Re: BGP AS-PATH PREPEND

From: marc abel <marcabel_at_gmail.com>
Date: Wed, 8 Jan 2014 11:19:37 -0600

That access-list isn't going to match any routes. Remember you are matching
routes not flows so you can't specify a source and destination.

On Wed, Jan 8, 2014 at 10:53 AM, Cisco Fanatic <ebay_products_at_hotmail.com>wrote:

> Because I only want 10.100.60.11 (source) to go over Layer 2 (a name)
> 10.20.80.11 (destination). The rest should all be prepended.
>
> ip access-list extended OVER_L2
> permit ip host 10.100.60.11 host 10.20.80.11
>
> With your suggestion all the traffic will be prepended (longer AS path)
> and it
> will not be the best route.
>
>
> Date: Wed, 8 Jan 2014 16:36:40 +0000
> Subject: Re: BGP AS-PATH PREPEND
> From: sammybibs_at_gmail.com
> To: ebay_products_at_hotmail.com
> CC: mothafungla_at_gmail.com; ccielab_at_groupstudy.com
>
> I'm pretty sure the route map is wrong here,
>
> !!!Yours
>
> !
> !You match the ACL but don't do anything with it.
> !
>
> route-map AS_CHANGE permit 10
>
> match ip address OVER_L2
>
> !
> ! You then pre-pend everything via the match all in the next statement
> !
>
> route-map AS_CHANGE permit 20
>
> set as-path prepend 65500 65500 65500
>
> !
>
>
> !!!Suggestion
>
> !
> !You match the ACL but don't do anything with it.
> !
>
> route-map AS_CHANGE permit 10
>
> match ip address OVER_L2
> set as-path prepend 65500 65500 65500
> !
>
> \Sam
>
>
> On Wed, Jan 8, 2014 at 4:31 PM, Cisco Fanatic <ebay_products_at_hotmail.com>
> wrote:
>
> Sorry, cut-paste issue, too many notepad open.
>
>
> R1
>
> ++
>
>
> !
>
> router bgp 65500
>
> neighbor 10.255.0.26 route-map AS_CHANGE out
>
> !
>
> route-map AS_CHANGE permit 10
>
> match ip address OVER_L2
>
> !
>
> route-map AS_CHANGE permit 20
>
> set as-path prepend 65500 65500 65500
>
> !
>
> ip access-list extended OVER_L2
>
> permit ip host 10.100.60.11 host 10.20.80.11
>
> !
>
>
> It is still going over the other connection...
>
>
> R1#traceroute 10.20.80.11
>
> Type escape sequence to abort.
>
> Tracing the route to 10.20.80.11
>
> VRF info: (vrf in name/id, vrf out name/id)
>
> 1 10.255.255.1 4 msec 0 msec 4 msec
>
> 2 10.255.255.22 [AS 1] 4 msec 0 msec 4 msec
>
> 3 10.13.0.253 [AS 65501] 4 msec 4 msec 0 msec
>
>
>
>
>
>
>
> > Subject: Re: BGP AS-PATH PREPEND
>
> > From: mothafungla_at_gmail.com
>
> > Date: Wed, 8 Jan 2014 15:59:21 +0000
>
> > CC: ccielab_at_groupstudy.com
>
> > To: ebay_products_at_hotmail.com
>
> >
>
> > Where's your match extended ACL in route-map condition ?
>
> >
>
> > --
>
> > BR
>
> >
>
> > Tony
>
> >
>
> > > On 8 Jan 2014, at 15:47, Cisco Fanatic <ebay_products_at_hotmail.com>
> wrote:
>
> > >
>
> > > I understand how AS-PATH PREPEND works, but I am not able to make it
> work
>
> if I
>
> > > need to manipulate traffic paths only from a specific source to a
>
> specific
>
> > > destination.
>
> > >
>
> > > R1
>
> > > ++
>
> > >
>
> > > !
>
> > > router bgp 65500
>
> > >
>
> > > neighbor 10.255.0.26 route-map AS_CHANGE out
>
> > >
>
> > > !
>
> > > route-map AS_CHANGE permit 10
>
> > >
>
> > > set as-path prepend 65500 65500 65500
>
> > >
>
> > > !
>
> > >
>
> > > R2
>
> > > ++
>
> > >
>
> > > !
>
> > > router bgp 65501
>
> > >
>
> > > neighbor 10.255.0.25 route-map AS_CHANGE out
>
> > >
>
> > > !
>
> > > route-map AS_CHANGE permit 10
>
> > >
>
> > > set as-path prepend 65501 65501 65501
>
> > >
>
> > > !
>
> > >
>
> > > R1#sh ip bgp
>
> > > BGP table version is 196, local router ID is 10.255.255.2
>
> > > Status codes: s suppressed, d damped, h history, * valid, > best, i -
>
> > > internal,
>
> > > r RIB-failure, S Stale, m multipath, b backup-path, x
>
> > > best-external, f RT-Filter
>
> > > Origin codes: i - IGP, e - EGP, ? - incomplete
>
> > > Network Next Hop Metric LocPrf Weight Path
>
> > > *> 10.3.0.0/16 0.0.0.0 0 32768 ?
>
> > > *> 10.7.0.0/24 0.0.0.0 0 32768 ?
>
> > > *> 10.11.0.0/24 0.0.0.0 0 32768 ?
>
> > > *> 10.13.0.0/16 10.255.255.1 0 1 65501 ?
>
> > > * 10.255.0.26 0 0 65501
> 65501
>
> 65501
>
> > > 65501 ?
>
> > > *> 10.16.0.0/24 0.0.0.0 0 32768 ?
>
> > > *> 10.20.0.0/24 10.255.255.1 0 1 65501 ?
>
> > > * 10.255.0.26 28416 0 65501
> 65501
>
> 65501
>
> > > 65501 ?
>
> > >
>
> > > I need specific traffic from 10.100.60.11 (Source) to specific
>
> 10.20.80.11
>
> > > (Destination) over the 10.255.0.26 connection.
>
> > >
>
> > >
>
> > > 10.100.60.11
>
> > > _` 10.20.80.11
>
> > >
>
> > >
>
> > > Any thoughts?
>
> > >
>
> > >
>
> > > Blogs and organic groups at http://www.ccie.net
>
> > >
>
> > > _______________________________________________________________________
>
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>
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>
> >
>
> >
>
> > Blogs and organic groups at http://www.ccie.net
>
> >
>
> > _______________________________________________________________________
>
> > Subscription information may be found at:
>
> > http://www.groupstudy.com/list/CCIELab.html
>
>
>
> Blogs and organic groups at http://www.ccie.net
>
>
> _______________________________________________________________________
>
> Subscription information may be found at:
>
> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
>
>
>
>

-- 
Marc Abel
CCIE #35470
(Routing and Switching)
Blogs and organic groups at http://www.ccie.net
Received on Wed Jan 08 2014 - 11:19:37 ART

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