> On 6 Jan, 2015, at 22:45, Hal Murray <[email protected]> wrote:
> 
> GoGo provides internet access on airplanes.  They want to block YouTube 
> (and similar) to avoid overloading their thin pipes.  They are doing that by 
> intercepting https connections and presenting bogus certificates.

…WTF?

Look - if you *want* to block YouTube, then you block YouTube.  People might 
get a little annoyed about that, but it’ll probably be limited to minor 
grumbling.  You *don’t* fiddle with traffic to it.  There is something 
*seriously* wrong if that’s the first or best solution that came to mind.

I agree with the conclusion of the article, though.  There’s a straightforward, 
network-neutral, technological solution which actually solves the original 
problem.  Shame almost nobody’s heard of it.

Incidentally, I finally got my test setup running properly.  It now has cake 
running on each of two Fast Ethernet interfaces in the Pentium-MMX, which are 
bridged.  It is able to comfortably pass 50Mbps through that before it runs out 
of CPU grunt - but that’s 50Mbps total.  It doesn’t matter whether it’s all one 
way, all the other way, or half each.  I then set it up to simulate a 24/3 Mbps 
ADSL, and it did that with about 50% CPU time in soft-interrupt mode.

I haven’t tried cake2 yet.

The limiting factor may well be context switching, or at least interrupt 
handling overhead.  That’s quite expensive on x86 and on a full OS like Linux; 
far more so than on, say, an ARM running in a dedicated embedded configuration. 
 (ARM has banks of registers which are switched in, replacing the originals, 
for interrupt handlers, so it doesn’t have to hurriedly save all those 
registers before it can do anything useful.)  Bridging, and running *both* the 
traffic endpoints on other machines, rather than keeping one endpoint on the 
Pentium-MMX, improves the throughput markedly.

 - Jonathan Morton

_______________________________________________
Bloat mailing list
[email protected]
https://lists.bufferbloat.net/listinfo/bloat

Reply via email to