Margaret Wasserman wrote: > Hi Tony, > > At 02:47 PM 10/28/02, Tony Hain wrote: > >I have a basic problem with this thread. We have a few people > >discussing fundamental changes in close to a vacuum. > > Obviously, a few people can't make a fundamental change to > IPv6. But, we can propose a change, and discuss it on the WG > (which should not resemble a vacuum). > > >The whole idea that SL should be revoked if a global is available is > >bogus. It is certainly reasonable for the manufacturer of light > >switches to only support SL/LL rather than potentially > multiple global > >prefixes. > > What would a light switch do differently to support > site-local as opposed to global? It still needs to get a > prefix from a router and combine it with an IID using address > autoconf. So, I don't understand what system requirements > could be eliminated by refusing to support global prefixes.
There is no difference in a SL vs. global prefix in the process of address creation in the stack. The real difference is that the simple device frequently is concerned about memory consumption, and that is minimized when it only has to support one SL & LL. The light switch could have a simple policy that the only prefix in the RA that it looks for is SL, which would minimize the management and make it more plug-n-play. I am not claiming I know of devices that look like this, but the opportunity exists the way things are currently defined. If there are multi-party applications that can't deal with scope boundaries, they are aware of that limitation and should be provided a mechanism to tell the stack SL is not an option for this socket. My real problem is that the thread is about preventing or restricting any use of the address format, simply because there is one valid case where it is not a good choice. The fact that there are other cases which are valid is being ignored. If someone wants to write a BCP that says SL should not be used for multi-party apps, fine, but this doc should not go further because other uses do not share the problem. Tony > > I've spent much of the last 7+ years working on IPv6 stacks > for embedded systems, and they have all supported global addressing. > > Margaret > > -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
