Re: 64-bit identifiers

[Steve Deering <deering@cisco.com>]

At 1:30 PM -0400 8/9/01, RJ Atkinson wrote:
>For an 8+8/GSE-like schema, all systems need to have probabilistically
>unique identifiers.  The current privacy spec guarantees that requirement
>won't be met with the low-order bits of the IPv6 unicast address.

The low-order 64 bits of an IPv6 "privacy" address *is* probabilistically
unique, given that it's a pseudo-randomly-generated 64-bit number.
How low does the probability of collision have to be for your purposes?

>This isn't good or bad, just reality.  So folks looking into 
>8+8/GSE-like schemas need to find/create an alternate identity space 
>for things like PCBs.

Or find/create an alternate locator space (e.g., in an encapsulating
IPv6 or other kind of header), and treat the 128-bit end-to-end IPv6
address as the globally-unique identifier.

Steve