RouterB(config-router)#neighbor 10.1.1.2 remote-as
64520
RouterB(config-router)#neighbor 192.168.1.50
remote-as 65000
RouterB(config-router)#network 172.16.10.0
mask 255.255.255.0
RouterB(config-router)#network 192.168.1.0
mask 255.255.255.0
RouterB(config-router)#no synchronization
RouterB(config-router)#neighbor 192.168.1.50
next-hop-self
RouterB(config-router)#aggregate-address 172.16.0.0
255.255.0.0 summary-only