[arin-ppml] Routing Scaling Problems

John Curran jcurran at istaff.org
Tue Sep 2 01:47:07 EDT 2008

On Sep 1, 2008, at 9:42 PM, Robin Whittle wrote:
> Short version:   I think that the routing scaling problems will not
>                 be so severe as to lead to widespread IPv6-only
>                 adoption in the foreseeable future.
>                 The only routers which will be affected
>                 significantly by the growing number of DFZ routes
>                 will be those of transit providers and large ISPs
>                 where the routers have the highest number of
>                 neighbours.  I believe the operators of those
>                 routers will always find it better to upgrade or
>                 replace those routers, or to limit the number of
>                 neighbours they connect to, rather than drop some
>                 DFZ routes and therefore provide a second-rate
>                 service.

"Second-rate" service is a matter of perspective, since the
alternative of continuously upgrading all of the DFZ routers
in a major transit-free ISP (presuming the equipment of that
scale is even available) means enormous capital expenditures,
and to do so solely because other providers are filling up
routing tables with fragments would require some interesting
financial justifications in any company.

Given that some providers are already having trouble keeping
up, is it your assumption that all "tier one" providers simply
have no choice, and pass along these ever increasing costs to
their existing customers?  It would only take one backbone ISP
to opt instead to drop "less popular" routes and have much lower
costs to make for some very interesting competitive pressure.


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