[ppml] Policy Proposal 2002-3

Trevor Paquette Trevor.Paquette at TeraGo.ca
Tue Oct 7 11:56:06 EDT 2003

Finally a decent answer to expain historically why boundaries were moved.

> -----Original Message-----
> From: Lea Roberts [mailto:lea.roberts at stanford.edu]
> Sent: Tuesday, October 07, 2003 12:31 AM
> To: Trevor Paquette
> Cc: ppml at arin.net
> Subject: RE: [ppml] Policy Proposal 2002-3
> Trevor -
> the basic problem is that old model for everyone to get 
> direct assignments
> from the InterNIC (or now the RIRs :-) just doesn't scale.
> in the early 1990s, it was asserted that IPv4 addresses were being
> consumed too rapidly.  Back then addresses were assigned in "classes". If
> a site needed more than a /24 (Class C) they would get a /16 (Class B) and
> class B assignments were being made at an increasingly rapid rate.  In
> response to this, Classless InterDomain Routing (CIDR) was born and
> addresses could be assigned more efficiently with variable "prefix"
> lengths. (see RFC 1519, September 1993)
> then, as Owen has said, there were problems with the explosion of routing
> table size approaching the limits of the hardware then running in the
> core.  the solution was to encourage hierarchical address assignment, also
> known as provider assigned addresses, so that an ISP could aggregate a
> number of its sites into one advertisement into the global routing table.
> thus CIDR came to the rescure for the routing table problem as well.
> it's taken most of these ten years for the paradigm shift to solidify and
> I would hate to see a rush back to where individual assignments from an
> RIR would be the norm rather than a special case.
> note there is another dichotomy.  when ARIN makes address assignments, it
> cannot guarantee the routability of the addresses.  there are other
> players in the scene, e.g. the network operators.  they can negate the
> effect of a prefix length change by refusing to accept the routes.  an
> unroutable assignment is not worth much!  :-)
> since ARIN was formed, one of the challenges has been to establish
> policies that preserve the stability of the internet while allowing it to
> continue to expand.  the struggle over micro-assignments is ongoing, many
> of us who were around 10 years ago still feel that it is wise to be
> cautious in changing the size of assignments.  there are ongoing studies
> on the next potential for network instability: the convergence time after
> route flaps, which is also related to the routing table size.
> so while router hardware has improved, there may need to be protocol and
> other software improvements in the backbone before advocating the end of
> hierachical address assignments makes sense.  As the "swamp" of original
> address assignments reminds us and as you express as a wise concern, the
> assignment of addresses is almost completely a one way street.  once the
> boundary is moved, we won't be able to undo the assigments should the next
> performance barrier be reached.  thus some of us on the Advisory Council
> are suggesting that these changes should be gradual and their effects
> monitored carefully before moving the boundary again.
> 		there's never a dull moment in networking land,  /Lea
> On Mon, 6 Oct 2003, Trevor Paquette wrote:
> >
> > Folks used to be able to receive direct assignments from 
> ARIN (and other registries) in the past. This ability was 
> revoked for some reason, and it seems that no-one can remember why...
> >
> > I'd hate for us to go back down the same path and encounter 
> the same problems as did our predecessors only to later go 
> 'DOH!.. no wonder they revoked this ability'.
> >
> > Why was this ability revoked and the current policy put in 
> place?? Can anyone explain that?

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