Re: IPv4 v IPv6
Hello,
On Mon, Jun 17, 2019 at 04:11:32PM -0400, Robin Hammond wrote:
> The size of such a routing table gives me nightmares ! Thank goodness you
> have to advertise networks of a reasonably sized prefix length!
I wouldn't worry too much about the number of v6 routes. In terms of
addressing and routing policy, this second go with v6 has afforded
some chances to correct mistaken assumptions made with v4 that later
became impossible to undo.
I would worry more about the number of v4 routes. As v4 runs out
globally (already has in some regions), there is increased pressure
to carve up allocations so that they can be traded. For example, if
you look at an arbitrary v4 auction site:
https://auctions.ipv4.global/
(I picked this from a web search and have no information about it,
so it's not an endorsement)
You see that an ARIN /24 (256 addresses) currently goes for around
$5.6k. Let's say you have a /21 but you're only using the bottom
half. At the moment your route in the global routing table is a
single /21 route. But hey, people want to buy IPs, and you have 8
/24s in your /21. You're only using 4 of them (the bottom half as I
say). So you auction the top 4 off to 4 different buyers. Now the
global routing table needs one /22, for your bottom half, and then
four /24s, so it grew by 500%.
It is not yet quite that bad because a /24 is really still a bit too
small to route. Some providers may not accept the announcement. But
as the availability goes down and the prices go up, people are going
to want to route /24s routinely.
That is on top of the number of orgs who got an allocation that
proved to be too small so they went back for an extra one, thus
doubling the number of routes.
Meanwhile in IPv6 land, Regional Internet Registries tried really
hard to give out allocations so big that very few applicants should
ever need to come back for a second one (and thereby introduce
another global route).
Cheers,
Andy
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