— BGP: network A.B.C.D/M

This command adds the announcement network.

          router bgp 1
           network 10.0.0.0/8
     

This configuration example says that network 10.0.0.0/8 will be announced to all neighbors. Some vendors' routers don't advertise routes if they aren't present in their IGP routing tables; bgp doesn't care about IGP routes when announcing its routes.

— BGP: no network A.B.C.D/M