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[isp-bgp] Advertising in BGP
Hello all
I have a network constituted with 2 routers (R1 and R2)connected on
iBGP, and each router is connected in eBGP to ISPs (ISP1 and ISP2). I'm
trying to manage incoming traffic of routes advertised by my AS with
prefix and route-map with as-prepend as following and it work well, see
configuration:
On R1
=====
router bgp MyAS
.....
neighbor Loopback0 remote-as ISP1
neighbor Loopback0 route-map ISP1-IN in
neighbor Loopback0 route-map ISP1-OUT out
!
ip as-path access-list 2 permit ^$
!
ip prefix-list TO-R2 seq 10 permit network1/24 le 32
ip prefix-list TO-R2 seq 15 permit network2/24 le 32
ip prefix-list TO-R2 seq 20 permit network3/24 le 32
!
route-map ISP1-OUT permit 20
match ip address prefix-list TO-R2
match as-path 2
set as-path prepend MyAS MyAS
!
route-map ISP1-OUT permit 30
match as-path 2
On R2
========
router bgp MyAS
.....
neighbor Loopback0 remote-as ISP2
neighbor Loopback0 route-map ISP2-IN in
neighbor Loopback0 route-map ISP2-OUT out
!
ip as-path access-list 2 permit ^$
!
ip prefix-list TO-R1 seq 10 permit network4/24 le 32
ip prefix-list TO-R1 seq 15 permit network5/24 le 32
ip prefix-list TO-R1 seq 20 permit network6/24 le 32
!
route-map ISP2-OUT permit 20
match ip address prefix-list TO-R1
match as-path 2
set as-path prepend MyAS MyAS
!
route-map ISP2-OUT permit 30
match as-path 2
My question is if I add route on both Prefix-list, for example:
On R1:
======
ip prefix-list TO-R2 seq 10 permit network1/24 le 32
ip prefix-list TO-R2 seq 15 permit network2/24 le 32
ip prefix-list TO-R2 seq 20 permit network3/24 le 32
On R2:
======
ip prefix-list TO-R1 seq 10 permit network4/24 le 32
ip prefix-list TO-R1 seq 15 permit network5/24 le 32
ip prefix-list TO-R1 seq 20 permit network6/24 le 32
ip prefix-list TO-R2 seq 20 permit network3/24 le 32
What should happen on advertising ?
Thanks for any answer
Jacques VUVANT
Network OPT New-Caledonia
Phone : +687-267541
Fax : +687-278444
Mob : +687-773121
Mail : Jacques.vuvant@...
-----Message d'origine-----
De : Carl-Henrik Landgren [mailto:landgren@...
Envoyé : mercredi 16 juillet 2003 23:19
À : isp-bgp@isp-bgp.com
Cc : isp-bgp@isp-bgp.com
Objet : [isp-bgp] RE: Sample BGP Config
Depending on what link you want the traffic to take, it's pretty
simple....
Just make the link you don't want the outbound traffic to pass with a
longer AS-PATH, just add your own AS to the AS-SEQUENCE several times to
make it long enough.
Or, you can filter with LOCAL-PREF for the prefixes you want the
outbound-traffic to exit your AS.
The rest i assume you know how to configure yourself.
/Carl
------- Ursprungligt brev -------
Från: chris@...
Datum: Tue, 15 Jul 2003 14:58:48 -0700
Michael,
Thanks for the response. The example I read was "Load Sharing when
Multihomed to Two ISPs via Multiple Local Routers"
The outbound traffic policy in this example limits traffic to one of the
two providers unless there is a failure.
The outbound traffic policy is as follows:
Traffic destined to AS 300 goes via the R1 - ISP(A) link.
Traffic destined to AS 400 goes via the R2 - ISP(B) link.
All other traffic should prefer default route 0.0.0.0 via the R1 -
ISP(A) link.
If the R1 - ISP(A) link fails, all traffic should go via the R2 - ISP(B)
link.
I'd like to have outbound traffic take the shortest path if both ISP's
are up and fail over to the other ISP if one ISP link fails.
Christopher J. Wolff, VP CIO
Broadband Laboratories, Inc.
http://www.bblabs.com
-----Original Message-----
From: Michael Weinstock [mailto:MWeinstock@...Sent: Tuesday, July 15, 2003 2:50 PM
To: isp-bgp@isp-bgp.com
Subject: [isp-bgp] RE: Sample BGP Config
Hello,
You didnt like it? Perhaps specify what you didnt like... As the answer
will be based on Cisco's docs.
-----Original Message-----
From: Christopher J. Wolff [mailto:chris@...Sent: Wednesday, 16 July 2003 9:47 a.m.
To: isp-bgp@isp-bgp.com
Subject: [isp-bgp] Sample BGP Config
Hello,
I'm looking for a couple of sample cisco configs that illustrate two
multihomed routers connected by an IGP session. For example;
Router 1----------Isp 1
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IGP
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Router 2----------Isp 2
I read the Cisco scenarios for multihomed networks documents but I
didn't like what I read. Thank you in advance.
C.J. Wolff, VP CIO
Broadband Laboratories, Inc.
http://www.bblabs.com
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- Replies
-
- [isp-bgp] Re: Advertising in BGP, Jeffrey Belles
- Replies
-
- [isp-bgp] RE: Sample BGP Config, Carl-Henrik Landgren
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