A.one primary and one secondary IP address
B.one IP address
C.as many IP addresses as you want
D.one primary and multiple secondary IP addresses

A.It is only used for exception traffic.
B.It is an FE link called fxp2.
C.It is rate-limited to avoid DDOS attacks.
D.It is only used to send the forwarding-table from the Routing Engine to the Packet-Forwarding Engine.