[AUDIO LOGO]
Hello, and welcome to configuring
route redistribution.
In this skill, we're going to be taking a look
at the process of moving routes from one routing protocol
to another, otherwise known as redistribution.
Now, we're going to be focusing on the IGPs
or the interior gateway protocols in this skill.
And the simple reason for that is we'll
be doing plenty of redistribution
with BGP in our MPLS skills later in the course.
So we'll be getting plenty of practice with BGP.
Overall, the process is pretty much the same either way.
So for the IGPs, we will be looking at OSPF, IS-IS.
And we'll actually look at RIP and EIGRP
in this skill just for completeness.
Now, our main focus is going to be
what are the different caveats of redistributing routes
into each of the different protocols.
And they each do have their own little caveats.
So we're going to take a look at that.
And we're also going to take a look
at how we handle things like metrics, which we know
from using administrative distance,
are not comparable between routing protocols.
Admin distance exists just because they're not.
That way, we don't have to try to compare an OSPF route
to a RIP route, for example.
Admin distance just says to prefer the OSPF route.
It doesn't try to compare these two things that are
very different-- the metrics.
Well, when it comes to redistribution,
we have a similar problem.
We can't exactly take an OSPF metric, which is based on cost,
and put that into RIP, which is based on hop count.
And the numbers completely wouldn't match up.
So these are some issues we have to deal with.
We also have to deal with the fact
that as soon as you go between two different IGPs, well,
you'll lose the loop prevention that's inherent to that IGP.
All of these protocols have their own unique loop
prevention mechanisms--
things like split horizon, and route poisoning,
and all sorts of things.
And of course, OSPF and IS-IS, both
being link state protocols, they're
naturally, inherently preventing loops.
However, when you start going between areas,
they have their methods as well.
But all of this is going to be lost
as soon as you start going between two
different protocols.
So we're also going to have to deal
with routing loops or more importantly,
preventing them from happening.
So these are the things we're going
to be looking at in this skill.
So as you can hear, we have a lot of fun stuff to look at.
So let's jump in and get started.
I'll see you in the next video.