A.Filter Smurf ICMP packets.
B.Filter as close to the core as possible
C.Filter as close to the edge as possible
D.Filter as precisely as possible
E.Filter both source and destination where possible

A.Two LSAs will exist in the network for this destination， and both will be used
B.Two LSAs will exist in the network for this destination， but only the one generated by the highest RID ASBR will be used
C.Only the LSA generated by the highest RID ASBR will exist in the network
D.Only the LSA generated by the lowest RID ASBR will exist in the network

A.standby 1 priority 110
B.standby 1 priority 120
C.standby 1 priority 130
D.standby 1 priority 110 preempt
E.standby 1 priority 120 preempt
F.standby 1 priority 130 preempt

A.A sham-link is created between any twoo VPN sites that belong to the same OSPF area and share an OSPF backdoor link
B.A sham-link is seen as an intra-area link between PE routers，an OSPF adjacency is created and data base is exchanged
C.A SHAM link is created between two directly connected PE routers so that it is preferred over the low speed backdoor door
D.A SHAM link is part of OSPF network of MPLS-VPN provider

A.AS numbers are assigned by the IANA
B.AS numbers are used by BGP （Border Gateway protocol ） to exchange IP routing information with neighboring AS
C.In the internet， an Autonomous System （AS） is a collection of IP networks and routers under the control
D.All of the Above