On Aug 19, 2011, at 1:08 PM, Rémi Després wrote: > > Le 19 août 2011 à 17:11, Mark Townsley a écrit : > >> >> On Aug 19, 2011, at 5:17 AM, Rémi Després wrote: >> >>> Also, one of his slides has "4rd aka Stateless DS-lite". He knows, as you >>> know, that I had expressed strong opposition to this badly reductive view >>> (DS lite is hub and spoke, has no NAT in CPE's, ...). >> >> Let me fill you in on some history. >> >> The term "Dual Stack Lite" came into being during a discussion at a cafe >> between Alain Durand and I. It was June 2008, and Alain was in Paris for the >> ICANN meeting while still working for Comcast. We had been discussing the >> various pros and cons of tunneling vs. dual-translation for a while. Alain >> was emphasizing that what was of most importance to him as an ISP, was that >> he not be burdened with provisioning IPv4 within the ISP network itself. >> However, in all cases the service to the subscriber was intended to be >> dual-stack. So: "Dual-stack" service but "lighter" on the ISP in terms of >> management and provisioning. Thus the term "dual-stack lite" was born. > > That's a good clarification. > > But in the mean time, DS-lite got specified in an RFC that won't change.
But RFC's get updated all the time, as does terminology. Adding an adjective to something that is well understood to indicate that it can serve the same purpose but in a different way is quite useful during the introduction of that technology. Think "Horseless Carriage" http://en.wikipedia.org/wiki/Retronym A retronym is a type of neologism that provides a new name for an object or concept to differentiate the original form or version of it from a more recent form or version.[1] The original name is most often augmented with an adjective (rather than being completely displaced) to account for later developments of the object or concept itself. Much retronymy is driven by advances in technology. - Mark > RFC6333 says: > - "Dual-Stack Lite enables a broadband service provider to share IPv4 > addresses among customers by combining two well-known technologies: IP in IP > (IPv4-in-IPv6) and Network Address Translation (NAT)." > - "the Dual-Stack Lite model is built on IPv4-in-IPv6 tunnels to cross the > network to reach a carrier-grade IPv4-IPv4 NAT (the AFTR)," > - etc. > >> From the beginning the "lite" term was about having less IPv4 in the access >> network for the operator to manage and provision, while still providing >> dual-stack service to the subscriber. 4rd fits that, as does RFC 6333. The >> solution details are just that - details. > > The devil is in details. > > Too bad 4rd wasn't invented before DS-lite. It would have better deserved the > "lite" qualifier, but that's not how things happened. > > Because of what RFC6333 says, suggesting NOW that solutions that don't need > NATs are variants of DS-lite is a sure way to confuse people. > > I do hope this discussion will now stop: there are so many technical > "details" that need to reach common understanding, and agreement. > In any case thank you for the really interesting explanation on history. > > Cheers. > RD > >
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