A.A value of 4 represents the "Implicit NULL Label."
B.A value of 0 represents the "IPv4 Explicit NULL Label."
C.A value of 1 represents the "Router Alert Label". The use of this label is analogous to the use of the"Router Alert Option" in IP packets （for example， ping with record route option）
D.A value of 2 represents the "IPv6 Explicit NULL Label"
E.A value of 1 represents the "IPv1 Explicit NULL Label"
F.A value of 3 represents the "Implicit NULL Label"

A.it uses multicast address 224.0.0.10，instead of broadcast
B.it uses multicast address 224.0.0.9，instead of broadcast
C.it can use either multicast or broadcast addresses，instead of just broadcast
D.it sends incremental updates，instead of periodic updates
E.it is classless，instead of classful
F.it supports authentication，and RIPv1 does not

A.IBGP updates exchange between trigger router and black hole router
B.EBGP updates exchange between trigger router and black hole router
C.OSPF updates exchange between trigger router and black hole router
D.ISIS updates exchange between trigger router and black hole router

A.The MD5 algorithm inputs the routing updates of arbitrary length and outputs a 128-bit hash
B.The MD5 algorithm inputs the routing updates of every 64bit length and outputs an 8-bit hash
C.Multiple keys are supported
D.Routing updates packets are delivered in encrypted messages
E.Shared secret keys are delivered in encrypted messages

A.Prevents head-of-line blocking
B.Uses less memory
C.Increases forwarding performance
D.Simplifies configuration

A.Inserted between the MPLS label stack and the Layer 3 payload
B.Inserted between the MPLS label stack and the Layer 3 Header
C.Inserted between the MPLS label stack and the Layer 2 payload
D.Inserted between the MPLS label stack and the Layer 2 header

A.BGP route-reflector should be in forwarding path of data coming from its clients
B.BGP route-reflector does not have to be in the forwarding path of data coming from its clients
C.BGP route-reflector will stop reflecting the routes if they’re not directly-connected clients
D.None of the above

A.Failure detection
B.Failure reporting
C.IGP LSP/LSA originatio
D.Per-hop flooding time of new link state
E.Number of hops that need to be notified of new link state

A.MPLS LDP must be enabled.
B.BGP routing protocol must be running.
C.Named access-lists must be configured.
D.Symmetrical routing is required.
E.Domain name must be defined

A.Allows incoming TCP connections destined to port 179
B.Allows incoming TCP connections sourced from port 179
C.Allows incoming TCP connections from 1.1.1.1 and destined to，or sourced from port 179
D.Allows incoming TCP connections from 1.1.1.1 that are destined to port 179
E.Allows incoming TCP connections from 1.1.1.1 that are sourced from port 179