[c-nsp] IOS XR BGP

[Keegan Holley]

On Nov 29, 2011, at 5:44 AM, Gert Doering <gert at greenie.muc.de> wrote:

> Hi,
> 
> On Mon, Nov 28, 2011 at 06:44:48PM -0500, Keegan Holley wrote:
>> 2011/11/28 Gert Doering <gert at greenie.muc.de>
>>> On Mon, Nov 28, 2011 at 11:41:08AM -0500, Keegan Holley wrote:
>>>> That wasn't centered around aggregates and no.  Some of us don't run
>>>> gigantic intercontinental ISP's :) So yes us lowly Tier-II and Tier-III
>>>> AS's may on occasion learn our own routes from an external connection.
>>> 
>>> These lowly ASes urgently need to implement anti-bogon filters on their
>>> eBGP sessions.  NEVER EVER accept prefixes belonging to your address
>>> space from the outside.
>> 
>> 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.  What's the alternative?  Yet another AS with a single /24 and 10 web servers living unit because their provider wouldn't multihome?
> 
>> You will need to do it to have customers multi-home with your
>> ARIN space for one.  Secondly those outside AS's may belong to your company
>> a sister company or an acquisition and you may want to use the eBGP path as
>> a backup. 
> 
> Of course there are valid exceptions.  But they should be *exceptions*.
> 
> ASes relying on "nobody will do that" or (even worse) relying on vague
> and ill-understood BGP preferences will just feel the pain some day.
> 
Nevermind.
> gert
> -- 
> USENET is *not* the non-clickable part of WWW!
>                                                           //www.muc.de/~gert/
> Gert Doering - Munich, Germany                             gert at greenie.muc.de
> fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de