In your letter dated Sat, 30 Jul 2011 11:39:53 -0700 you wrote:
6RD is not a last mile solution. With the existing levels of IPv6 traffic, an
ISP would deploy a couple of 6RD relays at their main IX. In a country such as
France, it means that a 6RD customer in Nice would see their IPv6 traffic bei
ng encapsulated all the way to Paris over IPv4 crossing the entire ISP's netwo
rk for some 400 miles. In Spain, the really native part of the traffic would p
ossibly start in Madrid.
Imagine 2 customers in Barcelona, who are with two different ISPs using 6RD. T
he 6RD relays are in Madrid for both, likely not much more than a few miles aw
ay or even possibly in the same IX (I don't know the details of IXes in Madrid
). The 6RD traffic from one goes over IPv4 all the way to Madrid, then goes na
tive for a few miles to the other ISP's 6RD relay, then back over IPv4 to Barc
elona. This is not native.
So, 6rd is bad because it allows an ISP to deploy it in a sub-optimal way.
Wow, if that how we are going to judge protocols then we can just as well go
If the existing levels of IPv6 traffic were a reason to install just one 6rd
box for an entire country then expecting that ISP to deploy native IPv6 would
be extremely unrealistic.
And even if an ISP would do that. The round trip latency between Barcelona and
Madrid is likely to be in the order of 5ms. There are DSL error correcting
settings that have much impact than that.
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