多选题Which two are valid IS-IS PDU types？（）Abroadcast hellosBLevel 1 LAN hellosCPoint-to-point hellosDLevel 2 point-to-point hellos
题目
多选题
Which two are valid IS-IS PDU types？（）
A
broadcast hellos
B
Level 1 LAN hellos
C
Point-to-point hellos
D
Level 2 point-to-point hellos