From: Edwards, Andrew M (andrew.m.edwards@boeing.com)
Date: Tue Sep 28 2004 - 17:39:33 GMT-3
Then, if I were only asked to dampen ONE route, and I match it with the
first sequence of the route-map, I wouldn't need an additional sequence
because I have no other routes I want to dampen... True?
-----Original Message-----
From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]
Sent: Tuesday, September 28, 2004 11:53 AM
To: Matt; ccielab@groupstudy.com
Subject: RE: Ccie R&S lab 3 questions for the list....
Matt,
Dampening is applied on the router itself not on a specific
peering. This is why it doesn't relate to what it advertised. When you
call your route-map you need to call it like this:
router bgp 1
bgp dampening route-map DAMPEN
If you then want to filter what is advertised to a specific peer
create another route-map for that purpose and apply it to the peer.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: Matt [mailto:matt_ccie_2004@yahoo.com]
> Sent: Tuesday, September 28, 2004 1:41 PM
> To: Brian McGahan
> Subject: RE: Ccie R&S lab 3 questions for the list....
>
> Actually, maybe I am missing something here.
>
> R1 is advertising 3 /32 routes to R3:
>
> R3#sh ip bgp
> BGP table version is 4, local router ID is 1.1.1.2
> Status codes: s suppressed, d damped, h history, *
> valid, > best, i - internal,
> r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf
> Weight Path
> *> 1.1.1.1/32 10.1.1.1 0
> 0 1 i
> *> 2.2.2.2/32 10.1.1.1 0
> 0 1 i
> *> 3.3.3.3/32 10.1.1.1 0
> 0 1 i
> R3#
>
> now when i add the following route-map to that
> peering:
> route-map dampen permit 10
> match ip address prefix-list Dampen
> set dampening 2 15 15 2
>
> ip prefix-list Dampen seq 5 permit 1.1.1.1/32
>
> R3(config)#router bgp 2
> R3(config-router)#neigh 10.1.1.1 route-map dampen in
> % "dampen" used as BGP inbound route-map, set
> dampening not supported
> R3(config-router)#^Z
> R3#
> 01:44:11: %SYS-5-CONFIG_I: Configured from console by
> console
> R3#
> R3#clear ip bgp * s
> R3#sh ip bgp
> BGP table version is 6, local router ID is 1.1.1.2
> Status codes: s suppressed, d damped, h history, *
> valid, > best, i - internal,
> r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf
> Weight Path
> *> 1.1.1.1/32 10.1.1.1 0
> 0 1 i
> R3#
>
> it gives me an error, yet it only allows the route
> specified by the prefix list since I do not have a
> permit 20 statement.
>
> thoughts? (didn't want to spam the whole list with
> this)
>
>
>
>
>
>
>
> --- Brian McGahan <bmcgahan@internetworkexpert.com>
> wrote:
>
> > Actually this second route-map statement will not accomplish
> > anything, because the routes will not be dampened
> > unless specific
> > dampening parameters are applied to them. This is
> > not to say that the
> > routes will or will not be used or advertised,
> > simply that they will not
> > be dampened regardless whether the second route-map
> > sequence is there or
> > not.
> >
> >
> > HTH,
> >
> > Brian McGahan, CCIE #8593
> > bmcgahan@internetworkexpert.com
> >
> > Internetwork Expert, Inc.
> > http://www.InternetworkExpert.com
> > Toll Free: 877-224-8987 x 705
> > Outside US: 775-826-4344 x 705
> > 24/7 Support: http://forum.internetworkexpert.com
> > Live Chat: http://www.internetworkexpert.com/chat/
> >
> >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com
> > [mailto:nobody@groupstudy.com] On Behalf
> > Of
> > > Matt
> > > Sent: Tuesday, September 28, 2004 11:02 AM
> > > To: Edwards, Andrew M; ccielab@groupstudy.com
> > > Subject: Re: Ccie R&S lab 3 questions for the
> > list....
> > >
> > > regarding the second permit statement in the
> > dampening
> > > route-map...that statement is there to permit
> > anything
> > > else not specified in the first statement.
> > Without
> > > it, the rest will be denied.
> > >
> > > -matt
> > >
> > > --- "Edwards, Andrew M"
> > <andrew.m.edwards@boeing.com>
> > > wrote:
> > >
> > > > For those of you familiar with the lab, I'd
> > > > appreciate any feedback.
> > > > Especially on bgp dampening because I think I
> > really
> > > > need to get the
> > > > purpose of the second route-map permit sequence.
> > > > Re: requirement to not accept routes from any
> > other
> > > > EIGRP routers on
> > > > VLAN 1 that may be added in the future
> > > > The author used a distribute list with the
> > gateway
> > > > statement to allow
> > > > only R2 to provide updates to R3 on this VLAN.
> > > > I used a different method and wanted to run it
> > by
> > > > the groupstudy.
> > > > I used the distance command such that there were
> > two
> > > > entries in the
> > > > following order:
> > > > 1. distance 90 172.16.0.1 0.0.0.0
> > > > 2. distance 255 172.16.0.0 0.0.255.255
> > > >
> > > > With this configuration, R3 became adjacent to
> > > > another router (I used
> > > > the 3550 switch to test) on the VLAN, but DID
> > NOT
> > > > take any routing
> > > > updates from it.
> > > > Would this have also met the requiremet from the
> > > > lab? Curious...
> > > > re: bgp dampening
> > > > I noticed that there were 2 route map sequences
> > in
> > > > the solution.
> > > >
> > > > I am not sure what the purpose is to the final
> > > > route-map sequence
> > > > "permit 20". Can someone elaborate?
> > > >
> > > > Generally it was this in Lab 3:
> > > >
> > > > bgp dampen route-map dampen
> > > >
> > > > route-map dampen permit 10
> > > > match ip add 3
> > > > set damp x x x x
> > > >
> > > > route-map dampen permit 20
> > > >
> > > > access-list 3 permit ip w.x.y.z 0.0.0.15
> > > >
> > > > re: bgp rib failures
> > > > The author indicates that all the IGP routes
> > should
> > > > be backdoored for
> > > > full points.
> > > >
> > > > If you only backdoor the peered eBGP neighbor
> > > > networks though the routes
> > > > will stop flapping and the other routes will
> > just be
> > > > eBGP instead of
> > > > OSPF.
> > > >
> > > > Is it true, in a lab environment, that we should
> > > > ALWAYS set backdoor
> > > > routes for IGP learned routes over EGP routes?
> > > >
> > > > Andy
> > > >
> > > >
> > >
> >
>
This archive was generated by hypermail 2.1.4 : Fri Oct 01 2004 - 15:00:50 GMT-3