Which two statements about IS-IS are true? (Choose two.)
A. The default hello interval is 10 seconds and the default hold timer is 30 seconds.
B. The hello interval can be changed on a per-interface basis with the command isis hello- multiplier.
C. Both routers need to have the same hello intervals and hold timers in order to form IS-IS neighbors.
D. Both IS-IS routers need to have the same capabilities in the hello packet in order to form neighbors.
But the hello-interval is NOT the hello-multiplier. Question B clearly states hello-multiplier.
is-is hellos do NOT have to match
Correct answers A,D
B is not correct. The hello interval isn’t changed by the hello-multiplier. It changes the amount of times the hello can be missed for it considers the adjacency down. (therefore it sets the hold time).
The hello timer is set using “isis hello-interval [level-1 | level-2]”
C is neither correct.
D could be true, but it to broad. Some capabilities need to match for the link to come up. Details can be found here: https://www.cisco.com/c/en/us/support/docs/ip/integrated-intermediate-system-to-intermediate-system-is-is/200293-IS-IS-Adjacency-and-Area-Types.html
B is correct because:
isis hello-interval minimal :
If the minimal keyword is specified, the hold time is 1 second and the system computes the hello interval based on the hello multiplier.