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[AUDIO LOGO]

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Normally, in a
service provider core,

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we're going to be
wanting to run LDP

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on all of the same
interfaces that we're

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running our core
routing protocol on,

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such as OSPF or ISIS.

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Now some of our devices may have
a large number of interfaces.

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Going and configuring
LDP on all of those

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interfaces individually
when in fact, we really

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just want the same interfaces
running our routing protocol,

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and LDP can get a
little bit tedious.

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So we have this feature,
autoconfiguration,

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which allows us to turn this
on under the routing protocol,

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and then whatever
interfaces we enable

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for that routing protocol
will also be enabled for LDP.

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Now like most things that
happen automatically,

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this is generally
a good feature,

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but we do want to be
aware that you are losing

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a small amount of control here.

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If you did have
interfaces, you maybe

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didn't want to be running
LDP, in which case,

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maybe you still want to
configure that device manually.

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But let's go ahead
and jump in here

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and see how we configure
autoconfiguration

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on our devices.

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So there are two
ways that we can

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use to implement
LDP on our devices.

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The first is sort of the
more traditional way,

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which is manually configuring
all of the interfaces

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to run LDP.

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Now, depending on
our platform, that

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might be under the LDP
process, or that might

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be under the interface itself.

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But nonetheless, it's
still a manual process.

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Now this does have at
least one advantage,

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and that is that it does give us
precise administrative control

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over exactly which interfaces
are going to be running LDP.

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There is the possibility
that we don't necessarily

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want to run LDP on
all of the interfaces

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that are running our IGP.

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On a core device, I think
that would be pretty unusual,

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but it's certainly
a possibility,

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in which case manually
configuring this

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might be the way to go.

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On the other hand, that
can get quite tedious

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and even error-prone on
devices, particularly

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with a lot of interfaces.

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Again, human error can
come into play here.

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We miss an interface,
something like that.

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Now, one thing to add
to this a lot of devices

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do support interface
range commands,

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where we can configure multiple
interfaces at the same time.

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Some devices do.

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Some devices don't.

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It really depends on
what type of devices

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you have in your core whether
you can use interface range

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commands.

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But that could be a way
that we could configure

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multiple interfaces
manually, configuring them

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all at the same time.

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But for most environments,
a better choice

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would be to do
autoconfiguration.

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Now once again, like
a lot of the features

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we've looked at through
this entire section,

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this is supported
only by OSPF and ISIS.

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And that's generally fine
because those are generally

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the only two
protocols that we want

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to use under MPLS as
our underlay protocol

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since they're the only ones
that support things like traffic

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engineering.

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Now the advantage of
the autoconfiguration

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is, of course, it
automatically enables

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LDP on the interfaces that
are running the protocol.

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So once we configure
routing protocol,

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we're configuring LDP
right along with it.

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And the other cool thing
is this is actually really,

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really easy to enable.

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So we enable it under
the routing process,

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and all we have to do
on both iOS XR and XE,

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we simply say, mpls
ldp auto-config.

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Now in OSPF specifically,
if you want,

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you can specify an
area by simply adding

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area_id to the end of
this same command here.

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So if, for some
reason, you only want

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to run LDP in a
particular area, that's

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also an option with
autoconfiguration.

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In this video, we
took a look at a way

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to automate enabling
LDP on our interfaces

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right along with our
routing protocol.

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This, of course, is
called autoconfiguration,

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as we just saw.

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And it's only supported with
OSPF and ISIS, which, again,

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is generally fine because those
are usually the only routing

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protocols that we want
in the underlay anyway.

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Keep in mind, though,
if you do need

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more administrative
control than this,

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you can always just revert
to doing it manually.

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So that covers
everything that we

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need to discuss in this skill.

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That leaves us only with a
review in the form of a quiz.

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And that's exactly what
we're going to do next.

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Until then, I hope this has
been informative for you,

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and I'd like to thank
you for viewing.

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