A.By perfornubg a show ip interface to see the type and source of the attack based upon the access-listmatches
B.By performing a show interface to see the transmitted load "txload" and receive load "rxload" ；if the interface utilization is not maxed out ，there is no attack underway
C.By setting up an access-list to permit all ICMP，TCP，and UDP traffic with the log or log-input commands，then use the show access-list and show log commands to determine the type and sourceof attack
D.By applying an access-list to all incoming and outgoing interfaces，turning off route-cache on all interfaces，then，when telnetting into the router perform a debug IP packet detail

A.LDP hello packets are sent to UDP port 646
B.LDP hello packets are sent to TCP port 711
C.LDP sessions are TCP sessions to port 646
D.LDP sessions are TCP sessions to port 711
E.LDP establishes a peer relationship with another router that must be directly attached
F.LDP can establishes a peer relationship with another router that is not directly attached