Hi Brian, You wrote:
> It's become fashionable to assert that host based solutions > are undeployable. I would like to recall that the model for > rolling out shim6 is very clear - in MS-talk it's called > "Updates are ready for your computer" - since *all* it requires > is an IP stack upgrade. There are absolutely no changes for upper > layers (except maybe a small tweak for SCTP code) and absolutely > no changes for routers or ISPs. Of course, it's true that shim6 > is not much use until a critical mass of users have installed > that update, and it doesn't include TE features for ISPs. > But the deployment model is o(OS programmers) in terms of > significant cost. This only works for that subset of devices for which the operating system is actively maintained and upgraded, for which the programmers invest in adding SHIM6, for which automatic updates are possible and for which the end-user of each device enables such automatic updates. This rules out older desktop and server operating systems, printers, networking gear (Wi-Fi etc.), NAS boxes, probably lots of hand-held devices which only have expensive mobile links to the Net and are not so suitable for automatic OS updates etc. I don't see how this is a viable method of achieving the critical mass required for multihoming based on SHIM6 to become useful. Multihoming 10%, 50% or probably anything less than 95% of traffic does not strike me as useful. Multihoming is only of value when it works for essentially all traffic. For this reason, I think it would be impossible to successfully introduce a host-based approach to multihoming - except perhaps over a period of 15 years or so. There are so many devices which would never be upgraded that it would take years - maybe a decade or more - before they were thrown away and replaced by something modern with the new system built in, that the people who did install the system on all their hosts had 95% or more of their traffic properly multihomed with the new system. Until that level is reached, there are only costs and risks in installing the new system. There is no substantial benefit until 95%, 99% or whatever of the other hosts in the world have been upgraded too. > It's clear that once you ask for action by application > programmers or non-routine action by end users, the costs > become unthinkable. Yes. That is why I think trying to introduce a host-based scalable routing solution is a non-starter. SHIM6 is not regarded as a solution, and the only potentially viable host-based solutions require changes to applications too, so they all use a new hostname-based API. I think that LISP, APT, Ivip, TRRP and Six/One Router are all based on the belief that a host-based solution is not the way to go. There are other, more fundamental, problems with a host-based scalable routing solution - even if there was no problem introducing it. I will write more about these in another message. - Robin _______________________________________________ rrg mailing list [email protected] https://www.irtf.org/mailman/listinfo/rrg
