ROUTING FUNDAMENTALS

ROUTING FUNDAMENTALS

Routing is a process of finding best route for sending data from one network to another network. 

Types of routing

There are 3 types of routing, they are:

1. Static routing 

2. Dynamic routing

3. Default routing

STATIC ROUTING

In static routing, network administrator manually feeds routing information in the routing table.

Advantages of static routing

Static routing is secure because only network administrator can add or remove network (s). It also reduces processing load of router therefore low configuration router can provide better performance. 

Disadvantages of static routing

It is not possible to maintain routing table in large network therefore it is recommended for only small network.

To show routing table

Router> enable

Router# show ip route

To add networks in the routing table (static routing)

Router> enable

Router# config t

Router(config)# ip route remote network subnet mask next hop IP

Let's look an example

In this topology,

For Router 1                            For Router 1                             For Router 1

connected networks               connected networks               connected networks

10.0.0.0 255.0.0.0                   40.0.0.0 255.0.0.0                    50.0.0.0 255.0.0.0

40.0.0.0 255.0.0.0                   50.0.0.0 255.0.0.0                    30.0.0.0 255.0.0.0

remote networks                    20.0.0.0 255.0.0.0                    remote networks

20.0.0.0 255.0.0.0                   remote networks                     10.0.0.0 255.0.0.0

30.0.0.0 255.0.0.0                   10.0.0.0 255.0.0.0                    20.0.0.0 255.0.0.0

50.0.0.0 255.0.0.0                   30.0.0.0 255.0.0.0                    40.0.0.0 255.0.0.0

Now we need to add remote networks

command syntax: ip route RemoteNetworkID  Subnetmask  NextHopIP


For Router 1

Router1> enable

Router1# config t

Router1(config)# ip route 20.0.0.0 255.0.0.0 40.0.0.2

Router1(config)# ip route 30.0.0.0 255.0.0.0 40.0.0.2

Router1(config)# ip route 50.0.0.0 255.0.0.0 40.0.0.2

Router1(config)# end

Router1# sh ip route

Router1# write

For router2

Router2> enable

Router2# config t

Router2(config)# ip route 10.0.0.0 255.0.0.0 40.0.0.1

Router2(config)# end

Router2# sh ip route

Router2# write

Router2> enable

Router2# config t

Router2(config)# ip route 30.0.0.0 255.0.0.0 50.0.0.2

Router2(config)# end

Router2# sh ip route

Router2# write

Router3> enable

Router3# config t

Router3(config)# ip route 10.0.0.0 255.0.0.0 50.0.0.1

Router3(config)# ip route 20.0.0.0 255.0.0.0 50.0.0.1

Router3(config)# ip route 40.0.0.0 255.0.0.0 50.0.0.1

Router3(config)# end

Router3# sh ip route

Router3# write

POINTS TO BE REMEMBER

Routing is a process of finding best route for sending data from one network to another network.
Static routing: In static routing, network administrator manually enters route information in the routing table.
Advantages of static routing: Static routing is secure as compared to dynamic routing because only network administrator can add or remove networks. It also reduces processing load of router therefore a router having low configuration can provide better performance.
Disadvantage of static routing: It is not possible to maintain routing table in large network therefore it is recommended in small network.
Command for Static routing is ip route
Administrative Distance (AD) value for static routing is 1