Lab 95 - BGP Path Selection using Weight

Prerequisites: CCNP level skills.

Topology

Note!

All routers are configured as per topology diagram (pic. 1) and loopback advertised into BGP.

Pic. 1 - Topology Diagram.

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

Task 1
On R2, manipulate paths using weight attribute so it chooses R4 as the gateway to:

• 172.16.101.0/24
• 172.16.105.0/24

Lab Solution

Task 1

On R2, manipulate paths using weight attribute so it chooses R4 as the gateway to:

• 172.16.101.0/24
• 172.16.105.0/24

Pic. 2 - BGP Table on R2 Before Change.

R2 Configuration:

!

ip prefix-list CHANGE seq 5 permit 172.16.101.0/24
ip prefix-list CHANGE seq 10 permit 172.16.105.0/24
!

route-map SET_WEIGHT permit 10
 match ip address prefix-list CHANGE
 set weight 50
!
router bgp 20
 no synchronization
 bgp router-id 172.16.102.2
 bgp log-neighbor-changes
 network 172.16.102.0 mask 255.255.255.0
 neighbor 10.1.23.3 remote-as 13
 neighbor 10.1.24.4 remote-as 40
 neighbor 10.1.24.4 route-map SET_WEIGHT in
 no auto-summary

!

Notice!
For this change to take effect 'clear ip bgp * in' ('*' or the neighbor in question).

Pic. 3 - BGP Table on R2 After Change.