RE: NAT-PT Applicabilty for 3GPP

[Suresh Satapati <satapati@cisco.com>]

Karim,

This may be redundant to you, but to seek WG opinion I will repeat the
argument here on this list.

> I brought up the same issue during the DT work and agree with Randy's
> point that if a scenario exists that requires a subset of NAT-PT (i.e. 3GPP
> IMS) then it does not necessarily imply that NAT-PT as specified in RFC 2766
> is applicable. The draft could however point out which parts of NAT-PT are
> applicable in this case.
>
> Regarding the actual SIP solution there is a reference in 3gpp-analysis-07
> to draft-elmalki-sipping-3gpp-translator-00. Following Margaret's comments
> last time and the recommendation in draft-ietf-3gpp-analysis it is on the
> SIPPING agenda this time. For those who may be interested here's a new version
> of the draft:
> http://standards.ericsson.net/karim/draft-elmalki-sipping-3gpp-translator-00.txt
>

This whole "subset applicability" argument stems from incorrect assumption that
NAT-PT (RFC 2766) mandates DNS-ALG.

In the past for v4 land, ALGs have been specified in separate documents.
For e.g. RFC 2663/3022 clearly defines the role of "NAT", and for
DNS-ALG there is RFC 2694.

RFC2766 mentions DNS-ALG (and FTP-ALG) as an example, in addition to
basic NAT-PT operation. There is no text that states NAT-PT mandates
DNS-ALG.

This clarification came from the author of NAT-PT, as well. Pls refer to
previous posting:

http://ops.ietf.org/lists/v6ops/v6ops.2003/msg01460.html


>
>  > -----Original Message-----
>  > From: owner-v6ops@ops.ietf.org [mailto:owner-v6ops@ops.ietf.org]On
>  > Behalf Of Randy Bush
>  > Sent: den 13 november 2003 00:25
>  > To: Suresh Satapati
>  > Cc: v6ops@ops.ietf.org
>  > Subject: Re: NAT-PT Applicabilty for 3GPP
>  >
>  >
>  > > In the above, though a SIP-specific translation mechanism is being
>  > > recommended, I do not see how the recommended solution will be
>  > > fundamentally different from NAT-PT. In this sense, the
>  > applicability
>  > > of NAT-PT is still valid.
>  >
>  > if A is a proper subset of B, a need for A does not mandate B,
>  > especially if A is a very localized hack and B is global, generic,
>  > and questionable.
>  >
>  > randy
>  >
>  >
>