nanog mailing list archives

Re: Faster 'Net growth rate raises fears about routers


From: Greg Maxwell <gmaxwell () martin fl us>
Date: Tue, 3 Apr 2001 13:51:03 -0400 (EDT)


On Tue, 3 Apr 2001 hardie () equinix com wrote:

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.  


I don't argue that multihoming is bad. I argue that we're doing it in the
wrong place with negitive consequences.


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 agree. However, you can offer even greater control and all the other
benefits of multihoming without doing it at the IP layer.

Multihoming at the IP later thus breaking aggregation is like dumping
toxic waste, it cost is largely carried by those not in recept of it's
benefits or any form of payment.

If we can avoid it while still providing the necessary level of service,
then we should seriously investigate such opportunities.
 
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 () shrubbery net) if
they want to contribute to the solution.

Short term is nice, but it doesn't matter in the long run. :)

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.

I never suggested that, I suggested investigating alternatives which
increase customer choice, performance, reliability, and Internet
scalability and potential measures to make the minor inital cost of
implimentation more acceptable.

The obvious intrest here is that most network operators would not have
their customers multihoming at the IP level and thus preventing 
aggregation and polluting the global routing table is there was another
way to achieve the same benefits.
 



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