A.It is used only for directly connected subnets or aggregate routes
B.It can only be used with LDP.
C.It is only used when two or more labels are stacked.
D.It enables the Edge LSR to request a label pop operation from Its upstream neighbors
E.It is requested through TDP using a special label value that is also called the implicit-null value.
F.It is requested through LDP using a special label value that is also called the implicit-null value.

A.prefixes received from any other BGP peer and prefixes locally originated via network statements or redistributed
B.all prefixes in its routing table
C.prefixes received from EBGP peers and prefixes locally originated via network statements or     redistributed
D.prefixes received from EBGP peers and prefixes received from route reflectors
E.prefixes received from other IBGP peers， prefixes received from EBGP peers，and prefixes redistributedto BGP
F.prefixes received from other IBGP peers and prefixes received from route reflectors

A.dropper
B.classifier
C.marker
D.querier
E.meter
F.shaper

A.data marked with DSCP AF21，VOIP marked with DSCP EF
B.data marked with DSCP AF51，VOIP marked with DSCP EF
C.data marked with the DE-bit. VOIP marked with the CLP-bit
D.data marked with DSCP EF，VOIP marked with DSCP AF31
E.data marked with IP precedence 5，VOIP marked with DSCP EF

A.mark VOIP traffic with IP precedence 6 and configure only fair-queue’ on the links
B.configure the scheduler allocate 3000 1000 command to allow the OoS code to have enough CPU   cycles
C.enable class-based traffic shaping on the VOIP traffic class
D.enable Layer 2 fragmentation and interleaving on the links
E.enable Frame Relay on the links and send voice and data on different Frame Relay PVCs

A.1） lowest root bridge id，2） lowest sender bridge id，3） lowest port id，4） lowest root path cost
B.1） lowest root path cost，2） lowest root bridge id，3） lowest sender bridge id，4） lowest sender port id
C.1） lowest root bridge id，2） lowest sender bridge id，3） lowest root path cost，4） lowest sender port id
D.1） lowest root bridge id，2） lowest root path cost，3） lowest sender bridge id，4） lowest sender port id

A.VTP updates are ignored and forwarded out all ports.
B.VTP updates are ignored and forwarded out trunks only.
C.VTP updates are made to the VLAN database and are forwarded out trunks only.
D.VTP updates are ignored and are not forwarded.

A.8192
B.16384
C.49152
D.65535

A.Designated Root Cost
B.bridge ID priority
C.max age
D.bridge ID MAC address
E.Designated Root Priority
F.forward delay

A.one global STP instance for all VLANs
B.one STP instance for each VLAN
C.one STP instance per set of VLANs
D.one STP instance per set of bridges