Subject: Re: (ngtrans) back to back

From: Brian E Carpenter <[email-masked]>
Date: Tue, 31 Oct 2000 14:39:24 -0600

Since I didn't see anyone else respond, let me try an IMHO response.

Randy Bush wrote:
> 
> say a provider manages to turn on native ipv6 on an entire large backbone,
> so it is running native v4 and native v6.
> 
>   o please describe the gating/translation for a native v6 flow from a v6
>     customer to a customer of one of the backbone's peers where that peer
>     backbone has not put up native v6.

Is the peer customer a v6 user or a v4 user?

1. V6 user - the first provider will have to offer a tunnel endpoint (or a 6to4 relay,
   which is a similar beast). In either case the remote v6 user has to find it
   (tunnel broker or v4 anycast, or manual config).

2. V4 user - run an application level relay or a NAT/PT box. Ugly? Yes.

> 
>   o please describe where the v4 packts a v4 customer of this backbone are
>     gated/ translated when they want to talk to a v6-native on the same
>     backbone.

Same as 2. above.

Lots of details to be worked.

  Brian

---

From: Randy Bush <[email-masked]>
Date: Wed, 01 Nov 2000 07:51:28 -0800

> Is the peer customer a v6 user or a v4 user?

both cases are important

> 1. V6 user - the first provider will have to offer a tunnel endpoint (or a
>    6to4 relay, which is a similar beast). In either case the remote v6
>    user has to find it (tunnel broker or v4 anycast, or manual config).

this is going to scale?  we're talking about large-scale deployment here.

> 2. V4 user - run an application level relay or a NAT/PT box. Ugly? Yes.

no worse, impossible.  how would the v4 target even know that a v6 host was
trying to reach them?

> Lots of details to be worked.

seems like it.  and seems as, if v6 is to be actually deployed, there needs
to be a real solution set here.

randy

---

From: Brian E Carpenter <[email-masked]>
Date: Thu, 02 Nov 2000 13:42:13 -0600

> this is going to scale?  we're talking about large-scale deployment here.

For the 6to4 model, Tony Hain's draft addresses the scaling problem.
I don't think that the tunnel broker really scales as it is though;
some kind of anycast mechanism to find a tunnel end point does seem
to be required. In both cases, this seems to imply that I6SPs will be
operating large numbers of 6to4 relays and/or tunnel end points.

> no worse, impossible.  how would the v4 target even know that a v6 host was

It wouldn't. It would believe that a v4 host was trying to reach it. Not really
any different from today, when the client is NATted or using an HTTP proxy.
It's because this is ugly that we went for the dual stack model in the first
place, but it looks like we will have to deal with this case anyway, with
3rd generation mobiles.

    Brian

-- 
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Brian E Carpenter 
Program Director, Internet Standards & Technology, IBM 
On assignment for IBM at http://www.iCAIR.org 
Board Chairman, Internet Society http://www.isoc.org
Non-IBM email: [email-masked]