Verio Decides what parts of the internet to drop

Randy Bush rbush at
Thu Dec 2 23:46:47 UTC 1999

> Your pager didn't go off when the routing table had 100k prefixes in
> it, I take it.

i read about the incident on this mailing list.  and, more importantly,
our customers did not feel it except as inability to get to the networks
which implemented routing policy via pager.

alex rubenstein:
>> I believe that if I have a customer who is multihomed between me and
>> another provider, his punch-throughs to the non-address-space-providing
>> provider should be heard. It's called 'global routability.'

it is not ours to say what should be heard, i.e. what our peers accept.
it is ours to say what we announce.  and indeed for verio customers we
are willing to announce long prefixes from other providers' spaces.
heck, for multi-homed customers, we are willing to announce longer
prefixes which punch holes in our own larger space, allowing them to
more easily play load balancing games.

>>> the routing databases are not great, and many routers can not handle
>>> ACLs big enough to allow a large isp to irr-filter large peers.  and
>>> some large peers do not register routes.
alex rubenstein:
>> There are ways to get around this (as-path filtering, maximum-paths,
>> etc) that aren't as nazi as one would hope, but will prevent
>> stupidity and provide sanity checking.

many things which might work for a small 42nd tier isp do not scale to a
tier one provider.  and i share jared's scepticism that these hacks work
for even the teenies, i.e. the 129/8 disaster was from a direct peer.

>>> verio's policy has been constant and public.
alex rubenstein:
>> But unfortunate. Will they announce a customer-announced /24?
> Yes.  They can't guarentee that peers will listen to it though.

bingo.  and not to announce a customer route would preempt our peers'
ingress route filtering policy choices.


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