Le 2012-02-02 à 11:59, Maoke a écrit : > dear Remi, > > sorry but your change of the title of this thread is misleading. i mean: no > change to RFC6145 needed for practice of operation. my observation on the > ICMP transparency of RFC6145 in double translation is relatively independent, > without much relationship to 4rd-U.
> well, the only connection is: 4rd-U REQUIRES IPv6 carrying ICMPv4 messages > without translation. 4rd-U is indeed proposed with all IPv4 payloads transparently transmitted, including ICMPv4. This could be changed if ICMPv4 if there would be a convincing need. Honestly, what you have provided so far hasn't been convincing. > 2012/2/2 Rémi Després <[email protected]> > > Le 2012-02-01 à 03:04, Maoke a écrit : >> ... >> >> i have investigated, technically, what if we had updated RFC6145 with >> carrying ICMPv4 messages in IPv6 directly instead of translating to ICMPv6, >> specially for double translation, > > Introducing ICMPv4 messages in IPv6 packets "instead of" ICMPv6 messages in > RFC6145 would be an incompatible change. > I don't think anyone proposed that. > > What might be envisaged without the same backward incompatibility, is that > IPv6-only hosts would accept in IPv6 packets BOTH IPv6 ICMP messages and > ICMPv4 messages. > > Yet, it remains to be analyzed whether it would be useful in real world. > > This depends on a detailed use case being identified, where double RFC6145 > translation would have a substantial advantage over the header-mapping > variant of 4rd-U-03 (4rd-H). (This advantage would have to compensate for the > loss of IPv4 transparency as good as that of 4rd-E, and for the loss of the > tunnel-specific traffic class which can be used in 4rd-E.) > > This use case, key for this discussion, is subject of another e-mail thread. > > i (and others) have tested the single/double-compatibility in practice and > confirmed it is useful at least for some users. I don't deny. I just believe that, to have a chance to be convinced, I need a description of at least a use case where it is useful (with applicable mapping rules and indication of whether there is a DNS64). > another mail thread might fall into pure philosophical debate, which is not > preferred, Whatever the thread, I look for a technical discussion, not a philosophical one. RD > > > - maoke > > > RD >
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