Routing Techniques, Static vs. Dynamic Routing, Routing Table For Classful Address

Routing

Routing is the process that a router uses to forward packets toward the destination network. The router makes the decision based upon the destination IP address of a packet.To make the correct decisionS router must learn how to reach remote networks. The routing algorithm is the part of the network layer software responsible for deciding which output line an incoming packet should be transmitted on. There is two technique of routing :

Static Routing

In this technique router is configured manually. The choice of the route to use to get from I to J (for all I and is computed in advance, offline and downloaded to the router when the network is booked. The manual maintenance of the routing table for the large network could require a lot of administrative time. Sometimes static router is used for the backup purpose.

Dynamic Routing

Dynamic routing makes it possible to avoid the configuration of the static routes. The router decision changes to reflect changes in the topology and usually the traffic as well. Adaptive algorithms differ in where they get their information (e.g. locally, from adjacent routers, or from all routers).

Routing table for classful address

IPV4 contain the 32-bit number to represent the internet address. This 32-bit number has the different format for different classes. There are 5 classes i.e. A, B, C, D, E. There were three address classes to choose from: A,B, C corresponding to 8-bit, 16-bit, or 24-bit prefixes. No other prefix lengths were allowed, and there was no concept of nesting a group of 24-bit prefixes, for example, within a 16-bit prefix.

References:

1. A.S. Tanenbaum, “Computer Networks”, 3rd Edition, Prentice Hall India, 1997.
2. W. Stallings, “Data and Computer Communication”, Macmillan Press, 1989.
3. Kurose Ross, “Computer Networking: A top-down approach”, 2nd Edition, Pearson Education
4. Larry L. Peterson, Bruce S. Davie, “Computer Networks: A Systems Approach”, 3rd Edition, Morgan Kaufmann Publishers