WEBVTT

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 Hello and welcome to this video, which
 is a refresher on the concept and

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 configuration of static
 routing for IPv4.

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 Just as a review, static routing is
 typically used in a small network.

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 It's when you really want to keep track
 of no more than about three or

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 four prefixes, because static routes
 are definitely not scalable.

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 They have no way of tracking if a remote
 network has gone down or come

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 back up. It's really only used for very
 small cases or for default routes

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 sometimes. No dynamic failover, but they
 are preferred over dynamic routing

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 because of their administrative
 distance.

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 Static routes only have a default
 administrative distance of one.

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 The only thing that beats
 that is a connected route.

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 A couple of different ways we
 can implement static routing.

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 They all start out the exact same
 way with the exact same command.

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 At the global configuration level,
 as we can see right here, you type

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 IP route. You type your destination
 like 10.10.0.

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 You type your subnet mask
 immediately after that.

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 This is all in the same line.

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 It just wrapped in the PowerPoint
 slide, but you get the idea.

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 That's the exact same
 in both scenarios.

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 The only thing that's different is
 that with a static route, you have

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 an option of specifying an IP address
 of the next top router you need

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 to send these packets to or
 your outgoing interface.

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 99.99% of the time, it's preferable
 and better to use the next hop.

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 So we could say 1.1.1.1.

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 So this would say, hey, 1111
 is directly connected to me.

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 And if I need to send any packets with
 a destination of 10.10.10, forward

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 them to 1111. The only time an outgoing
 interface would be appropriate

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 is that the actual outgoing interface
 is a point-to-point interface, meaning

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 it is not Ethernet or any
 flavor of Ethernet.

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 So for example, if your outgoing interface
 is using the PPP encapsulation

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 or HDLC encapsulation, those would
 be the only times you would want to

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 use an outgoing interface.

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 For example, IP route 1010, 255, 255,
 250, serial, zero slash zero.

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 Because I know that serial slash
 zero is using PPP or HDLC.

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 But like I said, most of the time, people
 are going to select an actual

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 IP address as their next top.

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 Now, a floating static route is the
 exact same thing as a regular static

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 route. The only difference is that you
 have artificially inflated or increased

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 the administrative distance to make
 your static route less preferable

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 than a dynamic route.

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 The idea here is that, hey, I have
 learned of something, some network

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 via a dynamic routing protocol
 like RIP or OSPF or EIGRP.

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 And I want to use that.

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 I want that to be my
 preferred route.

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 But if that dynamic route goes away,
 I do want to have a backup and I

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 want my backup to
 be a static route.

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 This is where you would have
 a floating static route.

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 Now, you can figure it exactly the
 same way as a normal static route.

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 The only difference is you artificially
 increased the administrative distance

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 value. So let me ask
 you this question.

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 Let's say in my routing table,
 it looked like this.

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 I have an OSPF route to the 4.4.0 network
 slash 24 via my neighbor at

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 2.2.2. He sent this to me.

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 Now, I have another neighbor who
 is, let's say, 7, 7, 7, 7.

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 I'm directly connected to him.

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 And I want to create a static
 route as a backup to this.

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 So I say, OK, here's
 what I'm going to do.

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 I'm going to go into global
 configuration level.

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 I'm going to say IP route to that exact
 same network with the exact same

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 mask going to connect
 a neighbor of 7, 7, 7.

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 Now if I just left that, if I just hit
 enter right now, that static route

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 would take priority over the OSPF route
 because a static route has an

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 administrative distance of 1,
 which is much lower than OSPF.

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 So before I hit enter, I need to put a
 new value of administrative distance

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 right here in order to make
 it less preferable to OSPF.

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 What administrative distance value
 do I need to select to make that a

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 floating static route?

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 Well, hopefully you said Keith.

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 OSPF has an admin distance
 equal to 110.

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 So as long as I make this floating
 static route, something bigger than

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 that, like 111, now it will
 be less preferable to OSPF.

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 It will not override
 my OSPF route.

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 That's the idea and that's the configuration
 of a floating static route.

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 And then lastly, a very common use case
 of static routes are for default

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 routes. So default route in your routing
 table would look something like

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 this. 0.0.0.0.0.0.0.0.0.

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 And then you'd have some
 sort of next hop.

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 So the way a default route works, this
 is like the least specific route.

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 You may recall from a previous video
 that I said that, hey, if a packet

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 comes into a router and we look at the
 destination IP address and we go

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 into the routing table, if we find two
 or more entries of different links

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 like, hey, that entry right there would
 match and the first eight bits

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 match my destination.

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 Oh, here's another entry over here where
 the first 24 bits match my destination.

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 Well, the most specific
 match wins.

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 This is just the opposite.

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 This is slash zero.

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 This is like the least specific
 you could ever get.

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 So here we would say, all right, anything
 matches this slash zeros means

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 you don't have to match any of
 the bits in the destination.

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 Just use this as like a backup,
 a default, a default route.

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 So if I have anything that's more specific
 than this, this default route

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 will not be used.

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 So this is a catch all.

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 This is like in order to prevent dropping
 packets where we don't know

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 where they're going to go, we'll just
 forward them out this default path.

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 So configuring that as far as the static
 route is concerned is exactly

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 the same. The only difference is the
 network is all zeros and the subnet

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 mass that goes along with
 it is also all zeros.

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 That is what qualifies
 as a default route.

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 And like I said, normally you would
 specify the IP address of a next hop

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 along with that.

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 And the way we verify these is just
 by looking in the routing table.

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 Typically with show IP route or show
 IP route static is how you would

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 verify for the presence
 of static routes.

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 So that concludes this video on a refresher
 of static routes, default

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 routes, and floating
 static routes.

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 I hope you found this
 video informative.