To begin configuring a BGP process, issue the following familiar command:
Router(config)#router BGP AS-number
In BGP, the network command tells the BGP process what locally learned networks to advertise
Router (config-router) #network network-number [mask network-mask]
For a BGP router to establish a neighbor relationship with another BGP router, issue the this configuration command:
Router (config-router) #neighbor IP-address remote-as AS-number