GSE IDs [Re: IETF multihoming powder: just add IPv6 and stir]

[Brian E Carpenter <brian@hursley.ibm.com>]

Peter Tattam wrote:
...
> >
> > 3) We know from previous discussion that 64 bits is too short for a
> > randomly assigned global space;
> 
> I thought we were talking about a M + S + 64 bits address space where the M
> bits can be guaranteed globally unique and the S bits are managed by the site.
> For the purposes of global routing, this is unique enough to guarantee no
> collisions.  The uniqueness of the 64 bits within the local segment are managed
> by existing mechanisms of address autoconfig.

That isn't the only requirement. If the M is mutable and the S has no 
particular reason to be unique, then if you have a set of peers 
intercommunicating, you've only got the 64 bit IDs available to act as 
unique IDs for transport end-point and security end-point identification.

So there is a strong requirement that the 64 bit IDs be unique within
any set of intercommunicating peers. (In the case of TCP, the set has
two members; in the case of FTP it's any number, by use of the PORT
command.) 

   Brian