2012/3/15 Rémi Després <[email protected]> > > Le 2012-03-15 à 10:29, Maoke a écrit : > > > > 2012/3/15 Maoke <[email protected]> > >> >> >> 2012/3/15 Rémi Després <[email protected]> >> >>> >>> Le 2012-03-15 à 10:02, Maoke a écrit : >>> >>> >>> >>> 2012/3/15 Rémi Després <[email protected]> >>> >>>> Maoke, >>>> >>>> Let's try, once more, to understand each other. >>>> >>>> If we assume that MAP-T CEs (and BRs) now MUST translate DCCP (which >>>> is AFAIAC a positive result of our discussion): >>>> a) Such a CE can communicate with an IPv6-only host including in DCCP. >>>> b) The same would apply to UDP lite if MAP-T would also require >>>> UDP-lite translation. >>>> c) If a MAP-T CE communicates via a NAT64 (which is based on RFC6145, >>>> i.e. with DCCP optional), DCCP is broken if the NAT64 doesn't translate >>>> DCCP (as permitted by RFC6145). >>>> d) If RFC6146 (NAT64) and/or RFC6145 would be modified to also impose >>>> DCCP translation, nodes complying with modified versions and those >>>> complying with previous versions wouldn't be guaranteed to interwork for >>>> DCCP. >>>> >>>> If we don't agree on this, there is still something to be clarified >>>> between us. >>>> >>> >>> surely do not. RFC6146 clearly states: >>> >>> The current specification only defines how stateful NAT64 translates >>> unicast packets carrying TCP, UDP, and ICMP traffic. Multicast >>> packets and other protocols, including the Stream Control >>> Transmission Protocol (SCTP), the Datagram Congestion Control >>> Protocol (DCCP), and IPsec, are out of the scope of this >>> specification. >>> >>> >>> I said "If RFC614... would be modified to also impose DCCP translation" >>> => I take the point that you are not interested in that, but I don't think >>> there was a contradiction. >>> OK? >>> >> >> it is not yet modified. with the current statement of RFC6146, the >> current equipment doesn't support DCCP. if it is modified, the update may >> state mandatory imposement for DCCP. i don't see any problem here. >> > > more clearly speaking: stateful NAT64, i think, only needs to be done once > in a delivery, therefore either the DCCP is supported or it is not. there's > no "interwork" between NAT64 who has been modified with the NAT64 who has > not. incorrect? > > > The full sentence was: "If RFC6146 (NAT64) and/or RFC6145 would be > modified to also impose DCCP translation, nodes complying with modified > versions and those complying with previous versions wouldn't be guaranteed > to interwork for DCCP." > > I assumed an RFC6145 complying node can talk to a NAT64, right or not? >
you mean the stateful NAT64-ed IPv4 host (let's call it A) having access to an IPv4 host (let's call it B) behind a stateless RFC6145 translator, mapped to IPv4-converted IPv6 address in the IPv6 domain. if so, it is not right that RFC6145 complying node can talk to a NAT64. let's see the details: model: A ---(IPv4 network)--- NAT64 (stateful) ---(IPv6 cloud)--- RFC6145 translator --- B because A would be translated by NAT64 to an arbitrary IPv6 address, A', which is not an IPv4-converted one either in MAP or in RFC6052, the RFC6145 translator cannot handle it statelessly for any end-to-end communication. the box in front of B should be another NAT64, and as i said previously, no problem in interwork. if one NAT64 supports DCCP, it adjusts the checksum; if the other doesn't support, it drops DCCP. no case of asymmetrically processed but end-to-end deliverable DCCP here. - maoke > (A NAT64 talking to another NAT64 was part of what I wrote!!!) > > RD > > > > > >> on the other hand, i cannot understand how the CNP helps stateful >> checksum validity. may you please to clarify? >> >> maoke >> >> >>> >>> RD >>> >>> >>> >>> - maoke >>> >>> >>>> If we agree, I have nothing else on this point. >>>> >>>> Regards, >>>> RD >>>> >>>> >>>> >>>> If, as you suggest, >>>> 2012-03-15 02:04, Maoke: >>>> >>>> 2012/3/14 Rémi Després <[email protected]> >>>> >>>>> >>>>> Le 2012-03-14 à 10:46, Maoke a écrit : >>>>> >>>>> >>>>> 2012/3/14 Rémi Després <[email protected]> >>>>> >>>>> ... >>>> >>>> >>>>>> Changing DCCP support from optional to mandatory in RFC6145 isn't >>>>>> backward compatible (an upgraded node isn't guaranteed to interwork with >>>>>> a >>>>>> non upgraded node). >>>>>> >>>>> >>>>> the CE/BR specified RFC6145-compliant might be a problem but MAP-T is >>>>> still in development. if we state to enforce DCCP mandatorily rather than >>>>> optional in MAP-T, a MAP-T-compliant CE/BR won't has the backward >>>>> compatible problem. to this extend, MAP-T is at the same kick-off line of >>>>> the 4rd-U. >>>>> >>>>> >>>>> 1. I agree that, between CEs and BRs, there can be no problem for DCCP >>>>> (provided the draft is completed to this effect). The comparison table was >>>>> explicitly made with existing drafts, and intended to be updatable. >>>>> >>>>> 2. The MAP-T draft is also claimed to allow "communication between >>>>> IPv4-only, as well as any IPv6 enabled end hosts, to native IPv6-only >>>>> servers in the domain that are using IPv4-mapped IPv6 address". In >>>>> this case, AFAIK, the backward compatibility problem exists >>>>> Thought? >>>>> >>>> >>>> surely it does not exist. that statement applies to the MAP-T-compliant >>>> equipments, when it is used as a IPv4-to-IPv6 single translator or as an >>>> native IPv6 router. same deployment of equipments should support >>>> double-translation, single-translation, and native IPv6 accesses >>>> simultanenously. that's one of the points of the MAP-T. >>>> >>>> - maoke >>>> >>>> >>>>> >>>>> >>>>> To be even more precise, H6 of the comparison table can be: >>>>>> "For ISPs that don't provide all CE nodes, and for shared IPv4 >>>>>> addresses, DCCP and UDP-Lite are supported, as well as future protocols >>>>>> using the TCP checksum algorithm and ports at the same place" >>>>>> >>>>> >>>>> i actually think the original text is fine. "For .... shared IPv4 >>>>> addresses" is not needed for 4rd-U, to my understanding, nor needed to >>>>> MAP-T. >>>>> >>>>> >>>>> Will see what to do, then, when changes to the MAP-T draft concerning >>>>> DCCP are known. >>>>> >>>> >>>>> RD >>>>> >>>>> >>>>> >>>>> >>>>> maoke >>>>> >>>>> >>>>>> >>>>>> Does this cover the point? >>>>>> >>>>>> RD >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> ;-) >>>>>> maoke >>>>>> >>>>>> >>>>>>> >>>>>>> but this is not my point. my point is: there must be something we >>>>>>> don't know ("non omnia possumus omnes"). even we have gone through the >>>>>>> RFCs, there might be some other proprietary L4 protocols, or >>>>>>> experimental >>>>>>> protocols. even they are minority, i don't think ignoring their >>>>>>> existance >>>>>>> in our solution fits the spirit of the Internet. it might be argued that >>>>>>> NAT44 doesn't support such L4 protocols now, but an L4 protocol owner >>>>>>> may >>>>>>> makes his own NAT44, either attached to the CE or separated. if 4rd-U >>>>>>> respects such an effort, it should state "currently blahblabla L4 >>>>>>> protocols >>>>>>> are supported". the similar statement applies to the RFC6145 or MAP as >>>>>>> well. >>>>>>> >>>>>>> >>>>>>> i somehow am hard to accept words like "far fetched theoretical >>>>>>> problem". >>>>>>> >>>>>>> >>>>>>> If I had thought it might be so, I would have avoided the word. >>>>>>> >>>>>>> >>>>>>> the L4-recalculate is a generic, architectural solution, surely >>>>>>> needing codes for every L4 protocol. but this generality in architecture >>>>>>> makes RFC6145 or MAP-T equipment be easily enhanced to support anything >>>>>>> new >>>>>>> with the same logic. but for the 4rd-U BR, it looks to me we cannot have >>>>>>> the unified logic for all (even limited to existing and well-known) L4 >>>>>>> protocols. >>>>>>> >>>>>>> only my 2 cents. >>>>>>> >>>>>>> >>>>>>> With amendments above, the point is AFAIK completely covered: >>>>>>> everything is rigorously true, and worth noting. >>>>>>> Thanks for the useful reference to the RDP of RFC1151. >>>>>>> >>>>>>> RD >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> Softwires mailing list >>>> [email protected] >>>> https://www.ietf.org/mailman/listinfo/softwires >>>> >>>> >>>> >>> >>> >> > >
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