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STATIC - DEFAULT ROUTING

5. Default Routing

Okay, now in this section we'll see how to configure the default routing and when and where it will exactly be used. Default Routing Now default routing is used in two scenarios, and the first scenario is for unknown destinations. So if you want to route any packet to any unknown nation like the Internet, we use default routing, and it can also be used at the end locations. So there are two scenarios where default routing is used. Let's go over these two scenarios in greater depth. So the first example is the first example, which, as I said, can be used for the Internet. If you want to route any packet to the Internet for any unknown destination, we use Jeep for routing. Let's try to understand how it's going to work. Let's take an example. I have three routers, and these three routers belong to my different branch offices. I'm using one eight-one section, one network, two dots, and three dot network.And all these three branch offices are able to communicate with each other based on the static routing, as we did in our previous scenarios. And everything is working fine. So if any package is between one and two, it will work. And also, any packet distance from one to three or three to two is going to work. So I already have the static route configurations. If you want, you can go and verify the router one.I can give a command called "Show IP Route" to verify. You can see I already have a static route, and everything is working fine as we did in the previous example. So now let's take an example. Is router three connecting to my ISP and then connecting to the internet from there, okay? So from there I'm able to access my Yahoo!, Google Gmail, or something like that on some Internet sites. Now. I'm on three. One. Now the user is sitting on three chairs here. So, 182-1631 here. Now this user is going to send a request, and it's going to send a request to @yahoo.com. It says he wants to access www.yahoo.com, and he's going to enter the URL path, and the source address will be 192.168.1.3 from where the packet is coming. That is from three one computer.And the destination is somewhere on the Internet. Here's the Yahoo server. Assume that the IP address of the Yahoo server is 2/1/1; this is some public IP on the Internet. And the answer is two, one, one. So, whenever a package arrives from 182network, you can find it here: 182 network. And the destination is on two networks, which means they are on different networks. So whenever a PC realises that it is on a different network, it is going to forward the packet to the gateway. So that means that it enters the router, and what the router is going to do is check the routing table, swipe your route, and it will see whether there is an entry for this destination in the routing table or not. If there is no entry, what it is going to do is simply drop the packet. So let's verify whether there is an entry for that particular network or not. So you can go to router three to see if I can show you the IP route if I go to router three. Router three has an entry from the 182-1681 dot network, two dot networks, and three dot networks, but there is no entry for the two dot network, which I discussed. So which means what happens? so let's verify if there is no entry. Anyway, here I don't have a real internet, but generally what happens is that if I try to ping from one of the PCs that is 182-1683 and I'm trying to pin to some address that is not present in my network, or if it simply comes from the gateway that is 18163 100 and that 3100 says that it doesn't have an entry, So it's going to simply drop the packets. So, in this scenario, I want to ensure that if any packet comes from three one, if it is Justin for Two or Two network, which is somewhere on the Yahoo here, I want this package to go to the router, and from the router, I want the packet to be forwarded to the ISP, and from the ISP, it should reach the Yahoo server and the replies should come back. But in this scenario that will not happen becausethere is no route in the routing table. So if you don't want to drop the packet, then we need to write a route. You must proceed to Router 3, and then we must create a route indicating that IP route destination network entry. We tried a static route. If any packet is just transferred from two to one, we need to tell that to send it to two two.Assume the IP address of this router on the ISP's two networks. I'm going to tell that send it to two two. So which means now if any package distance for Yahoo.Server which is 2211 will be send to the routerand the router is having an entry for that network,it will forward it to two two ISP. From there, it reaches the Internet, and it will communicate like that. But let's take an example. The other user in my network wants to access something called "some other website on the Internet," Google. com or some other website, and the IP address on that Google is, let's say, 51 one.Again, the same thing happens. The packet goes from three to two, and the destination network is the 50 network, so there is no route in the routing table. It's going to drop the packet. If you don't want to drop the packet, we need to add one more static route saying that if any package is coming from the 50 network, send it to two two two. But now the question is, how many static routes can you write? Because on the Internet, you have thousands upon thousands of networks, and it's not an easy job. It's not at all possible for you to write the static route for each and every network. Now in this kind of scenarios, what we needto do so because if the router do nothave an entry, it's going to drop the packet. And again, writing the static route foreach and every network is not possible. So what's the alternate solution for us? Now there is an alternate solution called default routing. Now what I can do is go to this router, which is currently written. I can write one default route and I cansay that IP route zero, the meaning of zerozero means it can be any destination. That's what it says. And then I can write zero zero,it can be any submit mass. So, that means in place of the destination network ID, I'm writing all zeros. And in the case of the destination subnetmask, I'm also writing all zeros. Simply send it to two (2). So I'm not writing this. I'm not writing these entries. Instead, I'm going to write a single default. Now, once you add this entry to your router, you'll see something called SS 2. As a result, we'll see this in greater detail in our lapse scenarios. But once you add this entry, now what happens is that if this user (182-1631) wants to go to two networks, one of which is on a different network, the packet goes to the router. Now the router is going to check the routing table. There are currently no entries for two or two. And instead of dropping, it's going to see the default route. Having said that, my administrator stated that if any route is destined for an unknown network, instead of dropping 72 two, which means it will reach the ISP, and the ISP knows better. Where is Yahoo? There is Google. So it will ensure that it reachesthe packet to that particular server. And then your reply will come back to the ISP router, which I see will reply back to your router, and then it will come back here. So that is how default routing is going to help us route your packets on the Internet. So remember one thing. Whenever any package comes on the router, if there is no destination entry in the routing table, it's going to drop the packet. So when you're adding a default route, we are saying that if you don't have an entry, don't drop it. Send it to this route; send it to the ISP. So, our job now the user sitting in myLAN or my router don't know where is Yahoo. But still, I will be able to communicate with Yahoo. Because my job is if I don't know where is Yahoo. Instead of dropping, I'm simply sending it to my ISP, and my ISP knows better where Yahoo is. And then that's how we can communicate with the different networks on the Internet. So remember one thing: Whenever you want to route any packet to the Internet, you must use default routing. So the default routing is the one that we use. We don't use static routes because adding the static route is not an easy job, and we don't even use dynamic routing between them. There is one option called BGP. It can be used, but there is something a little bit beyond the scope of your CCN exams. Okay, but mostly, we use default routing, so using default routing is mandatory. We need to use it if you want to route any packets on the Internet. So this is the first scenario where default routing is more applicable. So let's try to understand one more scenario where we can also use default shopping optionally, that is, the second scenario: end locations. we can use at the end locations. So let's take an example. I got to my head office. Let's say I've got some autos here: router A, router B, router C, and router D, and we'll give them some names. So I got these four routers connected, and then I got more routers like router E, and then I got router F, and then I got router G here. So as you know, this is how they are connected. Now, from the router E, I want to go to So, and for destination, we are going to write the wire path via which source or via which route. So from the router E, to reach A anywhere, you have to go via A, right? And from the router E, if you want to go to B-C-D-F like this, So from the router E, if you want to go to A, you should go this route. There's only one route, but from the router E I want to go to B, so I have to go via A only. After that, either I can go from here or I can go from there. That's the secondary thing. But you have to go only via A, and from the router A, I want to go to D; I should go via A only, and from the router E, I have to go to C; I have to go via A only. Either I can go from here, or I can go from here like this. Now, if you just try to reach all the destinations from here, there is only one common next stop. Even if I want to go to A or to D or to F, I have to go via A. So in my scenario, from the router, this is a common next hop to reach all the destinations. Okay? So one option is to write multiple static routes, or I can simply configure, go to this router, and write, or I can say IP route. I can say something like "zero, zero, zero, whatever the destination, what would be the submit mask?" And the next top address is A. So instead of writing multiple static routes here, what I'm going to do is write one single default route saying that wherever I want to go, I should go via A. So why do I need to write these many static routes? So if you write, there is no problem. It's going to accept it; it's going to work. But on the end locations, where you just have one common next stop—a very, very common next stop—and there's only one next stop, And to go to any destination, that's a common next step. So simply, we can write "default out." So this way, we can minimise the size of the routing table. Because we don't need to add this many entries. It's going to minimise manual configurations. Instead of writing static, we can use default routing. But you cannot use the default route again on the router. due to the router's three connections, three links And you cannot say "default route" or "zero" on all the sites. Okay? You can have two static loads and one default route. That is okay, but you cannot have all the default routes. Again, the default routes are more applicable if you have one common next stop to reach all the destinations. The same rule is going to apply here. The same rule is going to apply here as well. So, optionally, we can use defaults at these end locations. Okay, so more of this default routing, like implementing and verifying it, will be seen in our next video.

6. Verify Default Routing

Now in this section, we are going to continue with the default routing that we have discussed in the previous examples. If you remember from the previous video, we have seen that default routing can be used in two locations and in two scenarios. If you want to route any packets to the internet, or even if you want to route packets at the end points. Now in this lab, what you are going to do is assume that this is my end location, that the router one is my end location, and if you waited five minutes from the router one to reach 18216 2, similarly, if I want to go to the 18163 network, I have to go ten and two. And even if I want to go to the Eleven Network, I should go to VR 100 two.Now, if you notice the common next to it, it is the same. Now either I can write three static routes like we did in our previous example—remember, we can write three static routes—or I can write one single default route. Because anyway, wherever you want to go, you have to go in one common direction only, and this is the exit router, which has only one direction. So I can use my default router. So that's what I'm doing here. I'm going to use default routing on Router 1, and I'm going to do the same on Router 3. So why? Because here, even in the router three, also to reach18162 network, the common next stop is 110 one. And to reach 18160 one network, thecommon next stop is 110 zero one. So to reach all the destinations, the common next stop is one. Which means on routers one and three, instead of using three static routes, I'm going to use one default route. Okay? That's how we are going to verify. But on the router too, we are going to use static routing. Because to reach this network, you had to go YR tenone, and for the router to reach this network, you had to go YR 110-2 at the next stop. So that's the reason I'm going to use static routing in this scenario. Now, you can assume that these two are the end locations with a common next hop, and then the router that is in the middle, which has multiple destinations, uses static routing. So you can make assumptions either in those scenarios or in the real ones. Also, if you are routing any packets to the Internet, your router will most likely be connected to your ISP's router. And this is my ISP router here. And from our router, we always configure default routing. So you always say default route, and we always say zero, zero, zero, whatever the IP address of the router on the ISP and from the ISP router to our network. So ISPs will always confirm static routing. and that's true for the static routing. If I use the 182-1681 network in the country as my private network, you will not have a static route for the private network, but you will have a static route for the public network, whatever you are using. Because in real-world production networks, you will have a private IP address that is not recognised by ISPs. So generally, what we do is put a net on the traffic network. More translation on this network: We have a separate session for this, and we will translate this private IP with some public IP. Assume I'm translating with the IP address 51. And we are going to write a static load for the public IP, which means this is going to identify your network with this public IP on the internet. That is how it will be on the production network. But here, we are not using that. Here, we are not using any kind of network, and we are not using any public IP here. So we are just having a static connection from here to here because we are not connecting to a real Internet here either. But this is the typical real production network scenario. Now you can assume the same scenario like that. You can assume this is my ISP, and from the ISP we are going to configure a static route. We are going to compare the static route for the customer and assume that this is my customer's default route toward his ISP and another customer's default route toward his ISP. Now, we can assume that, but in the end, we're not using any real Internet or connecting any real Internet connections here, so we'll see how the default routes behave once we configure them. Now, on the router one, the prerequisite for this lab is that you need to have some IP addresses pre-configured in the lab, just like we did in our basic scenarios. And I don't have any of the routing here. I just have the basic IP addressing, and all the interfaces are up and running. So we're not going to use static routing in this scenario here.Instead of using static routing, we are going to use default routing or the end locations that are on routers one and three. Let's go to Router 1. We need to say "IP route" to configure defaults. Instead of writing a destination prefix, we just need to say 0040 and then the summer mask, also 40. It can be any submitted mask. And then we are going to write the next top IP address. So in my scenario, the next top idiot IP address will be now, once you add this statement. If you verify the routing table, you should see one entry added in your routing table here. That is a static default. You'll see something called an "S" asterisk. And then this represents that it can be any destination, and it can be any submit mask. Anything unknown packet will just simplysend it to ten Two. That's what it is going to say. Let's do the same thing with router number three. Because instead of using static routing on Router 3, I'm going to use default routing. So, as shown in the diagram on the left, IP Routes Destination Network ID The submit mark is the destination network ID. 110 001 is the next highest address. That's the next option. If I could show you the IP route, you'd see that S Astrikand is using 110 zero one to get anywhere. Now, on the router 2, we are going to configure a starting route on the router 2. Because we don't have a single route, we have multiple routes. So I'm going to verify the share IP route. And then on the router Two, I'm going to say IP route. If any package is distant from the one-eighth 21161 network (255-255-2550), the package should be sent to tenone, that is, router one from router two. To reach one network, the next top address is, and then if any packet is just in for one and two, I'm saying that it should. So, assuming this is my ISP router, you have a study route for the public IP address, whatever you're using; we don't have a study route for the private IP address. So I'm doing it here because we don't have a proper setup. You have a static route for the public IP, and this router will be doing that network address translation, which is translating your one-dot network to some $50 network, and you are studying out for the $50 network. So for more on this, we'll be getting into that in our NAT session separately. We'll come back to this kind of implementation in our next lapse as well. So let's verify now. So, from the standpoint of verification, the main point is that I should be able to access everything from a single network. I should be able to communicate with 180 to 162network, and also I should be able to communicate fromone network, three dot network, and also I should beable to communicate with One, Two and three network. So all the three lamps should be able to communicate with each other. So let's go to any one of the PCs. Here, on the first network to verify the IP address, we can use Ipconfig, and then I'm going to use 192.168.1.81, where I'm trying to ping from one and should see the reply. And even if I try to ping 1631, that is, from one network to a three-dot network, I should be able to ping. This router now claims that any packet is simply sent. I'll send it to router Two and tell the router to send it to router Three. And then, out of three, return it to the lamp interface. More like a normal routing, If you want, you can try Chris 181-6831. Your packet destined for three one will go to 100, which is router one, and then to router two, and finally to three one. So even if I try to trace some address that is not present in my network, if I try to trace your traffic, it will go to this one because the source address is one and the registration address is 172-16-1, which is on a different network, and the PC says you belong to a different network. Please go to the router, and the router says it doesn't know where to find the time to do 60 network, but at the same time it knows that I have a default route of zero. It's going to simply forward it to router two, which is your highest point, and this is a spirit router that is going to see the route normally in the production networks. Although your ISP is aware of the location of this public network, it will be dropped in this scenario because it is not your primary Internet connection. So that's how the default routing is going to work. And for verification, we can use a similar kind of topology with three routers, and we can practically verify this. So you had the same lapse? Similar lapses, the exact same IP addressing with the same configuration, and the exact show and trace commands, whatever I've used here, are also documented in the workbook in the same way.

7. Routing Lookup

Now in the previous two sections, we have seen how to configure the static routing for two routers and three routers, and we have practically verified that once you configure the routing, you'll see that one door network and two dot networks will communicate with each other. But I just want to understand how it's going to work, how the routing process is going to happen. So let's try to understand. In this section we are going to see how the routing is going to work, how the router is going to do the routing lookup, and what happens if there is no route in the routing table or something like that. So this is really important for you to understand because when you do some troubleshooting on the routers, this is how we do the checking, like whether there is an entry there or not? If there is no entry, then what are the thingswe need to check and what might be the reasonfor there is no communication between them like that. So the first thing I'm going to generate is a ping message. Let's say the source address is 192.168.1. and then 16213 one.Let's say I'm going to send a packet from161 one and the destination is 18163 one. So whenever a PC realises that the packet is here, it will see what the source address is. Source address is 182-1621 one andthe destination is 163 one. The first it will try to differentiate whetherthey are on the same network or whetherthey are on the different networks. Because of the submit mask, they are now logically in different networks; we are using two PowerPads and two Pi 5250. So there are three network portions, which means they are on different networks because the network portion is different. So whenever a PC realises that the destination is on a different subnet, it will simply forward the packet to the gateway, if you define what the gateway is. As a result, if you know who the gateway is, So how do I define the gateway on the PCs? If you remember, we go to configuration mode and then we just assign that gateway something like this. Would you like that? If I don't define this gateway, the PC will never know who the router is. Assume that if I remove this address, I will remove this address. If you remove this address, then the packet will never reach the router; it will only search within the land, which means any packet distributed for a different network will not be sent to the router, and if it is not sent to the router, there is no way it goes to the other networks. So if you want to have a communication process between two or more different UFO networks, every PC in the LAN must know who is the gateway. That's mandatory, and we define the gateway address by using an option called default gateway. So the default gateway option is required for all devices if there is no default gateway assigned or if the default gateway assigned is incorrect. In that case, your packet will not reach the wrong party. So this is the first thing we need to check: whether the gateway is correct or not. Okay, so the next thing is once thegateway is correct, once the gateway is assignedon, the packet reaches the router that isrouter one, the packet reaches router one. What router one is going to do? Router One is going to check the routing table. Now, how to verify the routing table? So first thing, what is the destination network ID? The packet reaches the router, and the destination network ID is 192 1683 network.So the routers are not concerned about the exact IP addresses. They work based on the network IDs. It says the packet is coming from a one-door network, and it is supposed to go to a three-door network. Okay, so let's go to RouterOne and check the routing table. So if you remember from the previous section, we did the routing, so it will see whether the router one has an entry for a three-door network or not. If there is an entry, it willtry to forward to ten two. If there is no entry in that caseit is going to simply drop the packet. The packet reaches the router, and it will drop here, and it says, I don't know where Stour Network is, so it's going to drop your packet." So when you're doing some troubleshooting, ensure that you have a route in the routing table. If you have the route in the routing table, it means the router knows where it is and also ensures that the next stop address is correct. Instead of giving 10 and 2, if you give some other address—11 and 2 or 15 something—and it is not going to reach this network in that case, it will affect the communication. So in this scenario, the next stop is correct. So the router says if you want to go to two networks and three networks, you have to go via ten and two. But now the router says okay, so I have to go through ten-two to reach the three-dot network, but where is this tendered network on which interface? So the router is going to check the routing table one more time, and it says to go to the 10 network. I have to exit zero by zero, it says okay, and exit this interface so that I can reach router two. Now your packet will exit s zero by zero, indicating that it is checking the routing table one more time, and it will exit s zero by zero before reaching Router Two. Now, again on Router Two, the same thing happens. It's going to check the destination entry. My destination network entry is the 192.168.3.1 network. And then on Router Two, it is going to check the routing table. Let's verify the same on the router. 218-2162. Three network. Do you have an entry here? We have an entry, which means the router knows where the 182–683 network is. And to reach that network, we have to go via 110 Two.So that's the next hall. Okay, so it says the router should say, "Okay, you want to go to this network; go via 110-2," but the router says, but the packet says okay to go to 110-2," so which interface, which direction should I go in? It sees this direction and says, "Okay, you want to go to 110 Two; go out of S One." Or actually, it will check the routing table. Let's go to Router Two and check one more time. Where is that Levendo Network? It is on S zero by One, which means thepacket simply reaches from the Router Two, reaches Router Three. So it goes out of Sq by one, and out of Szero by one, meaning the packet reaches Router Three. Router Three. Again, the destination address is 182-1683 network. The packet says, "I want to go to your network." And on Router Three, it's going to take the routing table again and show the IP route. And do you have any entries for three or four networks? Yes, we have an entry, and it is my own directly connected interface. On M zero by zero, the Router Three says, "Okay, to go to the Three Door Network, you have to go out of this interface, M zero by zero." From there, the packet reaches the switch, and the switch will find the exact device address, which is Three One, and then it will do some ARPresolution ARP to find the Mac address. This is something I'll be getting into more detail in my switching concepts. So as of now, I'm not getting into that. It reaches the switch, and the switch will take the responsibility of forwarding it to that particular host. Now, this is how the routing lookup happens. This is how the routing lookup happens. And even when you're doing some troubleshooting, we need to ensure that if you have some issues, like One is not able to communicate with Three, we know about it. And you need to check, hop by hop, whether the next hop is correct or not. If the interface is up or not, like that, your router's IP address will be the gateway. So when we say "gateway," it's nothing, but we are giving the IPS of the router facing the line interface. So understanding this routing lookup is really important for you. And this is something that's not specific to static routing. It can be any routing protocol. Whatever the routing you're using, it's going to do the same thing. The only difference is if you're using static routing, which you may see as S. If you're using dynamic routing, you may see R or D. Something like that depends upon the protocol, like Rip EHRP SPF. But understanding this basic routing process is really important to know how the router works and how the routing lookup happens, and then also for troubleshooting as well.

8. Building Routing Tables

In this video, we'll see what is the default step-by-step method of the routes getting installed in the routing table, what is the default order of selection, and what it is going to see initially. So now, by default, let's take an example. I'm going to router one, and then I'm configuring a static route and saying IProute, and I'm going to say 192, 168, and two dot network, and the next top address is this. Okay? So before the route gets installed, whatever kind of routing you're using, it doesn't matter. So for any route, before it gets installed in the routing table, it must have a valid next stop. It is now verifying the next stop. If the next stop is reachable, in that case, only the route will be installed in the routing table. So if the next stop is not reachable, in that case, it was not going to install the route in the routing table. So the mandatory condition for the route getting installed in the routing table is that you must have a valid next-hop address, and that next-hop has to be reachable. Now, assuming that the next Hob is reachable, In that case, let's say there are two possible routes from router one to the 192.168.1.1 network, and possibly two routing configurations. Now there are two possible routes here. Now, in this case, first it willbe going to see the longest match. Now, whichever route has the longest match, that route is more preferable, and it's going to take the longest match here. Let's take an example. In my scenario, let's say from this route that the destination network is 192, 168, 20, and the subnet mask is 24. And whereas the alternate route here is 192, 168, 2100, and the slash value is 27 or 28, let's say 200:27. Now, you are able to receive the same route here, but there is a different mask. In that case, it's going to prefer the longest match. So first it will see the longest match, so that this route will be installed in the routing table here. Now, in case if there's a timein the longest match, then the nextcondition, it will see the administrator distance. If the route is coming from rap and the static administrator distance is 120 and the static administrative distance is 1, it will install the routes based on the administrator distance. Or it could be two static routes that you've configured, as we did in the previous scenarios, routing static routes based on administrative distance. or one static route, or the default route is one and the other one is ten, it's going to install the least-administered distance. So before it actually verifies the administrator distance, it will see the longest prefix match. And if the prefix match is the same on both sides, then the next condition is going to be the administrative distance. And then if the administrative distance is the same, like if both routes are coming from Rap and Rip, in that case, whichever route has the least hop in Rip, like two hops or three hops, two is more preferable. It's going to install the route based on the metric. And let's say the metric is the same in that case. Finally, it is going to do something called load balancing. Now for basic verification, I've got a router here; on the router, if I verify showIP route static based on the same lapse as we did in the previous floating static routes, Now to reach one six one network, there is astatic route and that is going via ten two. Now what I'm going to do is I'm going to configureone more route static route for the same 192-1682 network. But this time I'm going to configure it as a 27-submitmask. And for the next operators, I'm going to give twelve zero two and also a distance of ten to the administrator. Here's what I'm doing: the Conservatives' two-dot network. This is 24, this route. And the other route which I'm converting is it istwo dot network, the same network, but it's slash 27. Let's verify which route will be installed in the routing table. So, if I go to router one and verify the routing table, as well as show IP route static, I can see that both routes are being installed in the routing table. I can see both the routes installed in the routing table. But it's going to be the longest match. This means that if it has a packet to send within this range of 27, it will send it via two. Let's say there is a trace. If I just try to trace it here to 192, 168, 227, it comes in the range of zero to 31. If I'm tracing to something like 221, it's going to be in this range, but if any package comes outside this range, outside this range means 27, so here it will be zero to 21. And anything outside this range—if I try to trace it from nine to 116 or 2100, it's something outside the range. So it's forwards based on this. So the first thing it will see is the longest prefix match. And if the prefix is the same, in that case it is going to consider the administrative as a deciding factor, like in the previous scenario. We discussed that we have configured some administrator distances for the static road. Here is one, and by this route, we have configured ten. It's going to install the route with the administrator-distance value of one because it is the same. But in case if both the administrative distance aresame, in that case it will see the metric. In the case of static routing, there's no metric. But if you're using rip protocol, In that case, it will see that from this route to reach here there are two hops, and from here it is just one hop. It will decide the best route based on the Hopkins in the case of Rap; in the case of EHRP or OSPA protocols, it will see which has the least cost. And if both the roots have the same metric, then in that case, it will install both the routes and forward the traffic via both the routes. And that is what we call as equal cost load balancing. Now, this is the default passion process or the default Stephanie process, which is considered by the routers when they install the route in the routing table.

9. Floating Static - Default Routing

In this video, we'll quickly review some of the basics of static and default routing initially, and then we'll go and verify some of the other options. Advanced options relating to starting and default wrapping That's what we call a floating static route, or the floating and default routes. And then we'll implement a small scenario, and then we'll verify the same on the command line. So let's get started with the basic routing here. Now, please return to the CCNA topics. Static routing is something manually configured by the administrator. The administrator has to go to the command line, and the administrator has to manually configure the route for each and every destination from router one to the three-door network, and from router one to the two-door network. And in order to do that, you must know the rest of the network ID. And if you don't know the rest of the network ID, you cannot write that out. Now, for each and every destination, it has to be done manually through configurations. And this is something: it's not applicable to the big-size networks. Now to configure the standing route, either we can write an IP route, a destination network ID, a destination subnetmask, and either we can write the next top IP address, like from the router, to reach this network, and then we can write the next top IP address that is the next stop. Or we can write our own exit interface. So on that option, our own exit interface here is zero by zero, or we can write ten or something like that. The main difference between these two is that if you add the next hop, the router will most likely check the routing table twice. Because, if there is a destination network, let's say router one wants to go to the 116-2 network. If you're adding the next stop in the routing table, you'll see this route as S. It's going to say that to reach that particular network, it has to go via 102, and then it is going to see the routing table one more time. The next step is to figure out which interface is on S zero by zero. The router will then forward back out of S one by one. Now, the routing look up generally happens twotimes if you write the next stop. Now, if you're generally writing the exit interface, let's say if I'm writing 192, 168, or a two-dot network, if I'm directly writing my exit interface, the routing generally happens only one time.So because the router will see this as a connected interface, and then it will simply send out a zero-by-zero interface automatically, let's get into the command line and verify the same. More on this, let's say I got a small defaulttopology pre configured here with the same three routers. Here I'll go to router one, and I got 192, 168, one network, two dot networks, and three networks exactly as per my topology. If I go to the command line of the router, So if I get show IP route I can seethe router one is already connecting to three interfaces thatis tend to network twelve network and 192-1681 network. This twelve dot network, ten network andthis is 192, 168, one dot network. If you want to write a static route, generally we do it with a command. Let's say I'm going to write IP route one nine, 2162 network 255-255-2550, and the next stop I'm going to write is 100 two. So let's go to router one and write the next stop as "ten two." Now, there's one way to write the static route. And there's an alternate way to reach the 192-1682 network. Alternatively, write down the three networks 255, 255, and 2550, as well as the next top. Now, there are two different ways. As I said, either we can write the next HOP interface or we can write our own X interface. Now, on the router, to reach this network, I have written this route. Now probably from the router wantto reach three door network. I'm going to use this route. And instead of writing the next hop, I'm writing my own exit interface. As a result, my own ex interface is zero by one. So I'm going to write to reach the three-door network. So I want to prefer that route. The direct route from the outer one to the auto route three And I'm writing like this. And then if you want to write onemore route, let's try for eleven non network. Despite the fact that the van connects the outer two and out of three, And then I'm using ten or twelve. So the major difference in the routing table is that if I show the IP route as static, you can see if I'm writing the next hop. Normally, it will have an administrative distance of one. And you will see them as a static route, with the next stop visible. Now, in this scenario, the router asks if it has anything to send to the todo network. It's going to see the next job. And then it will take one more time the routingtable, it will see what is that next top ison which interface and then forward out of zero interface. So the routing lookup generally happens two times if you are writing the next hop. However, if you're writing a directly guided interface, such as the exit interface in my scenario, I'm writing a zero by one to reach the three-dot network. I can see this as a static route. And then it says it is directly guided by this interface. Now "directly guided" means it may be directly guided to the next router or maybe more than that. It doesn't matter. Even though your destination is somewhere else, it still shows as directly connected. Now, in this kind of scenario, Mr. Distance will be zero. However, if you write the next stop, the administrative distance is one, and the routing lookup occurs twice if you give the next stop and once if you directly right the exit of. Now the major thing is when we need to use the next home. Now, there are some cases or some scenarios where it is not recommended to use Next Hop, especially if you have a network or if you're using a framework kind of implementation where you are implementing some point-to-point or point-to-multipoint connections where you have multiple next stops. So let's say the next top order is ten, 210, 310, four. Now, in this scenario, I'm using a zero-by-zero here, and in this scenario, it's always recommended to use Next Hop here. The main reason is that this is the point in a multiplexed network where you have multiple next stops. But if you use the exit interface now, the same interface is going to take you to three different directions or three different options. In this case, you must pay for the Nexttop interface, or if you're using broadcast networks to connect your locations to a broadcast network, a service for a network, we call these broadcast multi-access networks. In this kind of scenario, too, we use the next stop, which is something mandatory we need to define. But in the case of point-to-point links, let's say if you only have point-to-point links, we can probably define either the next top interface or the exit interface; it doesn't matter. But especially when you're using most of the point-to-multipoint links or the broadcast networks, we need to ensure that we are not using the exit interface addresses in this kind of scenario. So you need to manually define what the next-stop interface IP address is so that it will be sent only to that particular next-stop rather than sending it to any one of these.

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