How is the BGP network command different from the IGP network command?

• A. The network command does not start BGP on specific interfaces. It indicates to BGP which networks it should originate from the router.
• B. The network command starts BGP on all interfaces.
• C. IGP network command is used for BGP configuration.
• D. They are identical in function and scope.

Answer: (A)

In BGP, the network statement is about advertising networks that the router already knows how to reach. It does not turn BGP on for interfaces. Instead, you specify which prefixes (and their masks) should be originated into BGP, and BGP will advertise those networks only if they exist in the router’s local routing table (the RIB). If a listed network isn’t present in the RIB, BGP won’t originate it, because there’s nothing for BGP to advertise.

This contrasts with how IGP network statements work. In common IGPs like OSPF or EIGRP, the network command selects which interfaces participate in the IGP by matching their IP addresses against the given network/wildcard. It’s about enabling the protocol on those interfaces, not about advertising routes into the IGP.

So the correct idea is that the BGP network command tells BGP which networks to originate from the router, relying on the existing routes in the local routing table, rather than starting BGP on interfaces or serving the same role as an IGP network command.