Keith's multi-party applications won't work if the parties refer non-global addresses to each other. Margaret recommends that everyone use global addresses, but filter certain prefixes at various administrative boundaries. How, then, do Keith's applications know which addresses have global scope and which do not?
A tacit assumption seems to be that applications will not have to deal with link-local addresses. I'm aware of the recommendation not to place link-local addresses in the DNS, but I know of no prohibition of applications communicating via link-local addresses. If they may do so, is this less problematic than using site-local addresses? Since I know nothing about filtering in routers, can someone tell me why filtering on FEC0::/10 is more complex than filtering on prefixes chosen by the local administrator(s)? And concerning Margaret's point on nesting sites, could routers not filter within FEC0:0:subn:etid::/64 addresses? Again citing the disclaimer re my lack of knowledge, the filtering-on-locally-designated-prefixes method seems unwieldy compared to the filtering-on-well-known-scope method. Implementations can allow an administrator to configure address scope preferences using the well-known scopes. Nodes (applications) on the same subnet could then have addresses of different scopes. This would be cumbersome at best without well-known scopes. Some have complained about the complexity of always disambiguating site-local addresses by means of their zone identifiers. This seems insignificant to me; the same must be done for link-local addresses. The zone identifier accompanies the address wherever it goes. Right? I understand that sites that merge would have to renumber if their subnet IDs conflicted. Some have stated that a disconnected site using site-local addresses must renumber when it connects to the Internet. Wouldn't the site simply add the new prefix(es), and the nodes use the new addresses and/or site-local addresses based on local configuration? Connections using site-local addresses would not be affected by connection to the Internet. Since so many wise people object to site-local addressing, the problems must be greater than they appear from behind these cube walls. But I have not seen answers to these questions (or maybe I failed to comprehend). I look forward to having my horizons expanded. Julian Sellers Enterprise Server Communications Engineering Unisys Corporation -------------------------------------------------------------------- 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] --------------------------------------------------------------------
