Which three statements about IS-IS are true? (Choose three.)
A.
IS-IS can be used only in the service provider network.
B.
IS-IS can be used to route both IP and CLNP.
C.
IS-IS has three different levels of authentication: interface level, process level, and domain level.
D.
IS-IS is an IETF standard.
E.
IS-IS has the capability to provide address summarization between areas.
B yes
C: between neighbors (interface), area-wide (process) and domain wide
D: ios 10589 but not ietf
E:summary-address address mask {level-1 | level-1-2 | level-2} is used to configure IP address summarization.