RE: conditional default advertising in BGP with multiple routes

From: Simon Grace (SimonG@pcsystems.gr)
Date: Wed Oct 17 2007 - 06:28:00 ART

I posted a question concerning all of this before I read this one.
Sorry.

Answers my question exactly, Good work Dazzler.

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Darren Johnson
Sent: Wednesday, October 17, 2007 11:00 AM
To: Koen Zeilstra; ccielab@groupstudy.com
Subject: Re: conditional default advertising in BGP with multiple routes
to monitor

Hey there. There is a much easier way using 'neighbor advertise-maps',
check it out here:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hi
rp_r/rte_bgh2.htm#wp1071377

Yours would be something like:

router bgp x
neighbor x.x.x.x advertise-map DEFAULTROUTE exist-map MATCHINGROUTES

route-map DEFAULTROUTE permit
match ip address prefix-list thedeaultroute

route-map MATCHINGROUTES permit
match ip address prefix-list matchroutes

ip prefix-list thedefaultroute permit 0.0.0.0/0

ip prefix-list matchroutes permit 10.1.1.0/24
ip prefix-list matchroutes permit 192.168.4.0/24

This is saying that if 10.1.1.0 AND 192.168.4.0 are in the routing
table, advertise out the default route. This is known as BGP
conditional-advertisements....

Hope this helps

Dazzler

----- Original Message ----
From: Koen Zeilstra <koen@koenzeilstra.com>
To: ccielab@groupstudy.com
Sent: Tuesday, 16 October, 2007 10:13:33 AM
Subject: conditional default advertising in BGP with multiple routes to
monitor

Hi Group,

Please observe the following (I hope) interesting task.

Advertise a default route to a BGP neighbor conditionally. Watch two
routes in your routing table. When both routes are present the default

route should be announced to the neighbor.

I was thinking towards the following direction.

neighbor 10.0.0.1 default-originate route-map checkroutes
!
route-map checkroutes
  match ip address 10
  match ip address 20
!
access-list 10 permit 1.1.1.1
access-list 20 permit 2.2.2.2
!

However this route-map results in:

route-map checkroutes
  match ip addres 10 20
!

Which is an "OR" function afterall and not the "AND" we are looking for.

Any bright ideas on this particular assignment?

thanks in advance,

Koen

This archive was generated by hypermail 2.1.4 : Fri Nov 16 2007 - 13:11:15 ART