Re: google ipv6 routes via cogent

[Job Snijders <job () instituut net>]

On Fri, Mar 03, 2017 at 09:42:04AM -0500, Patrick W. Gilmore wrote:
> On Mar 3, 2017, at 7:00 AM, Nick Hilliard <nick () foobar org> wrote:
> > Niels Bakker wrote:
> > > As I explained in the rest of my email that you conveniently didn't
> > > quote, it's so that you can selectively import routes from all your
> > > providers in situations where your router cannot handle a full table.
> >
> > it can also break horribly in situations where the provider is providing
> > "transit" but doesn't provide full transit.
> >
> > OTOH, if you are single-homed, it is highly advisable to accept a
> > default, the reason being that most transit providers provide bgp
> > communities with "don't advertise to customers" semantics.  So if you're
> > single-homed and use a full dfz feed without default route, you will not
> > have full connectivity to all the routes available from the transit
> > provider.

Correct.

> If you are single-homed, there is no need for BGP at all.

That is very strongly worded, and in plenty of cases a false assertion.

> And injecting your ASN into the table is probably not terribly useful
> to everyone else’s FIB.

ASNs don't have anything to do with FIB.

> There are, of course, corner cases. But in general, single-homed
> people shouldn’t be using BGP.

There are numerous reasons to use BGP when single-homed:

    - as preparation to multi-home in the (near) future
    - ability to quickly change providers
    - to use BGP based blackholing features
    - to save time on provisioning work (adding new prefixes becomes a
      matter of just announcing and updating IRR/RPKI).
    - loadbalanacing / loadsharing across multiple links
    - ability to use bgp communities for traffic engineering

In other words, if you have your own IP space, I'd recommend to get your
own ASN and use BGP.

Kind regards,

Job