estimation of number of DFZ IPv4 routes at peak in the future

Owen DeLong owen at
Fri Mar 11 19:53:57 CST 2011

On Mar 11, 2011, at 5:43 PM, William Herrin wrote:

> On Fri, Mar 11, 2011 at 6:39 PM, Justin Krejci <jkrejci at> wrote:
>> On Wed, 2011-03-09 at 09:32 -0500, John Curran wrote:
>>> On Mar 9, 2011, at 12:43 AM, Majdi S. Abbas wrote:
>>>>    I suspect that as we reach exhaustion, more people will be
>>>> forced to break space out of their provider's v4 aggregates, and
>>>> announce them, and an unfiltered DFZ may well approach the 'million'
>>>> entries some vendors now claim to support.
>>> This matches my personal view (and could be viewed as
>>> "success" compared to the 5M estimate of Mr. Herrin...)
>> Are people going to be relying on using default-routing then in the
>> future if they don't upgrade routers to handle large routing table
>> growth? Or perhaps forgo dual-stack and have a separate physical IPv6
>> BGP network from IPv4? Are there any other strategies?
> Hi Justin,
> IMHO, the most sensible strategy is to recognize that that cost of a
> route has been dropping faster than the route count has been rising
> for the past decade. Then recognize that with today's hardware,
> building a route processor capable of keeping up with 10M routes
> instead of 1M routes would cost maybe twice as much... 10M being
> sufficient to handle the worst case estimates for the final size of
> the IPv4 table in parallel with any reasonable estimate of the IPv6
> table in the foreseeable future. Better CPU, more DRAM, bigger TCAM.
> It could be built today.
But the RP is the easy cheap part. It's the line cards and the
TCAM/etc. that they use that gets pricey fast.

> Finally, get mad at your respective router manufacturers for
> engineering obsolescence into their product line by declining to give
> you the option.
The option of $60,000 line cards instead of $30,000 or
even $25,000 instead of $12,000 does not seem like one
that most would have found appealing.

> But that's just my opinion...
And the above is just mine.


More information about the NANOG mailing list