Cisco Exam Questions

Why is the neighbor relationship between R2 and R4 shown as ES-IS?

Refer to the exhibit.

Why is the neighbor relationship between R2 and R4 shown as ES-IS?

A.
because there is an MTU mismatch between R2 and R4

B.
because interface S3/0 of R4 is configured as L1/L2

C.
because interface S3/0 of R2 is configured as L1

D.
because there is a hello interval mismatch between R2 and R4

Explanation:
We see ES-IS when either one side is configured to send only L2 and another side is configure to
send L1. In this case both sides show each-other as ES-IS. However, from the diagram we see that
one side is sending L1 and L2. We also can see ES-IS when we have MTU Mismatch