Faster 'Net growth rate raises fears about routers

Tue Apr 3 17:10:52 UTC 2001

First off, let me just say that I'm not speaking for my employer on
this, okay?  Thanks.  

The people who prevent the current global routing table from being
flooded by /25-/30 announcements are also the people who punch holes
in their address space for /24s.  Abha's numbers at the ptomaine BOF
clearly show the effect of RIR policies (spikes around /20 and /19),
but the bigger effect from my perspective was the spike around /24,
created (I presume) by the punches in CIDR blocks that providers make
to allow multi-homing.  I haven't seen good numbers for the
distribution of punches in a long time, but my limited experience
indicates that those punches are being made fairly randomly within the
provider's allocated address space.  This means that the bit
boundaries don't align and you increasingly have mini-swamps inside
providers' /19s and /20s.

Why are providers doing this?  Someone is paying them to do it.  

Why are customers spending money on this?  My belief is that they
want more say in their own fate.  That may express itself as
a desire for redundancy in the case of catastrophic business failures,
better ability to express their own routing policies, or a simple
worry that they won't get the best price if they have only one supplier.
At the core of this, though, is a desire for more control over something
that they see as increasingly important to their own fate.  

I think there are various short term work-arounds to the current
explosion of paths in the routing tables, and I encourage folks to
join the ptomaine mailing list (ptomaine-request at shrubbery.net) if
they want to contribute to the solution.  But don't try to accomplish
it by reducing the ability of the customer to control their own fate.
There are real economic pressures out there which will prevent that
class of solution from success.  

			regards,
				Ted Hardie

> 
> 
> On Tue, 3 Apr 2001, Yakov Rekhter wrote:
> 
> > > It's possible to 'solve' these problems in the future:
> > > Forbid IP level multihoming for IPv6 which crosses aggregation boundaries.
> > > I.e. absolutly no multihoming that inflates more then your providers
> > > routing tabling, connect to whoever you want, but no AS should emit a
> > > route for any other AS without aggregating it into their own space without
> > > a special agreement of limited scope (i.e. not globally!)
> > 
> > Who is going to "forbid" this ? And who is going to enforce this ?
> 
> Ahem.
> 
> The same people who prevent the current global routing table from being
> flooded by /25 - /30s.
> 
> > > We need to stop looking at IP addresses as host-identifyers (thats what
> > > DNS is for) and look at them as path-identifyers.
> > 
> > Perhaphs. But (stating the facts) for now, both in IPv4 *and* in
> > IPv6 IP addresses carry dual semantics - host-identifiers (aka
> > end-point identifiers) *and* path-identifiers (aka locators).
> 
> I though it was explicit with IPv6 that end-nodes are not-host
> identifyers.
> 
> In the real world today, IPv6 addresses are certantly not
> host-identifyers: Many hosts (including the one I'm typing on) have
> multiple IP addresses, and sites have a farm of web serverers behind a
> single IP address. We may pretend that a IP address means a host, but it
> doesn't.
>  
> 
> 