[c-nsp] IOS XR BGP

[Keegan Holley]

2011/11/29 Gert Doering <gert at greenie.muc.de>

> Hi,
>
> On Tue, Nov 29, 2011 at 08:04:42AM -0500, Keegan Holley wrote:
> > >> That's crap.
> > >
> > > In that case: "I encourage all my competitors to do so".
> > >
> > > What's your AS number?  Shall we see what happens if I announce the /24
> > > with your name servers in it?  (Except that I'm a good guy, and would
> > > never do that, of course).
> >
> > Yea sure. I have a better test.  Why don't you tell one of your upstreams
> > that you want to advertise a block they've given you to another ISP for
> > redundancy.  Just because you accept a few routes with LOA agreements
> > doesn't mean you accept any route from any as path.
>
> Thanks for making this very clear: it is *very* important to *not* accept
> just about anything that comes along - and filtering "routes from my
> network blocks" plus "routes for any exchange points I'm connected to"
> is really "basic network stability 101".
>

I agree with that completely.  I think there were alot of misunderstandings
in our discussion.

>
> Most ISPs these days do not seem to have customers that use BGP-based
> multihoming using networks from the ISP's PA blocks - but of course,
> exceptions happen (we have one customer that uses an IPv6 /48 from our
> /32 due to historic reasons).
>

There's no real way to multi-home and not change address space other than
multihoming.  That's why there are so many wasted /24's and AS numbers out
there.

>
> > What's the alternative?  Yet another AS with a single /24 and 10 web
> > servers living unit because their provider wouldn't multihome?
>
> Where exactly is the difference between "one globally visible route" and
> "one globally visible route"?  And what does this have anything to do
> with prudent route filtering?
>

It's really the wasted ARIN/RIPE assignment in the IP4 exhaustion phase.
You're right though what I said here wasn't 100% accurate.  If you
multihome ISP number 1 would have to give you a /24 or larger.

>
> gert
> --
> USENET is *not* the non-clickable part of WWW!
>                                                           //
> www.muc.de/~gert/ <http://www.muc.de/%7Egert/>
> Gert Doering - Munich, Germany
> gert at greenie.muc.de
> fax: +49-89-35655025
> gert at net.informatik.tu-muenchen.de
>