Lab 115 - BGP Communities - NO-ADVERTISE

Prerequisites: CCNP level skills.

BGP Default Communities

• internet - Advertise this route to the Internet community. All routers belong to it.
• no-export - Do not advertise this route to eBGP peers (real BGP peers).
• no-advertise - Do not advertise this route to any peer (internal or external).
• local-as - Do not advertise this route to peers outside the local autonomous system. This route will not be advertised to other autonomous systems or sub-autonomous systems when confederations are configured.

source:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfbgp.html#wp1001855

Notice!
AS 13 is a confederation autonomous system. It has two sub-autonomous systems: 65001 and 65003.

Topology

Pic. 1 - Topology Diagram.

Icons designed by: Andrzej Szoblik - http://www.newo.pl

Task 1 
R5 is advertising 172.16.105.0/24 into BGP. Use the BGP community so that R3 does not advertise it any further.

Solution

Task 1 
R5 is advertising 172.16.105.0/24 into BGP. Use the BGP community so that R3 does not advertise it any further.

R5 Configuration:

!
ip prefix-list LOOPBACK0 seq 5 permit 172.16.105.0/24

!

route-map SET_COMMUNITY permit 10
 match ip address prefix-list LOOPBACK0
 set community no-advertise
!
route-map SET_COMMUNITY permit 999
!
router bgp 50
 no synchronization
 bgp router-id 172.16.105.5
 bgp log-neighbor-changes
 network 172.16.105.0 mask 255.255.255.0
 neighbor 10.1.35.3 remote-as 13
 neighbor 10.1.35.3 send-community
 neighbor 10.1.35.3 route-map SET_COMMUNITY out
 no auto-summary

!

Verification:

Pic. 2 - BGP Prefix on R3.