[address-policy-wg] Just say *NO* to PI space -- or how to make it lessdestructive

David Conrad wrote:
> How do you believe folks will do traffic engineering?

This is an interesting point which occurred to me as I was writing my 
last email.  Outside as-path prepending, I don't have a good answer.

Where the relevant organisations have multiple connections to the same 
upstream, it can be managed using no-export subnet announcements 
alongside the main supernet announcement.  But where there are multiple 
upstreams involved this will, of course, not work.  AS path prepending 
will continue work to the extent that it does today, which is to say not 
very well.

But the point remains.  The default LIR allocation size is /32, which 
allows for 65K /48's.  That is a large number of distinct networks, and 
will easily satisfy the long-term requirements of small to medium sized 
ISPs, which - I am going to speculate - comprise the bulk of both AS's 
and prefix announcements.

And if the recommended assignment size were to be changed from /48 to 
/56 - again allowing ample block size for many organisations, that would 
optimise address space utilisation further, making a /32 allocation last 
much longer than previously.

Nick