Configuration Steps

Step 1: Configure hostnames and IP addresses on interfaces as follows.

***************************R1
sys
sysname R1
#
interface GigabitEthernet0/0/0
 ip address 10.10.0.2 255.255.255.0
#
interface LoopBack0
 ip address 1.1.1.1 255.255.255.255
#

***************************R2
sys
sysname R2
#
interface GigabitEthernet0/0/0
 ip address 10.10.1.2 255.255.255.0
#
interface LoopBack0
 ip address 2.2.2.2 255.255.255.255
#

*****************************R3
sys
sysname R3
#
interface GigabitEthernet0/0/0
 ip address 10.10.0.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 ip address 10.10.1.1 255.255.255.0
#
interface GigabitEthernet0/0/2
 ip address 10.20.2.1 255.255.255.0
#
interface GigabitEthernet0/0/3
 ip address 10.20.3.1 255.255.255.0
#
interface LoopBack0
 ip address 3.3.3.3 255.255.255.255
#

***************************R4
sys
sysname R4
#
interface GigabitEthernet0/0/0
 ip address 10.20.2.2 255.255.255.0
#
interface LoopBack0
 ip address 4.4.4.4 255.255.255.255
#

***************************R5
sys
sysname R5
#
interface GigabitEthernet0/0/0
 ip address 10.20.3.2 255.255.255.0
#
interface LoopBack0
 ip address 5.5.5.5 255.255.255.255
#

Step 2: Configure Dynamic BGP on R3 as follows.

******************************R3
bgp 100
bgp dynamic-session-limit 10
group INTERNAL listen internal
peer INTERNAL listen-net 10.10.0.0 16
group EXTERNAL listen external
peer EXTERNAL listen-as 200
peer INTERNAL listen-net 10.20.0.0 16
#

Step 3: Configure BGP connections on R1, R2, R4 and R5.

**********************R1
bgp 100
 router-id 1.1.1.1
 peer 10.10.0.1 as-number 100
 #
 ipv4-family unicast
  peer 10.10.0.1 enable
#

**********************R2
bgp 100
 router-id 2.2.2.2
 peer 10.10.1.1 as-number 100
 #
 ipv4-family unicast
  peer 10.10.1.1 enable
#

**********************R4
bgp 200
 router-id 4.4.4.4
 peer 10.10.2.1 as-number 100
 #
 ipv4-family unicast
  peer 10.10.2.1 enable
#

**********************R5
bgp 200
 router-id 5.5.5.5
 peer 10.10.3.1 as-number 100
 #
 ipv4-family unicast
  peer 10.10.3.1 enable
#

Step 4: Verification

Verify the BGP peering status by running the “display bgp peer” command on all routers. On R3 run the commands “display bgp group INTERNAL” and “display bgp group EXTERNAL” to verify the status of the dynamic groups.