North American Network Operators Group
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Re: Cost per prefix [was: request for help w/ ATT and terminology]

  • From: Patrick W. Gilmore
  • Date: Sun Jan 20 17:33:15 2008

On Jan 20, 2008, at 3:34 PM, William Herrin wrote:

The difference is much, much, much greater than that.  Can the switch
do ACLs?  Policy routing?  SFlow with the same sampling rate?  Same
number of BGP session?


Is there some alternate piece of cheap hardware that supports the DFZ
prefix count at high data rates but doesn't have those features? If
the answer is no (and I'm pretty sure the answer is no), then the
prefix count remains the proper attribution for the cost delta.

We still disagree.

I notice you cut out the next two sentences:

<quote>
In short, if the table were 50K prefixes instead of 250K, would these pieces of equipment be equivalent? The answer is a blatant "no".
</quote>

If we take out the "proper attribution for the cost delta" out of the equation and the equipment is still not considered equal, I submit your idea of "proper attribution" is, well, not proper.

To be clear, of course there are some people who could use either if the table were 50K prefixes. But the majority of routers in the DFZ cannot be replaced by cheap 1U (or whatever) switches which can do a few 10s of 1000s of prefixes. (Besides, the people who _can_ use them can use them today with properly configured filters, perhaps on the upstream router's side. Which, of course, means the upstream router cannot be one of those cheap switches. :)

Perhaps you should justify numbers with nine zeros a little better before asking me to justify why they are wrong.

--
TTFN,
patrick