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

["Karim El-Malki (HF/EAB)" <karim.el-malki@ericsson.com>]

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