A.Access attacks can consist of password attacks，trust exploitation，port redirection，and man-in-the-middle attacks.
B.Access attacks can consist of UDP and TCP SYN flooding，ICMP echo-request floods，and ICMP directed broadcasts.
C.DoS attacks can be reduced through the use of access control configuration，encryption，and RFC 2827 filtering.
D.DoS attacks can consist of IP spoofing and DDoS attacks.
E.IP spoofing can be reduced through the use of policy-based routing.
F.IP spoofing exploits known vulnerabilities in authentication services， FTP services，and web services to gain entry to web accounts，confidential databases，and other sensitive information.

A.Labeled packets can be sent over an interface.
B.MPLS Layer 2 negotiations have occurred.
C.IP label switching has been disabled on this interface.
D.None of the MPLS protocols have been configured on the interface.