

Bufferbloat: Dark Buffers in the Internet - kpi
http://cacm.acm.org/magazines/2012/1/144810-bufferbloat/fulltext

======
cypherpunks01
Overall, does anyone have a feel for how close we might be to a congestion
collapse on today's internet? I've been reading about this for a few years now
and have obvious worries about real solutions not being implemented until
after the storm hits.

Or is this being overstated? Are there mechanisms in place that would mitigate
or prevent large-scale congestion collapses of this kind?

~~~
EricBurnett
The worldwide internet infrastructure is remarkably fragile. I can think of a
few example off the top of my head where it's been abused or broken:

1\. China 'borrowing' traffic:
[http://arstechnica.com/security/news/2010/11/how-china-
swall...](http://arstechnica.com/security/news/2010/11/how-china-
swallowed-15-of-net-traffic-for-18-minutes.ars)

2\. Myriad undersea cable cuts slowing / segmenting the internet

3\. Juniper routers going down:
[http://www.networkworld.com/news/2011/110711-internet-
outage...](http://www.networkworld.com/news/2011/110711-internet-
outage-252851.html)

4\. There was an incident (2 years ago?) where an European ISP broadcast a
low-cost route incorrectly and blackholed a large portion of the internet,
although I can't find a link right now.

With respect to buffers specifically, AT&T's network issues when the iPhone
launched were largely self-inflicted by having overly large buffers:
[http://blogs.broughturner.com/2009/10/is-att-wireless-
data-c...](http://blogs.broughturner.com/2009/10/is-att-wireless-data-
congestion-selfinflicted.html)

So yes, widespread issues are certainly possible. The internet is not nearly
as resilient as people would like to believe.

------
SMrF
I admit, though I found the topic fascinating I only had time to skim. But I
did notice something which may be of interest to others: CeroWrt is a branch
of OpenWrt geared towards fixing the buffer problem on your home network. So
I'm guessing if you get this configured correctly you might see significant
improvements in latency. I'm intrigued.

I posted it as a separate topic here:
<http://news.ycombinator.com/item?id=3461790>

------
jimrandomh
Yep, I definitely see this from time to time, especially over mobile networks.
Interestingly, most of my problems went away when I started using OpenVPN. It
connects with UDP to my Amazon EC2 VM, which is close enough to the internet's
core that everything after that is low-latency. I'm not sure why this works,
but it does suggest a practical testing ground for bufferbloat-workaround
strategies: you can't make the rest of the internet adopt your weird new
protocol, but you can install it on a VM, and route all your traffic that way.

As an added bonus, this gets you security on untrusted networks and a static
IP. And you could potentially use this sort of trick to get a cool multi-homed
connection, although there's no software for that currently. It'd be
interesting to see what possibilities there are when combining a fast but
bufferbloated or high-latency connection, with a slow but low-latency
connection.

------
jvehent
Feel free to try this at home:
[http://wiki.linuxwall.info/doku.php/en:ressources:dossiers:n...](http://wiki.linuxwall.info/doku.php/en:ressources:dossiers:networking:traffic_control#a_word_about_bufferbloat)

------
Merrack
Must be nice to have Vint Cerf on hand to consult on your networking issues!

------
jamesgeck0
I've observed behavior similar to this from my cable ISP and chalked it up to
malice. It's interesting that the problem is so widespread, but apparently not
very well understood by so many providers.

~~~
pja
Mobile data links are especially prone to this kind of madness in my
experience. I quite often experience data links which sit at 4-5s ping times
for extended periods.

------
pors
Wow, just scrolling to the bottom if this article took ages. #sent2kindle

