Routing
To
understand something in the networking world, you have to understand the
problem it’s trying to solve. Memorizing the configuration options for a
certain routing protocol won’t help you until you understand what it’s really
doing. This installment of Networking 101 is designed to be a gentle
introduction into the world of routing issues and concepts, arguably the most
interesting and important part of networking, explaining the problems routing
protocols address so you can understand why they do what they do.
Routing,
in essence, is the act of finding a path from one place to another on which a
packet can travel. To find this path, we need algorithms. They will generally
be distributed among many routers, allowing them to jointly share information.
Routing is said to contain three elements:
- Routing
protocols, the things that allow information to be gathered and
distributed
- Routing
algorithms, to determine paths
- Routing
databases to store information that the algorithm has discovered. The
routing database sometimes corresponds directly to routing table entries,
or simple words
Routing is the process of moving packets from one network to another networkRouting involves two basic activities:
- Determining best path
- Forward packets through these paths
There are 3 different types of routing
•Static Routing
•Default Routing
•Dynamic Routing
Static Routing
• It is configured by Administrator manually
•
Mandatory need of Destination Network ID
•
It is Secure & fast
•
Used for Small organizations with a network of
10-15 Routers
•
Administrative distance for Static Route is 0 and 1.
It is the “trustworthiness” of the routing
information. Lesser the Administrative distance, higher the preference.
Syntax:
Router(config)#ip route
<Destination Network ID> <Destination subnet mask> {<Next hop IP
address> or <Exit Interface type><No.>}
Dest
N/W ID:
Network ID (of remote network)
Dest
subnet mask: Subnet
mask (of remote network)
Next
hop ip address: IP
Address of the Next Router (directly connected)
Exit interface type & Number: outgoing
interface type and number
STATIC
ROUTING – Example 1
Configure Static Route to allow LAN of Chennai to
communicate with LAN of Hyderabad and vice-versa:
ON CHE :
CHE#configure terminal
CHE(config)#ip routing
CHE(config)#ip route
10.0.0.0 255.0.0.0 Serial 0
ON HYD :
HYD#configure terminal
HYD(config)#ip routing
HYD(config)#ip route
192.168.1.0 255.255.255.0 172.16.0.1
To verify, the following commands can be give on all
Routers
Show commands:
Router#show ip route
STATIC ROUTING – Example 2
ON CHE :
CHE#configure terminal
CHE(config)#ip routing
CHE(config)#ip route 10.0.0.0 255.0.0.0 172.16.0.2
CHE(config)#ip route 192.168.2.0 255.255.255.0
172.16.0.2
CHE(config)#ip route 172.17.0.0 255.255.0.0
172.16.0.2
ON HYD :
HYD#configure terminal
HYD(config)#ip routing
HYD(config)#ip route 192.168.1.0 255.255.255.0
172.16.0.1
HYD(config)#ip route 192.168.2.0 255.255.255.0
172.17.0.2
ON BAN:
BAN#configure terminal
BAN(config)#ip routing
BAN(config)#ip route 10.0.0.0 255.0.0.0 S1
BAN(config)#ip route 192.168.1.0 255.255.255.0 S1
BAN(config)#ip route 172.16.0.0 255.255.0.0 S1
To verify, the following commands can be give on all Routers
Show commands:
Router#show ip route
