Re: implications of 6to4 for v6coex

[james woodyatt <jhw@apple.com>]

On Sep 16, 2008, at 18:39, Joe Abley wrote:
> Perhaps you're asking the wrong question. Perhaps there's no reason  
> for any operator not to deploy a 6to4 relay for use of their  
> customers; perhaps the problem instead is that there is no clear  
> reason in the eyes of those operators to bother.
> Does it make the helpdesk phone ring less? Will it cause an average  
> ISP to win more customers this month? I suspect the pragmatic answer  
> to both is no.
Sigh.  Again, here are the incentives providers have today for  
deploying 6to4 and Teredo relays:
+ To prevent P2P traffic between their customers using 6to4 at  
2002::/16 and Teredo at 2001::/32 from having to be forwarded out of  
their networks for disinterested 3rd parties to relay on their behalf.  
Even for *IPv4-only* service providers, this either A) costs money for  
traffic across their borders that would otherwise not need to be  
carried (when the 3rd party relays are working), or B) prevents their  
IPv4 customers electing to use different IPv6-transition mechanisms on  
their own from communicating with one another (when the 3rd party  
relays are refusing to serve) and drives customers away to other  
providers where the relay service is reliable.
+ To wrest the control over the quality of service for their native- 
IPv6 customers communicating with 2002::/16 and 2001::/32 destinations  
on the public Internet away from the disinterested (and potentially  
hostile) 3rd parties who operate the relays advertised to them.
Despite these incentives, service providers are balking at deploying  
relays, and not merely for financial and practical reasons.  Some have  
privately told me their technical objections to the standards  
themselves, which I have tried to relate here.  (Sadly, the V6OPS  
minutes from the Philadelphia and Dublin meetings don't seem to be  
posted where I can find them, otherwise I would link to where I  
remember Alain Durand's remarks in the V6OPS session about how private  
6to4 and Teredo relays cannot be deployed in a practical fashion.)
No, I don't imagine that 6to4 and Teredo traffic *currently* costs  
many providers enough money, or lost business, or help desk calls to  
justify the expense of deploying the relays (though, with the recent  
release of uTorrent 1.8, I suspect that may change).  However, some  
providers certainly *do* have technical objections.

--
james woodyatt <jhw@apple.com>
member of technical staff, communications engineering