Bug#268631: force preference of IPv4 over IPv6
> In the world I live in, my ISP was among the very first here to
> deploy native IPv6 on DSL *years* ago and is actively seeking IPv6
> peering opportunities with as many networks as possible.
That is great. Do they artificially slow down IPv4 in order to ensure
that IPv6 is faster?
> IPv6 connections here are usually as fast if not faster than IPv4
> connections.
Maybe within their network, but I don't believe this for global
connectivity. Periodically measure sustained bandwidth and latency to
a distant host at another IPv6-loving ISP, say ftp.ie.debian.org, over
both IPv4 and IPv6. That would be a best case scenario. You will not
find IPv6 to be faster or more reliable than IPv4.
> I suggest you fix your world ...
That is silly. It will be extremely rare for IPv6 to be *faster* or
*more reliable* than IPv4, for quite a while. This is because ISPs
have these things called "customers" who want to access this thing
called "The Internet" by which them mean connecting to hosts like
$ for h in www.comedycentral.com www.cnn.com slashdot.org www.ietf.org \
www.google.com www.mit.edu www.yale.edu www.cs.cmu.edu \
www.whitehouse.gov www.army.mil; do
for p in a aaaa; do
host -t $p $h | egrep address | head -1
done
done
a1481.b.akamai.net.2b55293e.1.cn.akamaitech.net has address 92.122.124.11
www.cnn.com has address 157.166.255.18
slashdot.org has address 216.34.181.45
www.ietf.org has address 64.170.98.32
www.ietf.org has IPv6 address 2001:1890:1112:1::20
www.l.google.com has address 216.239.59.103
www.mit.edu has address 18.7.22.83
elsinore.cis.yale.edu has address 130.132.51.8
MICHELANGELO.SRV.cs.cmu.edu has address 128.2.203.164
e2561.b.akamaiedge.net has address 92.122.114.135
www1.ahp.us.army.mil has address 143.69.249.10
As you can see, popular server do not provide IPv6 access. Even the
rare host that does also provides IPv4 that is at least as performant.
ISPs must therefore make it their first priority to make IPv4 fast &
reliable. Whining at them won't help. What *would* help would be
taking technical measures that allow ISPs to field IPv6 without
breaking things that already work. And wouldn't it be great if those
very same technical measures would also allow servers like those above
to advertise an IPv6 address without endangering performance in
communicating with IPv6-enabled clients? Then hosts could advertise
IPv6 addresses without risk of breaking things that already work. If
that were the case, perhaps they would. Then we would have a viable
path to an actual transition.
--Barak.
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