I absolutely could do as you suggest, and simply generate multiple /48s. If we use that logic though - if you need more than a /48 just use multiple /48s, then rather than have some organizations get larger space from an ISP (like /46), we should just give them multiple /48s too - different parts of the world, big internal private network - and let them use internal routing to bring the enterprise together.
So, in 99% of cases, I suppose, the multiple /48s would work. It just might not be quite as clean. If you said to a site "you can either generate yourself FD85:19EA:73C8::/47, or you can generate and use FD85:19EA:73C8::/48 and FD1B:9567:CD12::/48", enterprises would choose a contiguous /47 in most every case. If the draft essentially let people append as many bits as needed to "FD" to generate the length prefix they desired, for internal use, the process would be a bit more flexible. These are internal-use-only addresses, and the draft could advise people that the larger the prefix they generate the larger the chance they might, should they merge networks with some other organization, encounter an address space collision. Engineers at that site could weigh the options and make a choice. I understand we would not want to allow larger-than-some-threshold (maybe /48) "FC" (centrally registered) addresses, as that is a shared pool that vitally depends on their being very, very few collision, and we would not want an organization to "claim", say "FC45::/16". So, just a thought. I believe this draft is about to go RFC, and I don't want to trip up the process, because it is a very good draft and I'm anxious to see vendors implement it. Just a question, really. John Spence > -----Original Message----- > From: Pekka Savola [mailto:[EMAIL PROTECTED] > Sent: Friday, September 23, 2005 1:46 AM > To: John Spence > Cc: [email protected] > Subject: Re: Can I generate a prefix shorter than /48 using > <draft-ietf-ipv6-unique-local-addr-09.txt>? > > On Thu, 22 Sep 2005, John Spence wrote: > > If my organization is large, and I will petition my ISP for > a /44, or > > even a /40, I'd like to be able to use the mechanism > outlined above to > > randomly generate myself a Unique Local /40 prefix so I can map my > > routable and site-restricted space as I desire. > > > > I did not see a provision in the draft that would allow me > to do that. > > Is that correct - there is no provision for generating a shorter > > prefix? > > Why would you even need to? If you have so many subnets, > they are probably NOT located in one physical location. You > could just generate multiple ULA prefixes (e.g., one per > physical site, one per continent or whatever) and hook them > together in the routing? > > -- > Pekka Savola "You each name yourselves king, yet the > Netcore Oy kingdom bleeds." > Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
