Alain Durand wrote: > > 100% agreed. Still, we have to pick a default. > My point is that I'd rather like the default case to be that apps that > require global addresses don't have anything special to do to work.
I prefer the behaviour specified by default address selection - pick the smallest 'scope' which matches unless the application has a good reason to do otherwise. Stability aside, the 'smallest matching scope' rule only fails for applications that forward addresses out-of-scope. In this case, either: - forward names, so that you get all in-scope options, not just the one that worked for the forwarder. - accept that your application is now delving into the routing space and code accordingly. The other way of looking at it is to observe that 'local' addresses are proposed as a solution for when 'global' addresses are unavailable, unstable, or otherwise untrusted. In other words, if local addresses exist the general assumption should be that the network wants applications to prefer them over global ones. I cannot think of an example for a non-forwarding connection where this would not be true. Note: 'prefer' is qualified by the source address selection rules, which will (among other things) prefer (in order): - matching scopes over non-matching - smaller scopes over larger - longest prefix match In a multi-addressing environment, applications must be ready to try multiple source-destination address pairs until one succeeds. A source address selection compliant gethostbyname will return the destinations in preferred order (taking into account available source addresses). There is an implementation question on what order the two dimensional destination and source space should be searched. -- Andrew White [EMAIL PROTECTED] -------------------------------------------------------------------- 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] --------------------------------------------------------------------
