05-09-2008 08:07 AM - edited 03-05-2019 10:52 PM
Hi all, kindly refer to this document
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a0080094309.shtml
now if i want this
If 192.168.50.0/24 exists in R102's BGP table, then do not advertise the 128.16.16.0/24 network to R101.
how can i accomplish this ? if i want to block advertisement of certain prefix when a particular prefix is in the BGP table then how can i do that ?
Thanks
05-09-2008 10:11 AM
Ovais,
This is exactly what the example does, as per comments in the configuration example:
!--- Advertises the routes matched in the route-map ADVERTISE (128.16.16.0/24)
!--- only if the routes matched in route-map NON-EXIST (192.168.50.0/24)
!--- do not exist in the BGP table.
So if 192.168.50.0/24 is present, 128.16.16.0/24 will not be advertised.
If you wanted the opposite (i.e. advertise 128.16.16.0/24 only when 192.168.50.0/24 is present) then you would use an exist-map instead of a non-exist-map.
Regards,
05-09-2008 10:16 AM
Try this. I'm not at a router to test but see if it works for you.
access-list 60 permit 128.16.16.0 0.0.0.255
access-list 65 permit 192.168.50.0 0.0.0.255
route-map EXIST deny 10
match ip address 65
route-map ADVERTISE permit 10
match ip address 60
neighbor 10.10.10.1 advertise-map ADVERTISE exist-map EXIST
Again, try this in a test environment as I didn't have a chance to test this myself.
05-09-2008 10:32 AM
Sparky,
This configuration would advertise 128.16.16.0/24 if 192.168.50.0/24 exists.
From the original poster:
"if i want to block advertisement of certain prefix when a particular prefix is in the BGP table:
Sounds like the opposite, right?
Regards,
05-09-2008 10:45 AM
I guess, I was just giving ideas.
05-09-2008 11:23 AM
hi guys, i got it done :) i was a bit confused but still did it, one thing for sure is that we cant use deny statements in any route-map ( advertise, exist and non-exist ) right ??
05-09-2008 02:08 PM
Ovais,
That is correct. You need to work either with the exist-map or non-exist-map but the trigger has to be done on a permit.
Regards,
05-09-2008 05:57 PM
Sparky,
Understood. Thanks for your contribution to NetPro.
Regards,
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: