IPv6 Wow

Nathan Ward nanog at daork.net
Sun Oct 12 22:05:01 UTC 2008

On 13/10/2008, at 9:53 AM, Stephen Sprunk wrote:

> Mikael Abrahamsson wrote:
>> This brings up an interesting question, should we stop announcing  
>> our 6to4 relays outside of Europe? Is there consensus in the  
>> business how this should be done? I have heard opinions both ways.
> I can understand why some folks would say stop, but unfortunately  
> Europe has the closest public 6to4 relays to the US, and our own  
> providers don't seem to want to put any up.  That means 6to4 will  
> break for a great many folks who _are_ trying to use IPv6 (like  
> developers trying to get ahead of the curve and make sure their apps  
> don't break when the transition finally happens) but whose providers  
> haven't clued in yet.

I'm sure I sound like a broken record to some, but whenever I see  
these comments I feel the need to step up and correct them, until I  
don't see them anymore.

By far the biggest end users of IPv6 are non-experimenters. Real end  
users, many of whom do not know what an IP address is.

6to4 is enabled by default in Vista - any Vista machine with a non- 
RFC1918 address will use 6to4. It is also available in some linksys  
routers, and is enabled by default in Apple Airport Extreme.

> (My traceroutes to have a next-to-last hop in Amsterdam,  
> and I'm on one of the largest ISPs in the US, which apparently  
> hasn't figured out 6to4, much less native IPv6.)

There are public 6to4 relays in the US, I guess your provider just has  
a shorter ASPATH to somewhere in Europe. Unfortunately BGP had no idea  
of geography :-)

Re. whether to advertise outside your continent, it really depends  
whether you're trying to achieve 'good enough' connectivity for 100%  
of people, or really good connectivity for 95% of people.

Perhaps a good way to do it is advertise outside Europe, but have the  
providers that get your advertisement out there prepend their AS a few  
times as it leaves. That way, US providers will still prefer US 6to4  
relays (ie lower latency) but any who don't get a route  
from the US will us your relay in Europe. Kinda gets you best of both  

Nathan Ward

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