Internet routing table "completeness" monitoring?

Jay Ashworth jra at
Wed Oct 3 13:47:18 UTC 2012

----- Original Message -----
> From: "ML" <ml at>

> 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?

Well, if I had to do it, I think I'd just point munin at the router, yes,
using SNMP, and put the prefix count graph up on the Big Wall, as a filled 
curve.  That thing jumps around, someone will likely notice.

This assumes a staffed NOC, of course, but it still gives you something to
look at historically if you note a problem in an unstaffed situation as well.

-- jra
Jay R. Ashworth                  Baylink                       jra at
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274

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