Which two statements are true about IS-IS adjacency formation? (Choose two.)
A.
Level 1 only routers never form an adjacency with Level 2 only routers.
B.
Level 1 only routers always form an adjacency with Level 2 only routers.
C.
For Level 1 adjacencies, area IDs must be the same.
D.
For Level 2 adjacencies, area IDs must be the same.
Explanation:
An L1 router does not form an adjacency with an L2 router, regardless of area.
L1 routers form L1 adjacencies with L1 and L1-L2 routers in their area.
L2 routers form L2 adjacencies with L2 and L1-L2 routers in their area or another area.
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