[AUDIO LOGO]
Congratulations on completing another skill.
Now, it's time for a review in the form of a quiz.
So let's go ahead and jump in with our first question.
When you enable IS-IS Prefix suppression,
which of the following will be advertised into IS-IS?
So let's go ahead and go down our list.
Our first answer number one is loopback interfaces.
Now, that's actually something that happens in OSPF,
but that is not something that happens in IS-IS.
So loopback interfaces is an incorrect answer.
Number two is transit links.
Well, honestly, this would defeat the entire purpose
of prefix suppression.
So number two is actually the opposite
of what would be advertised.
Number three is passive interfaces.
These, of course, will be advertised.
That's why the command is advertise passive
only because only passive interfaces will get advertised.
Of course, if answer three correct,
then answer four can't be correct because they're
mutually exclusive.
So in this case, our correct answer
is number three, passive interfaces.
Next question.
Which of the following is the default behavior
of IS-IS regarding route propagation?
So the first thing to discuss here
is that we are talking about the default behavior,
not what you as an administrator can
control because we know that you can control route leaking.
So what does it do by default?
Number one says that it will leak routes from Level 2
to Level 1.
That is not correct.
By default, all Level 2 prefixes are blocked
from going into Level 1.
Remember that it instead generates
a default. Number two, it will block routes from Level 2
to Level 1.
Well, that is what we just said.
So yes, two is a correct answer.
Number three, it will block routes from Level 1 to Level 2.
This is actually not correct.
In fact, it will actually leak them.
So at the same time that we mark three as an incorrect answer,
it does mean that five becomes our correct answer because it's
saying that it will leak the routes from Level 1 to Level 2.
Now, four and six here, if we look at them,
are sort of, again, exclusive if these other answers
were correct.
It will leak all routes between levels.
Well, no, we just established that's not the case.
And number six, it will block all routes between levels.
Again, we just established that that's not correct either.
So the correct answer to the default behavior
is it will block routes from Level 2 to Level 1,
and it will leak routes from Level 1 to Level 2.
So two and five are the correct answers.
Final question.
What two elements can be authenticated in IS-IS?
So this is simply a matter of remembering the two things
that we can authenticate in IS-IS are the IS-IS hellos
and the LSPs or the exchanging of the database itself.
Once again, we can use either plaintext or MD5
for either one of these.
They can use the same key chain or different key chains.
So we have some flexibility here.
And of course, we can enable just one
of these or the other one or both or, well, neither,
although that's not generally recommended.
But these are the two things that can be authenticated.
So that concludes this quiz.
If you feel that you are missing any of the elements needed
to answer these questions, I would
encourage you to go back and review the reference
sources on each question.
Otherwise, congratulations on completing Implementing IS-IS
Advanced Features.
I hope this has been informative for you.
And I'd like to thank you for viewing.