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Next, we'll look at some more
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with changing the administrative distance.
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And then, what happens in situations where
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is not a good indication of whether we actually
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So, we'll see, this happens in designs where
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there is a disconnect between the Layer 2 link status
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and the actual reachability over the segment.
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What's just common nowadays and things
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Or things like PPP over Ethernet for DSL.
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And also, if we are using...
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like multipoint frame relay or
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Now, with the static routes,
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as we talked about before,
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by default, they will all have an
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Regardless of whether we're pointing
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or we're pointing it at the interface.
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So, I mentioned some of the documentation says
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that is not correct.
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The interface itself is a distance of zero,
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but a static route is always
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Now, we can quickly see this in the command
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and...
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let's look at the Show IP Route Connected.
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If I were to say, IP Route 0.0.0.0
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0.0.0.0. So, a default route.
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And I point this out my
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but then, also point unequal longest match
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towards a next hop that is
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So, I'm routing towards the connected link,
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If we look at the Show IP Route Static,
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note that both of these entries are installed.
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If both entries are installed in the routing table,
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it implies that there's an equal
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So, they both equally match zero,
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and they both have an
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What's confusing is that the route
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it doesn't show in the table
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but we can see, that is the case,
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because otherwise, both of
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Now, for the floating static
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it's simply that when we define
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we can choose what is the preference of
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In this case, it says,
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in static routing, there's basically no
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because there's only one option."
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Now again, when you're looking at the equal
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we are looking at the administrative distance.
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When we are looking at equal longest
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then, we are looking at the metric.
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So in the case of a static route,
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if we are comparing static routing to OSPF,
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then, we're looking at the distance.
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When we're comparing two
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we're looking at the metric value,
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but configuration-wise, the metric
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So, they're not two separate
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Now, what this essentially
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say that "For this route, that
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I'll have a distance of two."
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So, anything that is larger than one.
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It means that when we
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if we Show...
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Show IP Route Static,
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the entry that is pointing to
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is the one that is installed, because this has
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if we look at the configuration here,
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IP Route.
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The first entry, since the distance
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it means that it's using
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The second route has a distance of 2.
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We're manually specifying it.
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Which essentially means, this entry would
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if the interface serial 0/1/0 was
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So, when we look to see,
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will we actually install a particular
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we need to know, can we do the route
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In this case, the route recursion
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So, if we say, Show IP Route Connected,
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and serial 0/1/0 appears,
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which it does.
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It means that the static route
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Now, if we look at the actual result of this,
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let's say that on...
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router 5,
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we have one route pointing towards...
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4's interface with the distance of 1.
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And the second route pointing over
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As long as serial 0/1/0 is up,
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we're gonna route packets that direction.
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We could see this if we
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and do a traceroute towards
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we see, this goes over
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If this link were down,
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let's say we go to router 4.
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And shut this interface down.
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0:06:47
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Since this is a point-to-point link,
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so, back to back serial link
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The lying protocol on one side
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is always an indication on what the
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So, if router 4's lying protocol is up,
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If 4's lying protocol is down, it means
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Since now, when we look at
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we cannot perform route
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0:07:18
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it then in turn means that any routes
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can no longer be installed in the table.
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0:07:27
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So now, our floating static route
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is installed in the place of the primary one.
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0:07:35
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If we look at the result of the traceroute,
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we could see now, we're forwarding
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where router 4 has the 0.4 address
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as opposed to the point-to-point
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0:07:52
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So, at this point in our studies, it's really
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0:07:58
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But the thing is, you don't
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from your possible configuration options
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So, do not assume that
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unless there's somewhere in the lab exam that
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0:08:17
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If they don't say anything about it, then,
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0:08:20
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in order to get the solution working.
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0:08:24
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And it may be as simple
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or doing policy routing,
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0:08:32
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Most of the time, you would see...
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that these type of solutions
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0:08:38
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Simply because there's too many things you can
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0:08:43
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So, I could put 50 static
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then, it would remove the need for me to do OSPF,
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0:08:54
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But you do wanna make sure that you...
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0:08:56
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you understand the details
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0:09:02
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So, you could potentially use it.
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0:09:05
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So again, let's look at out
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0:09:11
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It doesn't matter whether we're pointing
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0:09:15
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It says that, "Since these are
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if route recursion can be
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0:09:26
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the one with the lower
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0:09:30
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If the one with the lower distance cannot
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which would mean that
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then, the second one would be installed,
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0:09:42
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Now, once the interface comes back,
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if we say No Shutdown in this,
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we'll see that the
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to the primary interface,
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|
0:09:58
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which means that now, the traffic is routed
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|
0:10:05
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So, what's nice about this is that
|
|
0:10:10
|
is directly related to the
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So, as quickly as the router can detect
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|
0:10:19
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that's where the route is either going to be
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|
0:10:26
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Whereas with something
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|
0:10:29
|
normally, we would have to wait
|
|
0:10:33
|
before we can start our recalculations.
|
|
0:10:36
|
But in the case of point-to-point
|
|
0:10:40
|
it implies that ay route that pointed towards that
|