bgp question

Hi all

Thank you all for your answer to my previous question
'RFC1918 from ISP'

I have another BGP question, and may be related to BGP
dampening.

We have a client whose IP is in the block X.X.0.0/19
which doesn't
show in our router.  However, our BGP log records that
we have
received this route from our peer isp.  I reboot the
router, seeing that the route was
in our router only to disappear again after couple of
minutes.  I
suspect that it may have been removed by the BGP
dampening feature in
our router.  By disabling the feature, the route will
stay in our
router.

Q1/ My only understanding of the benefit of this
feature is to prevent
'unstable' route from flooding to our router, causing
a CPU overflow.
What's the risk of leaving this off?

Q2/ What is the cause of these route that frequently
send to our
router as stated below?  Once our other routes are in
our BGP DB, then
it will not be re-broadcast to us except withdraw from
our peer isp

> 2006/05/26 08:30:34 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:33:42 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:36:46 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:39:49 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:45:25 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:48:00 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:49:02 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:51:34 BGP: our-peer-isp rcvd
x.x.0.0/19
> 2006/05/26 08:52:36 BGP: our-peer-isp rcvd
x.x.0.0/19

Q3/ Do you know any good website to montior the
routing network?
I just heard this scoreboard.keynote.com from
http://isc.sans.org/dia
ry.php
but it needs register

Thank you very much

> I suspect that it may have been removed by the BGP
dampening feature
> in our router. By disabling the feature, the route will
stay in our 
> router.

> Q1/ My only understanding of the benefit of this
feature is to
> prevent 'unstable' route from flooding to our router,
causing a CPU
> overflow. What's the risk of leaving this off?

things have changed. BGP route dampening is considered
harmful. just
turn it off.

http://ww
w.ripe.net/ripe/docs/ripe-378.html

[..]
4.0 Recommendation

This Routing Working Group document proposes that with the
current
implementations of BGP flap damping, the application of flap
damping in
ISP networks is NOT recommended. The recommendations given
in ripe-229
and previous documents [2] are considered obsolete
henceforth.

If flap damping is implemented, the ISP operating that
network will
cause side-effects to their customers and the Internet users
of their
customers' content and services as described in the
previous sections.
These side-effects would quite likely be worse than the
impact caused by
simply not running flap damping at all.
[..]