Below, in-line

Regards,

Jordi

 

 

 

De: Lee Howard <[email protected]>
Responder a: IPv6 in Africa Discussions <[email protected]>
Fecha: lunes, 11 de marzo de 2019, 19:58
Para: <[email protected]>
Asunto: Re: [AfrIPv6-Discuss] AfrIPv6-Discuss Digest, Vol 149, Issue 1

 

 

On 3/11/19 2:17 PM, JORDI PALET MARTINEZ via AfrIPv6-Discuss wrote:

Responding below, in-line, and numbered the cases.

 

I think I’m right, but happy to discuss/clarify!


Regards,

Jordi

 

 

 

De: Lee Howard <[email protected]>
Responder a: IPv6 in Africa Discussions <[email protected]>
Fecha: lunes, 11 de marzo de 2019, 19:03
Para: <[email protected]>
Asunto: Re: [AfrIPv6-Discuss] AfrIPv6-Discuss Digest, Vol 149, Issue 1

 

1)      If it is an IPv6 flow, it does not use the CLAT function in the 
handset. It might use a NAT64 function at the provider edge.

Let’s say if the source app is IPv6, using DNS64, it will be an IPv6-only flow 
in the operator network and the NAT64 will be used only if the destination is 
IPv4-only.

Yes, the phone will use IPv6, because the name server will only return a AAAA; 
the app will never see an IPv4 DNS response.


2)      If it is an IPv4 flow, the handset translates from IPv4 to IPv6 (the 
CLAT function). My guess - and it's only speculation - is that the handset 
takes a few milliseconds to do this for each packet. The flow might also use a 
NAT64 function at the provider edge.

If the source app is IPv4-only, the CLAT will do stateless NAT46 (how this is 
done may depend on the implementation). If it is done “full stateless” I guess 
is much faster than a NAT44 then a NAT46.

When would a handset do NAT44? 

There are good and bad CLAT implementations. The bad ones instead of doing 
stateless NAT46 do a stateful NAT44 than stateless NAT46 …

In a native dual-stack network, or native IPv4-only network, the handset never 
translates. In a 464xlat network, the handset translates to IPv6 if the app 
uses IPv4 literals or expects IPv4. In Apple handsets, this doesn't happen 
because all apps are required to support IPv6 (with NAT64).

In this case, it will always use NAT64, unless we work on this (case for 
IPv4-only SmartTVs):

https://datatracker.ietf.org/doc/draft-palet-v6ops-464xlat-opt-cdn-caches/?include_text=1

If we work on solving this issue, the NAT64 doesn’t need to be used! And is not 
too complex, I think … EAMT already exist for that.

We should discuss that on v6ops. My initial reaction is that I'm tired of new 
transition technologies. Let it go, IPv4 will never be as good as native 
connectivity.

Is nothing new is is just an operations practice for CDNs (they do for 
100.64/10 when there is CGN). Is just making sure that the CLAT implementation 
follows the SHOULD for supporting EAMT as indicated in the SIIT RFC … long 
history but yes, it is v6ops.

I also don't like the fact that rich CDNs already have preferential placement 
inside carriers' networks; if they want better connectivity, they should run 
IPv6, not expect the ISP to do translation for them.

The CDNs are dual-stack today. The problem is not at the CDN, is at the SmartTV 
which is IPv4-only.

Pushing more work onto the handset is the wrong direction. Work needs to be 
done on devices with big CPUs and connected power supplies.

Agree, as said this case is basically for CEs because there are IPv4-only STBs 
and SmartTVs … it may apply also to a handset with a broken app, but I don’t 
think it is the case anymore today.

3)      If it was an IPv4-only network or dual-stack network, there's no CLAT, 
only NAT at the provider edge.

Depends on the deployment model. It may be only NAT at the CPE, or NAT at the 
CPE and CGN, so we have NAT444 …

Yes, you're right, I was thinking about mobile networks.


But in this case (3), if the destination is an IPv6-only datacenter (Facebook 
is a simple example), you have also NAT446 at the datacenter … (it may be just 
NAT46). There are different ways to do SIIT-DC or other equivalent solutions.

Yes, also agreed. A residential network with NAT44 on the home router, CGN44 in 
the ISP, going to NAT46 at Facebook is NAT4446. 

Lee


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