Why Use Static Routing? Static routing provides some advantages over dynamic routing, including: ▫ Static routes are not advertised over the network, resulting. static routes on nexus for nx-os , including (1), (2) and (3). STATIC ROUTING. This chapter addresses the end-to-end delivery service of IP and explains how IP routers and hosts handle IP datagrams. The first section.
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Static Routing. CCNA Chapter 2. Note for Instructors. • These presentations are the result of a collaboration among the instructors at St. Clair College in. Advanced Static Routes Parameters. The Administrative Distance of a static route can be changed to form a floating static route, which will only be used if there. Complete the modeling bestthing.info and be prepared to justify your answers to the A network administrator can manually configure a static route to reach a.
When you manually add routes to the routing table, it is called static routing.
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There are advantages and disadvantages in using static routing. The advantages are:. As you can see, the command is pretty simple. You need to specify the destination network address, its mask and the address of the next hop towards the destination.
You can also specify the exit interface instead of the next hop address.
Using the exit interface will cause the router to reply or ARP query and response from the next hop router and is not generally recommended. Let us configure our example network shown in Figure Figure is repeated as Figure so that you it is easier to understand , using static routing.
To configure static routing, you need to look at the path traffic will taken from source to destination and back from destination to source. Each router in the path should know the source and destination network.
So assuming our source is in network To view the routing table and verifying static routing, you can use the show ip route command. The output from all three routers in our example is given below:. Router1 sh ip route Codes: Though the output of the show ip route command will be discussed in detail later in the chapter and in the next chapter, here are a few things you need to know now:.
The outputs show that all the routes that you added above have taken effect and traffic can flow between the You may have noticed that Router1 still does not know about the network between Router2 and Router3 Though it is not necessary for them to know about these networks, from a troubleshooting perspective it better to add routes for these networks also as shown below:.
After these routes are added, the example network has complete reachability using static routing. Default routing can be considered a special type of static routing.
Configure Static Routing Protocal in Cisco Packet Tracer
The difference between a normal static route and a default route is that a default route is used to send packets destined to any unknown destination to a single next hop address. To understand how this works, consider Router1 from our example Figure , without any static routes in it. When it receives a packet destined to If a default route is added in Router1 with next hop address of Router2, all packets destined to any unknown destination, such as Default routes are useful when dealing with a network with a single exit point.
It is also useful when a bulk of destination networks have to be routed to a single next-hop device. When adding a default route, you should ensure that the next-hop device can route the packet further, or else the next hop device will drop the packet.
Another point to remember is that when a more specific route to a destination exists in the routing table, the router will use that route and not the default route. The only time the router will use the default route is when a specific route does not exist. The command to add a default route is same as that of adding a static route, but with the network address and mask set to 0.
In our example network, the only exit point for the Hence, we can remove the static routes from Router1 and Router3 and add default routes as shown below:.
Router1 config no ip route Router3 config no ip route Remember that since Router2 has multiple exists, you cannot use default routing there. It still needs the static routes.
In the above output notice that the static route to 0. Apart from that, the gateway of last resort is now the next-hop as specified in the default route. A second way of adding a default route would be to specify the exit interface instead of the next-hop address.
For example, on Router1, you can use the following command instead of the one used above:. While this will accomplish the same thing, the big difference is that a static route with an exit interface specified will take preference over a static route with next-hop specified.
This is because the administrative distance of a route with exit interface is lower than the other one. Administrative distance is covered later in the chapter. A third way of defining a default route is using the ip default-network command. Using this command you can tell the router to use the next-hop address of a known network as the gateway of last resort.
Scalability and Resiliency of Static Routing
For example, on Router1, you can use the following two commands to set the gateway of last resort:. The second command will cause the router to lookup the route to The difference between using the ip route command and the ip default-network command for adding a default route is that the route added using ip route command is local and does not get propagated through a routing protocol, if one is enabled.
The route added through the ip default-network command will get propagated by a routing protocol. Another thing to remember is that prior to IOS version You will remember from Chapter 2, that if the ip classless command is not used, the router will do classful routing and expect a default mask on each interface. For example If router R1 is connected to network So it then passes it off to R3 which has the If you have static routes pointing in one direction does that necessarily mean that IP communication will be successful?
What if the router R3 has no route back to This means that traffic from So with that being the case any PC on the Commonly static routes are used for floating routes as discussed in lab and a default route which is discussed in lab however, many engineers rely on static routes in their infrastructure due to a lack of understanding of dynamic routing protocols such as RIP, EIGRP and OSPF.
In this lab you will configure static routing for three routers that simulate a small business with locations in NYC, Miami and San Francisco each having separate IP subnets attached.
One thing that has yet to be discussed on the Free CCNA Workbook is the comprehension of physical verses logical topologies. Shown below is a logical topology of the network you will be building in this lab.
Check out the overall lab topology to view the physical topology. In this lab the Loopback0 interface on R1, R2 and R3 will simulate their connected networks which you will be configuring static routing for.
In this lab you will familiarize yourself with following new command s ; Command ip route n. The syntax of this command is ip route network subnet nexthop; so an example would be ip route Establish a console session with devices R1, R2 and R3 than configure the devices respected hostname s.
Initial Configurations! Create a Static Route on R2 that states to get to RTA config ip route Let's say we have a router with 2 interfaces and both interfaces have a path to a remote network.
The output from all three routers in our example is given below:. While this will accomplish the same thing, the big difference is that a static route with an exit interface specified will take preference over a static route with next-hop specified.