Brian E Carpenter wrote: > > For the record, I am still completely against any proposal > that takes over the normal 16 bit subnet field, i.e. > generates a prefix longer than /48. It just isn't > operationally convenient.
I'm still unsure about this insistence on /48 as a critical point of allocation. /64 as a critical makes sense, as it is configured as the changeover from subnet allocation to host allocation (for unicast addresses at least). But as for /48, consider these examples: My home (say 4 subnets) is given a /48 for my SOHO network. The local university (say 100 subnets) is given a /48 for the campus. Multinational X (say 5000 subnets) is given a /48 for their entire VPN. Only one of the above needs anything like a /48. Next example, let's consider inside multinational X. I want to allocate subnets to sites. /48 is our standard allocation, right? But I can't allocate /48s, because /48 is the allocation for the entire VPN, so I instead allocate something smaller (probably a /56). Now let's assume that said site wants to create a site-local network (not sure why, since they're 'permanently' connected, but let's run with it). Why is the number /48 somehow magical for this site, considering they have a /56 delegation? All they really want is a way of generating internal /64 subnets. /64 marks a well defined physical entity: the subnet, although even that can be redefined if the address allocator wishes it. /48 is a convenient mark for a logical entity: the 'end-user' network. In practice, these vary radically in size and may be further subdivided, so /48 is merely a useful convention. -- 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] --------------------------------------------------------------------
