Re: [Softwires] MAP and 4rd - Relationship with Single translation

[Rémi Després <[e-mail]>]

Hi Xing,

Le 2012-03-09 à 08:17, Xing Li a écrit :

> Hi, Remi,
> 
> 于 2012/2/10 18:23, Rémi Després 写道:
>> 
>> Hi Xing,
>> Good to have you coming in the (unfinished) technical analysis.
>> 
>> I answered to Ole on his remarks, which you support, but not on the following:
>> 
>> You propose to have a line on "IPv4 to IPv6 communication (single translation) supported", wit 

>> Let me therefore reiterate the wish to see an ISP use case, with its Mapping rules, and with IPv6 prefixes of CEs that illustrate the problem you see.
> 
> The CERNET2 is an IPv6-only core network. We provide stateless IPv4/IPv6 translation between CERNET2 and the IPv4 core network (CERNET). The users can either use single translation directly, or add their own IPv4/IPv6 translor if double translation is required. 
> 
> Is this answer your question?

Not quite, since neither example MAP-T Mapping rules nor assigned IPv6 prefixes are provided, but that may be sufficient so far.

 A key point is that 4rd doesn't prevent a 4rd-capable dual-stack CE node, when it receives no 4rd mapping rule, to exercise single translation. 
 Actually, I believe that using for this the BIH of RFC6535 is both sufficient and recommendable.
 Translated IPv4 packets, because they are sent from CE nodes to DNS64 synthesized addresses, are appropriately routed to their destinations. (It can be via the NAT64-CGN if needed, or via more direct paths if possible.)
Anything missed?

Regards,
RD





> Regards,
> 
> xing
> 
> 
>> 
>> Regards,
>> RD
>>  
>> 
>> 
>> 
>> 
>> Le 2012-02-10 à 04:28, Xing Li a écrit :
>> ... | | | | |
>>>>>   |  5 | IPv6 web caches work for IPv4        |  Y  |  N  |  Y  |  N  |
>>>>>   |    | packets                              |     |     |     |     |
>>>> suggest you rename to "IPv4 to IPv6 communication (single translation) supported"
>>>> 
>>> 
>>> (2) More clarification should be added here. I am not sure 4rd-H can support single translation.
>>> 
>>> (a) According to (1), 4rd-H does not perform header translation defined by RFC6145. 
>>> 
>>> (b) In the softwire mailing list, it seems that 4rd-H cannot support single translation.  See the thread containing http://www.ietf.org/mail-archive/web/softwires/current/msg03324.html                 and other posts.
>>> 
>>> (c) If 4rd-H cannot support single translation, then "IPv6 web caches work for IPv4 packets" requires special configurations, it cannot do IPv6 web caches for non 4rd-H packets.
>> 
>> ...
>> 
>>> (5) I would like to see the details of how 4rd-H handles ICMP and ICMP error messages. In the softwire mailing list there were some discussions. See the thread containing http://www.ietf.org/mail-archive/web/softwires/current/msg03324.html and other posts. Please add
>>> 
>>>  | 17 | Handle ICMP (RFC6145) | Y | n/a | ? | ? |
>> ...
>> 
>