[c-nsp] NPE-G1 high CPU utilization due to 'BGP Router'

[Hauke Krull]

Hi,

just for the record:

Ben Steele schrieb:
> None of your neighbors are flapping or at least their route tables?  

No.

> could be BGP RIB tables constantly being updated by unstable peer,  
> check to see if any have excessive updates, is the router meshed with  
> any others via iBGP? 

Yes an iBGP-mesh.

The cause seems to be that this router constantly (every 0.1 second) withdraws
1 prefix (lets say x.x.x.x/19 - wich doesn't originate from our AS or our 
customers but is learned via eBGP) - it generates updates to all iBGP and 
eBGP-Peers (these are filtered of course):

Feb 25 10:29:31.098 MET: BGP(0): Revise route installing 1 of 1 routes
for x.x.x.x/19 -> a.a.a.49(main) to main IP table
Feb 25 10:29:31.098 MET: BGP(0): updgrp 1 - z.z.z.z updates
replicated for neighbors: ...
Feb 25 10:29:31.098 MET: BGP(0): z.z.z.z send unreachable x.x.x.x/19
Feb 25 10:29:31.098 MET: BGP(0): z.z.z.z send UPDATE x.x.x.x/19
-- unreachable
Feb 25 10:29:31.098 MET: BGP(0): updgrp 2 - a.a.a.49 updates
replicated for neighbors: ...
Feb 25 10:29:31.198 MET: BGP(0): Revise route installing 1 of 1 routes
for x.x.x.x/19 -> a.a.a.49(main) to main IP table


show ip bgp x.x.x.x/19 shows:
BGP routing table entry for x.x.x.x/19, version 267318576
Paths: (2 available, best #2, table Default-IP-Routing-Table - next-hop
mismatch)
Flag: 0x820
  Not advertised to any peer
  A B C, (aggregated by C z.z.z.z)
    w.w.68.89 from w.w.68.89 (w.w.69.124)
      Origin IGP, localpref 100, valid, external, atomic-aggregate
  D C, (aggregated by C z.z.z.z)
    a.a.a.49 (metric 161280) from a.a.a.49 (a.a.a.51)
      Origin IGP, metric 0, localpref 100, valid, internal, atomic-aggregate,
best


A collegue of mine is further investigating this under a new subject on this
list ('BGP question') to discover the cause for this 'next-hop mismatch'.

Thanks
 Hauke Krull
-- 
Dipl.-Phys. Hauke Krull

NetUSE AG
Dr.-Hell-Straße 6
D-24107 Kiel
Tel: +49 431 2390 400
Fax: +49 431 2390 499
http://www.NetUSE.DE/

Vorstand: Andreas Seeger (Vorsitz), Dr. Roland Kaltefleiter, Dr. Joerg Posewang
Aufsichtsrat: Detlev Huebner (Vorsitz)
Sitz der AG: Kiel, HRB 5358 USt.ID: DE156073942

Diese E-Mail enthaelt vertrauliche oder rechtlich geschuetzte Informationen.
Das unbefugte Kopieren dieser E-Mail oder die unbefugte Weitergabe der
enthaltenen Informationen ist nicht gestattet.

The information contained in this message is confidential or protected by
law. Any unauthorised copying of this message or unauthorised distribution
of the information contained herein is prohibited.