Subject: Re: 3gpp-analisys-05 : UE Connecting to a Node in an IPv4 Network through IMS

From: Pekka Savola <[email-masked]>
Date: Fri, 19 Sep 2003 14:59:40 +0300 (EEST)

On Fri, 19 Sep 2003, BAUDOT Alain FTRD/DMI/CAE wrote:
> The section 4.1 is stating "There will probably be few legacy IPv4 nodes
> in the Internet that will communicate with the IMS UEs" This is a rather
> strong assumption, and I guess it is difficult today to have clear idea
> on how much probable it is. My comment is just that the reader may be
> confused by this statement assuming that it is most probable while it is
> not. 

I kind of agree, it may be difficult to estimate it.  Perhaps making the 
statement more vague could help, e.g. change:

    There will probably be few legacy IPv4 nodes in the Internet that
    will communicate with the IMS UEs. It is assumed that the solution
    described here is used for limited cases, in which communications
    with a small number of legacy IPv4 SIP equipment are needed. [...]

to something like:

    The first priority is to upgrade the legacy IPv4 nodes to dual-stack, 
    eliminating this particular problem in that specific deployment.

    Still, it is difficult to estimate how many non-upgradeable legacy 
    IPv4 nodes need to communicate with the IMS UEs.  It is assumed 
    that the solution described here is used for limited cases, in which 
    communications with a small number of legacy IPv4 SIP equipment are 
    needed. [...]

> So, maybe this section would only state that the identified
> solution based on NAT-PT may apply within the scope of few simultaneous
> cases, and that other more scalable solutions are relevant to the SIP
> WG.

If you read the draft so that it identifies a solution building on NAT-PT, 
the draft likely needs to be clarified slightly.

The way I read it says that a new SIP-specific translation mechanism needs
to be specified, which could e.g. re-use limited subsets of NAT-PT.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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From: "BAUDOT Alain FTRD/DMI/CAE" <[email-masked]>
Date: Fri, 19 Sep 2003 11:03:26 +0200

Hi,

The section 4.1 is stating "There will probably be few legacy IPv4 nodes in the Internet that will communicate with the IMS UEs"
This is a rather strong assumption, and I guess it is difficult today to have clear idea on how much probable it is.
My comment is just that the reader may be confused by this statement assuming that it is most probable while it is not.
So, maybe this section would only state that the identified solution based on NAT-PT may apply within the scope of few simultaneous cases, and that other more scalable solutions are relevant to the SIP WG.

Regards, 
Alain.
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Alain Baudot
France Telecom R&D
FTR&D/DMI/SIR/IPI        e-mail : [email-masked]
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