BGP

• Configure a route policy (at least a pass-all RPL).
• Configure BGP with the ASN and networks to be advertised::

RP/0/0/CPU0:router(config)# router bgp 65535 RP/0/0/CPU0:router(config-bgp)# address-family ipv4 unicast RP/0/0/CPU0:router(config-bgp-af)# network 192.0.2.0/24

• Configure the neighbor::

RP/0/0/CPU0:router(config-bgp)# neighbor 172.31.0.5 RP/0/0/CPU0:router(config-bgp-nbr)# remote-as 65533 RP/0/0/CPU0:router(config-bgp-nbr)# update-source Looback0 RP/0/0/CPU0:router(config-bgp-nbr)# address-family ipv4 unicast RP/0/0/CPU0:router(config-bgp-nbr-af)# route-policy pass-all in RP/0/0/CPU0:router(config-bgp-nbr-af)# route-policy pass-all out

• Commit the configuration

Further customization is possible via route policies.