[v6ops] 464XLAT in Multi-interface environments (was: I-D Action: draft-ietf-v6ops-claton-02.txt)

[Philipp Tiesel <[e-mail]>]

Hi,

While reading draft-ietf-v6ops-claton-02, I spottet a little inconsistency that may need to some wider discussion:

> 5. Enabling CLAT
> 
> For performance and security reasons CLAT MUST NOT be enabled if the
> node has IPv4 native connectivity over the given interface.
> Therefore recommendations provided in this section are only
> applicable to an IPv6-only node (a node which does not have a native
> IPv4 default route configured).

There is a subtile difference between 
- a node that has no native IPv4 on a given interface and
- a node that has no a native IPv4 default route  

Let’s consider the following case: I have a node with a 3GPP interface that has a native IPv4 address and no IPv6, e.g., because of data roaming, and a Wifi interface that has no IPv4 address and can be configured for 464XLAT with a NAT64 prefix discovered by PRE64 RA option.

The former definition (no native IPv4 on a given interface) would allow the OS to use 464XLAT on the (most probably preferable) Wifi interface while the latter (no a native IPv4 default route on the node) would not. 

I would suggest either to remove the second sentence from section 5 or add some more detailed discussion on this case (happy to contribute text if requested).

AVE!
   Philipp