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[MUSIC PLAYING]

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So when we were
designing this network,

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we said right from the
beginning that router 1 would

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have to be a route
reflector, but that we

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wanted to see the problem that
it created before we actually

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turned it on.

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Well, in the last video,
we just saw the problem

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that it creates.

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The other routers
in AS 65001 are not

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getting the prefix that's being
injected into BGP on router 4.

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So now that we've
seen the problem,

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let's go ahead and configure
router 1 as our route

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reflector.

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So here on router 1,
if we do a show IP bgp,

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remember that this router
is getting the prefix

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from router 4.

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This, of course, indicates
that router 4 is injecting it

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properly, and it's getting to
its IP bgp neighbor router 1.

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It's just router 1 can't send
it to its other IP bgp neighbors

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in the AS because it's
not a route reflector.

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So let's go ahead and configure
router 1 as a route reflector.

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This is a very
easy configuration.

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We already have most
of the structure here.

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We just, of course, have
to go back into BGP.

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We'll go back into our
neighbor group, iBGP_PEERS,

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into the address family,
and all we have to do

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is route reflector client.

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We'll commit the change,
and exit configuration.

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Do note here that the
neighbors did bounce.

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And this is normal when
configuring a route reflector.

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So we want to make
sure we do this

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either hopefully
during initial design

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and setup of our environment or
at least during a maintenance

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window if we're
turning it on later.

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So now, let's go verify that the
prefix is showing up on routers

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2, 3, and 5 as it should.

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We do a show IP bgp.

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We see that it now has
the prefix from router 4,

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router 3 has the prefix from
4, and router 5 has it as well.

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So route reflector
is working properly.

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Let's do a little bit
more verification,

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let's go back to router
1, let's do a show bgp

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neighbor 10.2.2.2, and notice
here on the second page,

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under address family
IPv6 four unicast,

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it lists it as a route
reflector client.

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So we know that
router 2 is a client.

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Of course, we know that all the
neighbors are at this point.

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But you can see this in the
output of the neighborship.

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Also, if we do a show IP
bgp for the 100.4.4.0,

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also notice that it says
here that it was received

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from a route reflector client.

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And if we go to a device
that this prefix has

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been reflected to, so let's
just use, for example, router 5.

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And what we see here is
this reflected prefix now

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has route reflector attributes
on it, the originator

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ID, and the cluster list.

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Both of these attributes are BGP
route reflector loop prevention

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mechanisms.

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The originator is so
if this update were

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to get back, in this
case, to router 4,

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router 4 would be
able to look at this

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and say, wait a
minute, no, no, no.

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I originated this,
this is a loop,

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I'm going to
discard this update.

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The cluster ID is there to
prevent criss cross update

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paths if we have redundant
route reflectors.

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The main idea with that is
if we have redundant route

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reflectors, we're going to
set the cluster ID the same.

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We'll be exploring
that in the next video.

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Now, of course, if we look at
this prefix on router 4 itself,

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which is originating
the prefix, this

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does not have any
of those attributes

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because this is the
originating router.

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It hasn't been reflected.

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These also get removed
as soon as we send this

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to an eBGP_PEER, including
between confederations.

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Let's go look at router 7.

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Notice here, it has confed
external and confed internal

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on the two different paths,
but what we don't have are

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route reflector attributes.

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So in this video,
we looked at how

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to configure a route reflector,
which is the easy part.

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More importantly, we looked at
the route reflector attributes,

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how they get carried in the BGP
updates, where they are sent

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and where they
aren't sent, meaning

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they're not sent to
BGP neighbors or BGP

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neighborships even between
confederation peers.

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So now we really
only have one problem

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left in our
environment, and that

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is that router 1 is a
significant single point

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of failure.

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If router 1 goes down,
65.0.0.1 is pretty much not

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going to be able to
forward anything.

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So next, we're going to set up
a redundant route reflector.

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We'll do that in the next video.

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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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