps that lock the ends into the jack.
"the crimp on ends had the tabs in fairly close, so unless you bent them up before plugging them in, they wouldn't click in place."
"Because of this, we had several of the Ethernet connections come loose"
He said he'd avoid it because:
1) it's harder to get the good quality control (both physical crimp, individual part quality & total assembly), especially with Volunteers like he had.
2) It takes a LOT of time. He also noted that they didn't have enough crimpers to have multiple people crimping.
With pre-terminated cables with strain relief, you hopefully avoid both those issues, at the addition of a little cost.
I sort of agree with him: preterminated cables would save lots of time, and avoid having to buy multiple crimping tools & a tester to get a minimal speed/quality boost.
This is nothing, have a look at the setup at 26c3 last year.... Full 802.11a/b/g/n, DEC and GSM !!!!!!
* My laptop only does 2.4ghz n, and I thought that was par for the course? Are laptops with 5ghz N really that common?
* There is clearly a quality difference among access points, but how do you tell in advance which equipment will work and which won't?
is competition good, or is duplication of effort bad?
For fuck's sake, he was offtopic and rambling but you guys on the right need to stop lying about what people are saying.
He did not say government == good OR business == bad. You completely made that up, and used it as justification for calling the poster an idiot. Outside of politics, this sort of dishonesty is considered disgusting. But in the modern incarnation of the republican party, it's wholly encouraged.
You Glenn-Beck-listening assholes turn moderate health care regulation into a "government takeover". Anything that could even remotely be labelled progressive or liberal is instantly tarred as socialism. It sucks. You guys just don't care about reality anymore -- you just want everything to fit in your Ayn-Rand-inspired stereotypes.
This year's FOSDEM in Bruxelles had over 2400 unique MAC addresses and 3600 visitors a day(source). We enjoyed a 1Gbps pipe, and far from saturated it.
It was overall of excellent quality, though there was a glitch in at least one of the hacker rooms where the operators had to upgrade the AP firmware. The geographic setup was more broken out: FOSDEM happens at the Universite Libre de Belgique (how appropriate), with talks in lots of classrooms spread across a few buildings.
It would be useful for everyone if they could post a writeup of their infrastructure.
Misleading titles? Inflammatory blurbs? Keep in mind that Slashdot is a tabloid.
A good choice for AP is this
The real trick was getting APs that would do 802.11n on both radios at the same time. Most APs are not able to do N on both radios. So we ended up using the Netgear DWNAP-350, a $300 AP but it does support lots of features including gigabit Ethernet, N on both frequencies at the same time, PoE...
The Netgear WNDR3700 can't?
I wouldn't exactly call PyCon's Wi-Fi a success, but it was better than in years past. The venue changes every two years, so all the bugs have to get worked out in each new location then it's better the second year. I mostly used my iPhone on 3G and stayed off of Wi-Fi. The Hyatt must have had a micro-cell in the bldg because I had a strong signal 2 floors below street level.
If you tried to use wi-fi during the keynote session in the morning, it was slow as molasses. During the regular conference sessions it was more reasonable.
During Guido's opening talk he took questions via the twitter feed. That could have been painfully slow but it wasn't. It's not that twitter takes up much bandwidth, but the website serving up the feed and everyone hitting it could have been.
"You'll get nothing, and you'll like it!"
GAH. Somehow I typed this all up but forgot to hit submit...
My experience is that in addition to few routers/APs doing simultaneous dual-band, many don't allow you to do different modes on the two bands.
802.11n degrades severely in the presence of legacy devices, and it's a spectrum hog. So N in the 2.4 GHz band is a bad idea - my experience is that every 2.4 GHz N solution I've worked with has performed worse than a good 802.11g router with an external antenna.
802.11n works pretty well in the 5 GHz band - very few legacy devices and plenty of spectrum.
Nearly all dual-band routers/APs also now use internal antennas. Routers/APs with internal antennas suck. Period. It is far easier to find singleband routers that support external antennas (and singleband antennas) than dualband routers that support external antennas.
My own apartment setup is:
802.11g router with sector antenna running DD-WRT
802.11n router configured as an AP in the 5 GHz band, running "n-only" mode
Each network has a slightly different SSID so I can explicitly choose which network to use.
I would reccommend something like:
1) A 2.4 GHz network of G-only units with external antennas like the Ubiqiti Bullet2 or Bullet2-HP
2) A 5 GHz network of N-only units with external antennas
Very few people have equipment capable of 802.11a but not 5 GHz N, and forcing N-only on the 5 GHz network will improve performance. If you really want support for "legacy A" users, install a third network on a different set of channels.
retrorocket.o not found, launch anyway?
So some people did their job, and they write themselves a news story celebrating themselves?
I wish that my laptop supported 802.11n. I was stuck on g networks and in most rooms I had no wifi connectivity. (Could barely give a lightning talk as no internet was available to show a demo)
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
No, I will not work for your startup