Cisco eBGP (External) Protocol
Network Topology
As of Cisco Packet Tracer 8.2 internal BGP (iBGP) is not supported only external BGP (eBGP) is supported. If you try and configure iBGP on Packet Tracer, you will see the following message.
So, in this example the focus will be on setting up eBGP between two separate autonomous systems.
Router0 Configuration Commands
Router0>enable
Router0#configure terminal
Router0(config)#interface serial 0/0/0
Router0(config-if)#ip address 172.16.1.1 255.255.255.248
Router0(config-if)#no shutdown
Router0(config-if)#interface gigabitEthernet 0/0
Router0(config-if)#ip address 192.168.10.1 255.255.255.0
Router0(config-if)#no shutdown
Router0(config-if)#int Loopback 0
Router0(config-if)#ip address 1.1.1.1 255.0.0.0
Router0(config-if)#no shutdown
Router0(config-if)#exit
Router0#router bgp 65001
Router0(config-router)#neighbor 172.16.1.2 remote-as 65002
Router0(config-router)#network 1.1.1.1 mask 255.0.0.0
Router0(config-router)#network 192.168.10.0 mask 255.255.255.0
Router0(config-router)#no synchronization
Router1 Configuration Commands
Router1>enable
Router1#configure terminal
Router1(config)#interface serial 0/0/0
Router1(config-if)#ip address 172.16.1.2 255.255.255.248
Router1(config-if)#no shutdown
Router1(config-if)#interface gigabitEthernet 0/0
Router1(config-if)#ip address 192.168.20.1 255.255.255.0
Router1(config-if)#no shutdown
Router1(config-if)#int Loopback 0
Router1(config-if)#ip address 2.2.2.2 255.0.0.0
Router1(config-if)#no shutdown
Router1(config-if)#exit
Router1#router bgp 65001
Router1(config-router)#neighbor 172.16.1.1 remote-as 65001
Router1(config-router)#network 2.2.2.2 mask 255.0.0.0
Router1(config-router)#network 192.168.20.0 mask 255.255.255.0
Router1(config-router)#no synchronization
A Special Word about the No Synchronization Command
The site BGPExpert has an excellent explanation of what the no synchronization command is and what is does.
Check BGP Configuration
Router0#show ip route
Router0#show ip bgp summary
Router0#show ip bgp
Ping and Tracert Connectivity Tests
