Which of the following causes may result in an IS-IS neighbor relationship fault? (Choose all that apply.)
Which of the following causes may result in an IS-IS neighbor relationship fault? (Choose all that apply.)
Several issues can prevent an IS-IS neighbor relationship from being established correctly: if the devices on two ends of a link have the same system ID (A), if they have inconsistent IS-IS levels (B), and if they have inconsistent area addresses when establishing a Level-1 neighbor relationship (C). Option D is irrelevant because IS-IS operates at the data link layer and does not depend on IP addresses.
A,B and C
A and B