Le 2012-03-15 à 11:40, Maoke a écrit : > > > 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?
Just referring to: DS-RFC6145-host --(v4net) -- NAPT64 -- IPv4 Internet Is this excluded? RD > > 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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