Le 2012-03-15 à 14:52, Maoke a écrit : > > > 2012/3/15 Rémi Després <[email protected]> > > 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 > > > what is RFC6145-host??
E.g. a host with BIH (RFC6535) or with 464XLAT, i.e. one that supports IPv4 applications and is attached to an IPv6-only network. Clear enough? > (seeing you have corrected the v4net with v6net) if it is a host connected to > an IPv6 network, it is the case of single NAT64, where we have the problem of > "interwork"? See above. RD > > - maoke > > > > 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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