RE: BGP AS-PATH PREPEND

How are you advertising the host route for 10.20.80.11? I don't see a route
for "10.20.80.11" in your BGP table. Are you doing it via a network
statement on the router you're showing the route-map on? In order to
manipulate a route you need to be advertising it.

Jeffrey Lodwick - CCIE 15671 R&S
Senior Data Engineer / Owner
Jeff_at_tydesystems.com
Office: 303-346-9988
Mobile: 303-919-1366

www.tydesystems.com

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Cisco Fanatic
Sent: Wednesday, January 08, 2014 9:54 AM
To: Sam Bibby
Cc: Tony Singh; ccielab_at_groupstudy.com
Subject: RE: BGP AS-PATH PREPEND

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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Received on Wed Jan 08 2014 - 10:36:47 ART