RE: draft-durand-dual-stack-lite

["Dan Wing" <dwing@cisco.com>]

> -----Original Message-----
> From: owner-v6ops@ops.ietf.org 
> [mailto:owner-v6ops@ops.ietf.org] On Behalf Of ericlklein@softhome.net
> Sent: Thursday, September 18, 2008 11:32 AM
> To: v6ops@ops.ietf.org
> Subject: Re: draft-durand-dual-stack-lite
> 
> 
> Why is/was this being move from V6OPS to Softwire? 

As a general rule, the operations area doesn't work on protocols (v6ops is in
the operations area), and Softwires is trying to re-charter to take the work,
http://www.ietf.org/mail-archive/web/ietf-announce/current/msg05200.html

-d



> Re: draft-durand-dual-stack-lite 
> 
>    * To: james woodyatt <jhw@apple.com>, IPv6 Operations 
> <v6ops@ops.ietf.org>
>    * Subject: Re: draft-durand-dual-stack-lite
>    * From: Alain Durand <alain_durand@cable.comcast.com>
>    * Date: Wed, 30 Jul 2008 18:43:11 +0100
>    * In-reply-to: <E7A64B56-A32B-4186-8453-0BF6AEB8744C@apple.com>
>    * User-agent: Microsoft-Entourage/12.11.0.080522 
> 
> James, 
> 
> Thank you very much for those very good comments. Many of 
> them have been
> discussed during this week, either privately or during one of 
> the meetings.
> We are going to merge the dual-stack-lite and SNAT drafts in 
> the softwire wg
> and we will include text to address those points. 
> 
>  - Alain. 
> 
> 
> On 7/30/08 6:12 PM, "james woodyatt" <jhw@apple.com> wrote: 
> 
> > everyone-- 
> > 
> > This draft describes a scenario where the public IPv4 address mapped
> > to any particular CPE host is assigned to a carrier-grade NAT device
> > located in the service provider network.  To that end, I'd 
> like to see
> > more text that talks about port-mapping protocols like UPnP IGD and
> > NAT-PMP than simply a naked statement that they "may or may not be
> > supported" by the NAT. 
> > 
> > If these protocols are to be supported by a NAT located in 
> the service
> > provider network, regardless of whether the dual-stack-lite
> > architecture is used vs. the multiple-layers of NAT, there is the
> > issue that NAT-PMP and/or UPnP needs to be proxied by the local CPE
> > gateway on behalf of the NAT. 
> > 
> > This is where the dual-stack-lite architecture may be inferior to
> > multiple-layers of NAT, but it's not clear from the draft.  Let me
> > explain... 
> > 
> > In the dual-stack-lite architecture, it's not clear to me 
> that all the
> > IPv4 hosts behind the CPE router-- using RFC1918 addresses, which I
> > hesitate to call private addresses because they are *not* private in
> > this architecture-- will be assigned NAT mappings for the 
> same public
> > IPv4 address.  If they do not, then NAT-PMP cannot be proxied by the
> > CPE router.  The reason is that the single public IPv4 
> address used by
> > the NAT-PMP server is multicast in the announcement packets 
> to all the
> > hosts in the RFC 1918 subnet. 
> > 
> > This deficiency in the dual-stack-lite architecture could 
> be addressed
> > by making an explicit guarantee that all the nodes behind a single
> > IPv6 tunnel to the NAT will be mapped to a single public 
> IPv4 address. 
> > 
> > I also have concerns about hairpinning in the dual-stack-lite
> > architecture.  Not only must the NAT exhibit proper hairpinning
> > behavior, it must hairpin properly between multiple overlapping
> > customer address realms.  I see no mention of hairpinning at all in
> > this draft.  If it's out of scope, I'd like to see a 
> reference to the
> > documents for which it *is* in scope. 
> > 
> > 
> > --
> > james woodyatt <jhw@apple.com>
> > member of technical staff, communications engineering 
> > 
>