At 04:22 AM 5/27/2003, Brian E Carpenter wrote:
Now, as a pragmatist, I would probably settle for a pseudo-random and probably-unique /48, but not everybody will. I can just imagine a phone call in which I recommend to IBM's chief network architect to use address space that *probably* nobody else is using.
Do other people think we need a guaranteed-unique mechanism for limited-scope addresses, or is probably-unique enough?
My take on the discussion is that we need both. There are organizations who prefer to go to a registry to get some guarantee of uniqueness and others who prefer to generate a prefix themselves.
Your earlier suggestion of
I wouldn't have a problem with a variant of Bob's proposal in which (for example) FC00::/8 is followed by a 40 bit ID allocated as Bob suggests, and FD00::/8 is followed by a user-assigned 40 bit ID. Then FC00::/7 would be the prefix for all limited-scope addresses.
appears to be a reasonable approach where the 40 bit ID under FD00:/8 would be selected by running an algorithm that would have to be specified.
There is a clear tradeoff between a longer ID (to allow for better random numbers or MAC addresses) and the size of the subnet field.
Before revising the draft, I would prefer to hear from more people on these tradeoffs.
Bob
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