A.SLA responder knows type of operation， the port used， and duration.
B.SLA responder inserts in and out timestamps in the packet payload.
C.SLA sender and responder use the IP SLA Control Protocol to communicate with each other before
D.SLA sender and responder communication can be encrypted.
E.SLA sender and responder communication can be authenticated with MD5.

A.opaque LSA （Type 8）
B.opaque LSA （Type 9）
C.link LSA （Type 1）
D.network LSA （Type 2）
E.opaque LSA （Type 10）

A.MPLS is required between the ASBRs.
B.ASBR must hold all routing information.
C.It is a scalable solution.
D.It is a simple solution.
E.MP-EBGP is used to exchange routes between ASBRs.

A.general communication channel 0 （GCC0）
B.section monitoring
C.reserved （RES）
D.general communication channels 1 and 2 （GCC1 GCC2）
E.tandem connection monitoring activation deactivation （TCM ACT）

A.It is generated by an ASBR and indicates the reachability to an ABR located in another area.
B.It is generated by ABR and indicates the reachability to an ASBR located in another AS.
C.It is generated by ABR and indicates reachability to itself.
D.It is generated by ABR and indicates the reachability to an ASBR located in another area.
E.It is generated by ASBR and indicates the reachability to an ABR.