Microsoft: Give Xbox One users IPv6 connectivity

Geoff Huston gih at
Thu Oct 10 05:19:09 CEST 2013

Hi Chris,

On 10/10/2013, at 12:22 PM, Christopher Palmer <Christopher.Palmer at> wrote:

> I appreciate the enthusiasm :).  
> As a general principal, providing native IPv6 to the end-user device will reduce the support cost to a network operator - because gamers do call their ISP if they can't get things working.
> There are some network effects that complicate the story. Inevitably we have to use Teredo for lots of P2P, because IPv6 is so rare. You might have IPv6, but if your peer doesn't - alas. Also, address selection is sensitive to policy that we'll be tuning as the Xbox One launch progresses.
> Separate from the reliability, complexity, and troubleshooting costs of IPv4 P2P - native IPv6 gives you a significant increase in effective bandwidth if utilized, because we drop the IPv4 and UDP header for Teredo. 
> We're really hoping to see more network operators follow the lead of Comcast, Free, Google Fiber, others - and push IPv6 into the residential market.
> More technical details, (but less pictures) are at

In considering the currently observed 35% Teredo connection establishment failure rate that we discussed at NANOG this afternoon, you also pointed out that it would all be teredo peer to peer, and yes, when its all teredo to teredo it becomes V4 to V4 peer to peer and the factor of Teredo relays is less prominent.

But I've thought about your response, and if I'm allowed to dream (!), and in that dream where the efforts of COmcast, Google etc with IPv6 bear fruit, and I'm allowed to contemplate a world of, say, 33% IPv6 and 66% V4, then wouldn't we then see the remaining Teredo folk having 33% of their peer sessions head into Teredo relays to get to those 33% who are using unicast IPv6? And wouldn't that require these Teredo relays that we all know have been such a performance headache?

I applaud what you guys are doing, really, but from my perspective it looks like the reliance on Teredo is really quite scary given what we see out there about how it behaves, and I'm kinda wondering what I'm missing here that you obviously must've thought through in justifying this product decision! 



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