[c-nsp] IOS XR BGP

[Keegan Holley]

2011/11/28 Gert Doering <gert at greenie.muc.de>

> Hi,
>
> 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.  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. That's just what I can come up with off the top of my head.
 There are more nefarious uses such as offloading traffic to a partner or
an IX to avoid having to upgrade core links.   Also, I don't need my
routing vendor to try to think for me, I'd rather have one that's flexible.

Whether eBGP is preferred over iBGP is completely irrelevant on this
> topic, as someone could always fat-finger a more specific of your
> aggregate, and that would always win, no matter what.
>

...

>
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