RE: Internet routing table "completeness" monitoring?

["William F. Maton Sotomayor" <wmaton () ottix net>]

On Wed, 3 Oct 2012, Joseph Jackson wrote:

> I have cacti graph the amount of prefixes announced and withdrawn from a BGP peer on each BGP router.

+1

Note that not all router OSs support fetching data like that via SNMP.

We use a custom built thing internally that does this two, which we then 
tack on an alert threshold for.  So if a downstream peer sends us less 
than that, we get an alert.  Handy for those times when they call and ask 
us what we did to their network. :-)

Prior to that, we had a script which whould login, munge the 'show ip bgp 
summary' table output, figure out the deltas and graph or report as 
needed on a particularly troublesome peer.

> -----Original Message-----
> From: ML [mailto:ml () kenweb org]
> Sent: Tuesday, October 02, 2012 11:43 PM
> To: North American Networking and Offtopic Gripes List
> Subject: Internet routing table "completeness" monitoring?
>
> Has anyone put in place a method to identify if one their BGP peers suddenly withdraws X% of their prefixes?
>
> e.g I should expect ~420k prefixes in a "complete"[1] routing table from a transit peer today.  If suddenly I'm only getting 
> 390k prefixes I'd guess a major network was depeered or similiar.
>
> If so how are people doing this? SNMP MIB, screen scrape?
>
>
>
> [1] Varying levels of completeless apply.

wfms