A.SNMP version 2 uses a proxy agent to forward GetNext message to SNMP version 3.
B.SNMP version 2 supports message integrity to ensure that a packet has not been tampered with
C.Proxy agents were used only in SNMP version 1.
D.SNMP version 3 supports encryption and SNMP version 2 support authentication.
E.GetBulk messages are converted to GetNext messages by the proxy agent and are then forwarded to the SNMP version 1 agent.

A.Default MDT groups are used for PIM control traffic， low-bandwidth sources， and flooding of sparse mode traffic.
B.MDTs are built in customer networks
C.Data MDT groups are used for high-bandwidth sources to reduce replication to uninterested PEs.
D.MDTs are built in provider networks
E.The number of MDTs depends on PIM modes of MDT groups.

A.AAL2
B.AAL 4
C.AL 5
D.AAL 1
E.AAL 3

A.Policy-based Model
B.Class based Model
C.Russian Doll Model
D.Global Tunnel Model
E.Maximum Allocation Model

A.switched virtual circuit
B.virtual circuit status
C.simple flow control
D.multicasting
E.permanent virtual circuit

A.EBGPv4 with a sending community
B.IGP and LDP
C.EBGPv4 with a sending label
D.IGP and EBGPv4
E.IGP and RSVP

A.8 rows by 64 bytes
B.6 rows by 64 bytes
C.10 rows by 96 bytes
D.8 rows by 128 bytes
E.9 rows by 90 bytes

A.10 minutes
B.5 minutes
C.120 seconds
D.60 seconds
E.30 minutes

A.fast convergence SFP
B.MTU discovery
C.redundancy links
D.keepalive
E.carrier delay

A.IPsec tunnel
B.routing equivalence paths
C.traffic engineering tunnel
D.bridge or switch instance
E.groups of IP addresses