Static Routing

Static Routing

Static routing occurs when you manually add routes in each router’s routing table.  Static routing has the following benefits:

No CPU overhead

No bandwidth usage between routers

Only Administrator can choose allowed network

Static routing has the following disadvantages:

Administrator must really understand the internetwork and how each router is connected

in order to configure routes correctly.

Administrator has to add a route to it on all Routers manually.

Not feasible in large networks because maintaining it would be a full-time job in itself

Command Syntax

ip route [destination_network] [mask] [next-hop_address or exitinterface]

[administrative_distance] [permanent]

IP route:-  The command used to create the static route.

Destination network: - The network you’re placing in the routing table.

Mask: - The subnet mask being used on the network.

Next-hop address:-The address of the next-hop router that will receive the packet and forward

it to the remote network.

Exit interface: - You can use it in place of the next-hop address if you want, but it’s got

to be on a point-to-point link, such as a WAN. This command won’t work on a LAN such

as Ethernet.

Administrative distance :-  By default, static routes have an administrative distance of 1 (or

even 0 if you use an exit interface instead of a next-hop address). You can change the default

value by adding an administrative weight at the end of the command.

Permanent  :-If the interface is shut down, or the router can’t communicate to the next-hop

router, the route will automatically be discarded from the routing table. Choosing the permanent

option keeps the entry in the routing table no matter what happens.

Example:-

Router(config)#ip route 172.16.3.0 255.255.255.0 192.168.2.4

 The ip route command tells us simply that it is a static route.

 172.16.3.0 is the remote network we want to send packets to.

 255.255.255.0 is the mask of the remote network.

 192.168.2.4 is the next hop, or router, we will send packets to.

Default Routing

We use default routing to send packets with a remote destination network not in the routing

table to the next-hop router. You can only use default routing on stub networks those with

only one exit path out of the network.

To configure a default route, you use wildcards in the network address and mask locations

of a static route.

In this topology we are going to configure Default Routing on R1

To configure default routing on R1 command is :- 

R1(config)#ip route 0.0.0.0 0.0.0.0 10.1.1.2

To check routing table command is 

R1#show ip route