A.All four routers are operating as Level 1-2 routers.

B.R1 and R4 are Level 2 neighbors.

C.All four routers are operating as Level 1 routers only.

D.R1 and R2 are Level 2 neighbors.

E.All four routers are operating as Level 2 routers only.

A.It enables the MPLS core to use EIGRP as the routing protocol.

B.It enables the Cisco MPLS TE tunnel to be advertised into the running IGP.

C.It enables the tailend router to advertise routes to the headend router over the tunnel.

D.It enables the headend and tailend routers to establish a bidirectional tunnel.

A.QoS policies use BGP to gain full coverage on the network.

B.QPPB policies affect only egress traffic

C.QoS policies are identified in the MPLS forwarding table

D.QoS policies rely exclusively on BGP attributes to manipulate traffic

A.IPv4 flow information

B.BGP AS information

C.IPv6 flow information

D.flow sequence numbers

A.PE-B(config-if)#ip ospf message-digest-key 1 md5 44578611
PE-B(config-if)#ip ospf authentication null

B.PE-B(config-if)#ip ospf message-digest-key 1 md5 44578611
PE-B(config-if)#ip ospf authentication key-chain 44578611

C.PE-B(config-if)#ip ospf message-digest-key 1 md5 44568611
PE-B(config-if)#ip ospf authentication null

D.PE-B(config-if)#ip ospf message-digest-key 1 md5 44578611
PE-B(config-if)#ip ospf authentication message-digest