simon at limmat.switch.ch simon at limmat.switch.ch
Thu May 31 23:02:40 UTC 2007

Donald Stahl writes:
>> I guess we have different definitions for "most significant
>> backbones". Unless you mean they have a dual-stack router running
>> _somewhere_, say, for instance, at a single IX or a lab LAN or
>> something.  Which is not particularly useful if we are talking about
>> a "significant backbone".
> Rather than go back and forth- can we get some real data?

Yes please, I like data!

> Can anyone comment on the backbone IPv6 status of the major carriers?

Our three Tier-1(?) upstreams AS1299, AS3356, and AS3549 all provide
IPv6.  Only one of them has dual-stack on our access link, for the
other two we have to tunnel into their IPv6 "backbone" through their
IPv4 backbone.

I don't know exactly how their internal IPv6 networks are built,
although with one of them I'm sure they use/used "6PE", i.e. IPv6
"tunneled" over an IPv6-agnostic MPLS core (learned this from trouble
tickets, sigh).  But all three offer decent IPv6 connectivity -
e.g. we rarely observe gratuitous routing over an ocean and back, or
order-of-magnitude RTT or loss-rate differences between IPv4 and IPv6.

Our own backbone has been dual-stack for a couple years now, but I
guess this just shows that we can't be a "major carrier" - same for
many other national "academic" backbones as well as GEANT, the
backbone that interconnects those.  Same in the US with Internet2 and
the regional research/education networks.
Simon. (AS559)

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