[AUDIO LOGO]
Congratulations on completing another skill.
Now it's time for a review in the form of a quiz.
Let's jump in with our first question.
If you enable area 0 authentication
but do not provide a key for the virtual link,
what will happen on IOS XE?
So one of our keys here, of course,
is that we are, in fact, talking about IOS XE.
Keep that in mind.
And of course, the question is, what
happens if we don't provide a key on the actual virtual link?
So what are our choices here?
Well, we have number one says, the virtual link
will come up using default key 0.
That actually sounds correct.
Let's hold on to that for a minute
and look at the other answers.
Number two says, the virtual link
will come up by using default key 1.
Now, if you remember, when we were configuring this,
we were using key 1.
So there's not a default key 1.
There's just the one we created.
So that would make two an incorrect answer, because there
is no default key 1.
Answer number three says that the virtual link will come up
without authentication.
Now, if you remember, this is actually what IOS XR did.
But we're talking about IOS XE.
So this would be incorrect for IOS XE.
Number four, the virtual link will not come up.
By the way, this is the answer I would prefer.
I would actually prefer that the virtual link did not come up.
Sadly, however, this is not the case.
The virtual link in fact will come up.
And as answer one says, it will come up using a default key 0.
So in this case, that makes answer one the correct answer.
Next question, if you configure OSPF
timers using the following command, what will
be the resulting Hello timer?
ip ospf dead-interval minimal hello-multiplier 4.
So this is fairly straightforward
if we remember what these things do.
Minimal simply means that it will be 1 second.
But remember that the minimal here is
referring to the dead-interval.
You then set the Hello multiplier.
And in this case, we're setting it to 4.
This simply means that we're going
to send four times Hellos, because again, this
is going with the Hellos, per every dead interval.
So if we're going to send four Hellos in 1 second
and 1 second, of course, is 1,000 milliseconds,
we divide this by 4.
This is going to be 250 milliseconds.
Therefore, our correct answer is going
to be three, 250 milliseconds.
No need to go down the list here since it's just math.
Final question, which of the following
is provided using OSPF MD5 authentication?
Now, of course, the big key to this
is to remember that the MD5 is--
well, it's providing authentication.
So let's go down our list.
Does authentication provide data integrity?
That would generally be something
like a hash, something like that would verify
the data has not been changed.
And the answer is no, it does not.
Does it provide LSA validation?
Not directly.
You could possibly make an argument
that two could be correct just simply
because I won't take an LSA from a nonvalid neighbor.
But it's certainly not doing LSA validation itself.
And we sort of just gave away number three
that what it does do is neighbor validation.
It makes sure that you will only neighbor up with the routers
that you intend to neighbor up with.
Does it give data privacy, which would probably normally
be referred to as encryption?
And the answer is no, not in OSPF using MD5 authentication.
We do not get encryption or data privacy.
And nothing about this gives us compression.
So number five, LSA compression, no, this just isn't something
that we provide.
So this means that our answer for this question
is number three.
So that concludes this quiz.
If you feel you were missing any of the information needed
to answer any of these questions,
I would encourage you to go back and review
the sources referenced on the bottom of each question.
Otherwise, congratulations on completing Authentication,
Virtual Links, and Optimization.
I hope this has been informative for you,
and I'd like to thank you for viewing.