[ppml] Technical reason why /52,/56,/60,/64 are bad

[Robin Whittle]

Michael Dillon quoted something I wrote on the IETF list, in
response to the PPML message:

   http://lists.arin.net/pipermail/ppml/2007-August/008521.html

It was my initial impression that these longer prefixes, to /64,
were being assigned (allocated? - I get confused with the
terminology) by RIRs as PA space for end-users.  That would mean
that there would be BGP advertised prefixes of this length, with the
consequent need for all BGP routers to process 64 bits of
destination address of some packets in their FIBs.

After I wrote my first message, which Michael quoted, I read the
PPML message more carefully and saw that it concerned LIRs
(effectively ISPs, I think) providing PI space for their customers.
 This would mean that the /64 prefixes would not be advertised in
BGP.  So I wrote a retraction to the IETF list:

  http://www1.ietf.org/mail-archive/web/ietf/current/msg47249.html

Can someone confirm my second understanding is correct?

 - Robin