From: Sergio Jimenez Arguedas (sejimenez@its.co.cr)
Date: Mon Jun 07 2004 - 15:21:25 GMT-3
Hi Georg,
Thanks for the information!!!
Rgds,
Sergio
----- Original Message -----
From: "Georg Pauwen" <pauwen@hotmail.com>
To: <sejimenez@its.co.cr>; <ccielab@groupstudy.com>
Sent: Monday, June 07, 2004 2:25 AM
Subject: RE: BGP ROUTE-DAMPENING!!!
> Hello Sergio,
>
> there is a bug in certain IOS versions whereby dampened bgp routes may be
> incorrectly unsuppressed. Which IOS are you running ?
> This bug appears in lab siutations, here are the release notes:
>
> If a router is running BGP (Border Gateway Protocol) and configured for
BGP
> dampening, dampened routes may be unsuppressed too early.
>
> The dampening function is operational and with default settings there is
> little
> operational impact. However timed repetion of flapping in a lab scenario
> shows we might unsuppress routes before reaching the lowest threshold for
> the penalty. Namely if a path is suppressed and value of penalty is higher
> than reuse value but lower that suppress penalty, and the path flaps
again,
> it may lead to this situation.
>
> There is no known workaround.
>
> Check this link (if you have a CCO login):
>
>
>
http://www.cisco.com/cgi-bin/Support/Bugtool/onebug.pl?bugid=CSCea45963&cco_product=IOS&fset=&swver=&keyw=bgp%20dampening&target=&train=
>
> Regards,
>
> GP
>
> >From: "Sergio Jimenez Arguedas" <sejimenez@its.co.cr>
> >Reply-To: "Sergio Jimenez Arguedas" <sejimenez@its.co.cr>
> >To: <ccielab@groupstudy.com>
> >Subject: BGP ROUTE-DAMPENING!!!
> >Date: Sun, 6 Jun 2004 15:56:29 -0600
> >
> >Hi Group,
> >
> >I am doing a LAB with Route-dampening in BGP, the problem is the
following:
> >
> >
> >R1 receives the toute 192.168.88.0 255.255.255.0 but It is dampening, so
I
> >applied a route-map DAMPENING in R1.
> >
> >
> >________________________________________________
> >
> >R1#sh ip bgp 192.168.88.0 255.255.255.0
> >BGP routing table entry for 192.168.88.0/24, version 59
> >Paths: (1 available, no best path)
> >Flag: 0x208
> > Not advertised to any peer
> > 64600 (history entry)
> > 172.16.20.5 (metric 65) from 172.16.20.5 (172.16.20.5)
> > Origin IGP, metric 0, localpref 100, external
> > Dampinfo: penalty 2804, flapped 3 times in 00:03:09
> >
> >________________________________________________
> >
> >
> >R1#sh route-map
> >route-map DAMPENING, permit, sequence 10
> > Match clauses:
> > ip address (access-lists): 10
> > Set clauses:
> > dampening 15 750 1500 60
> > Policy routing matches: 0 packets, 0 bytes
> >route-map DAMPENING, permit, sequence 20
> > Match clauses:
> > Set clauses:
> > Policy routing matches: 0 packets, 0 bytes
> >
> >________________________________________________________________
> >R1#sh ip bgp flap-statistics
> >BGP table version is 59, local router ID is 172.16.10.1
> >Status codes: s suppressed, d damped, h history, * valid, > best, i -
> >internal
> >Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network From Flaps Duration Reuse Path
> > h 192.168.88.0 172.16.20.5 3 00:10:07 64600
> >_________________________________________________________________
> >
> >
> >
> >
> >The penalty is 2804 but the route isn4t suppress of the BGP routing
table:
> >
> >It shows the "h" and not the "d", Also the sh ip bgp 192.168.88.0
> >255.255.255.0 doesn4t show the reuse in XXXX time...
> >
> >
> >So I really don4t know What is happening!!!
> >
> >
> >Rgds,
> >
> >
> >Sergio
> >
> >_______________________________________________________________________
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