[j-nsp] [c-nsp] how many IGP routes is too many?

[Saku Ytti]

On Wed, 8 Apr 2020 at 00:55, Nick Schmalenberger via juniper-nsp
<juniper-nsp at puck.nether.net> wrote:

> Yes, according to this very interesting experiment
> http://www.blackhole-networks.com/OSPF_overload/ it is mostly
> about memory and cpu load :)

Interesting, but this is the worst case scenario for ISIS, single
router advertising many routes. In ISIS this would have had less happy
ending, as you only have 255 LSP numbers, ~1500B each, so after ~370kB
or so, you'll run out of space where to put your routes.
There are some protection mechanism for this scenario, IOS has
'lsp-full suppress interlevel external' and JunOS has
'prefix-export-limit'

Very different to advertise say 1M routes from 1router (won't work)
than advertising 1k routes from 1k routers each (no particular reason
why it wouldn't work).