[AusNOG] Stupid web browser behaviour Was: My Predictions for the ISP Industry

[Karl Auer]

On Thu, 2012-03-15 at 13:20 +1000, Craig Askings wrote:
> For example on my dual stack connection at home when I go to 
> (http://labs.apnic.net/measureipv6/) it works first time with Firefox 
> but fails with Chrome because it has yet again decided to stop asking 
> for AAAA records.

I may be just displaying the depth of my ignorance regarding Chrome
here, but doesn't Chrome implement "happy eyeballs"? That is, it tries
AAAA and A simultaneously, then sticks with what works best. This is
from section 4 of the draft RFC draft-ietf-v6ops-happy-eyeballs-07 (I
just grabbed the first one I saw, there might be a later version
available):

   "[...] the client learns whether
   connections to the host's IPv6 or IPv4 address were successful. The
   client MUST cache information regarding the outcome of each
   connection attempt and uses that information to avoid thrashing the
   network with subsequent attempts. For example, in the example above,
   the cache indicates that the IPv6 connection attempt failed, and
   therefore the system will prefer IPv4 instead. Cache entries should
   be flushed when their age exceeds a system defined maximum on the
   order of ten minutes."

So if IPv6 is somewhat slower responding, or doesn't respond at all,
even due to a transient fault, Chrome will stick with IPv4 for ten
minutes.

I stress that I have no personal experience of Chrome; this is pure
theory.

Regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)
http://www.biplane.com.au/kauer

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