Re: comments on draft-durand-v6ops-assisted-tunneling-requirements-00 .txt

[Marc Blanchet <Marc.Blanchet@hexago.com>]

Karim,
 "dumb questions":
- NAT were not planned to happen. IPv4 was not designed with NAT. NAT
happened. Nobody can control the deployment of NATs.
- now, when you say: 
 + "the customer does not have a NAT in the customer equipment", how can we
enforce/ensure that this will never happen?  

It appears to me that NATs are everywhere, even in places that tried to
avoid them.(The world's richest organisation in terms of IPv4 addresses
have so many NATs you can't think of...). And you can't restrict the
deployment of NAT: the operator of a network (3G, wireless, wired, etc...)
may deploy a NAT as its own way. How would 3G be able to enforce the
non-existence of NATs?

Does the assumption of no-NAT really stand?

excuse-me if these are dumb questions.

Marc.

-- Wednesday, April 14, 2004 21:37:27 +0200 "Karim El-Malki (HF/EAB)"
<karim.el-malki@ericsson.com> wrote/a ecrit:

> Hi
> 
> I have some comments on the draft. Section 2 says:
> 
>   - The customer configuration may be diverse, and not necessarily
>        predictable by the ISP. The following cases must be supported:
>          - a single node,
>          - a leaf network,
>          - using a globally routable IPv4 address,
>          - behind a NAT,
> 
> However it also says (later in section 2):
> 
>    Althought the main focus of this document is the ISP scenario,
>    assisted tunneling is applicable in all the other scenarios:
>    unmanaged, enterprise and 3GPP.
>    ...
>    In 3GPP networks, assisted tunneling can be used in the context of
>    dual stack UE connecting to IPv6 nodes through a 3GPP network that
>    only supports IPv4 PDP contexts [3GPP, 3.1].
> 
> There seems to be a contradiction when considering 3GPP networks,
> since the customer does not have a NAT in the customer equipment
> (i.e. mobile terminal). Therefore the tunneling can be terminated
> within the mobile operator's network and never goes through a NAT.
> That's a good thing since we wouldn't have to pass even more traffic
> (v6 tunnelled traffic) through NATs in this scenario. For the same
> reason the following consideration on ISATAP does not apply to 3GPP
> networks (also described in the draft reference [3GPP]):
> 
>    7.3 ISATAP
> 
>    Similar considerations as Teredo, section 7.2, applies to Isatap.
>    However, as Isatap can not work accross NAT, it is of much less
>    interest in the framework of this document.
> 
> I think that to make this draft applicable to 3GPP networks some
> substantial changes would be needed such as the removal of the NAT
> assumption.
> 
> /Karim
> 



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Marc Blanchet
Hexago
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