[address-policy-wg] PI concept in general, was IPv6 PI resource question!

On 16/02/2011 16:28, Martin Millnert wrote:
> Routing slots notwithstanding, the hurdles the RIPE community puts up
> for PIv6 is *directly* contra-productive to roll-out of IPv6 in
> general, and the "end-to-end"-roll-out specifically.

possibly.  But these hurdles are insignificant compared to the other 
hurdles you're going to run into for an ipv6 deployment, including:

- poor vendor support, still
- training and support costs
- poor existing ipv6 connectivity
- low cost:return ratio

Regarding routing slots, here's some hand-waving / back-of-a-napkin / 
finger in the air analysis:

ipv6 generally takes up either 2 or 4 times the amount of lookup engine 
space that ipv4 does (implementation / hardware dependent).  Unique ASNs on 
the internet are currently at about ~37000, and increasing at a rate of 
~2500 a year.  So if we assume that every ASN gets at least one IPv6 prefix 
in the next two years, and there's going to be an average of 1.4 prefixes 
per ASN (which seems to be what it's at right now), in two years time, we 
end up with the following number of TCAM slots (assuming 4 x ipv4 = 1 x ipv6):

(37000 + 2500*2) * 1.4 * 4 = 235000 ipv4 equivalent slots.

For ipv4, we're currently at 340k and growing at 50k/annum.  In two years, 
we might be at 440k slots, assuming that resource exhaustion doesn't cause 
massive de-aggregation.

This would indicate maybe around 675k ipv4-equivalent lookup engine slots. 
  Then you add in your mpls, IGP and multicast slots.

So, within 2 years on a small network, 1m route lookup entries may still 
work, but almost certainly will not work on a large network.

If there is massive ipv6 deaggregation, it will cause 4x the damage of the 
equivalent ipv4 deaggregation.  This is bad, and it will cost lots of 
people lots of money.

Nick

--
[note: while no animals were harmed during the production of these numbers, 
they are basically pulled out of a hat with no real consideration of 
whether they might correlate to reality in any way.  Please don't bother 
trying to argue with me about them.  I _will_ deny everything / plead 
insanity / blame it on the cat taking over my keyboard]