Measuring BGP routes

Sun Aug 25 19:43:34 UTC 2002

Bradley et al,

FYI, the "advertise-inactive" feature was (at least until very recently)
a documentation bug.  See the message included below from John Allen at
Junper.

Cheers,
Nick

------------------

Jennifer,

I just filed a doc-bug for this.  Our documentation reads, "By default,
BGP stores the route information it receives from update messages in the
JUNOS routing table, and the routing table exports only active routes
into BGP, which BGP then advertises to its peers. To have the routing
table export to BGP all routes learned by BGP even if the JUNOS software
did not select them to be active routes, include the advertise-inactive
statement."  However, this is not correct.

Sorry for the spam ;)

-John

-----Original Message-----
From: Jennifer Rexford 
Sent: Wednesday, June 26, 2002 4:28 PM
To: John Allen
Subject: Re: Question on slide from "Controlling the Impact of BGP
Policy Changes on IP Traffic"

John,

> One of our customers was at Nanog and caught your presentation.
> They are interested in the slide on page 11 and the bullet point
> "Juniper support for outputting a feed of all BGP routes."
> I'm not clear from the context what feature you might have been
> referring to.  Would you mind clarifying?

We were referring to the "advertise-inactive" feature described at

http://www.juniper.net/techpubs/software/junos42/swconfig-routing42/html
/bgp-config38.html#1015169

This is nice for getting a live feed of all of the routes advertised by
the eBGP neighbors of an operational router.

-- Jen

On Fri, Aug 23, 2002 at 12:40:56PM -0700, Bradley Dunn wrote:
> 
> On 23 Aug 2002, Jeff S Wheeler wrote:
> 
> > On Fri, 2002-08-23 at 15:05, Frank Scalzo wrote:
> > *edited for length*
> > > Most of the tools I have seen have basically done a show ip bgp
> > > collected the whole table and parsed it. I know I wrote a tool like that
> > 
> > Is there any reason this is preferable to establishing an eBGP multihop
> > session with the box and receiving the information by that means?
> 
> Yes.
> 
> BGP only passes along the best route. 'show ip bgp' gives you all routes. 
> Unless, of course, your vendor supports something like Juniper's 
> "advertise-inactive".
> 
> Bradley