Single-Area OSPF Implementation

OSPF is defined as the Open Shortest Path First and it is a protocol of link-state routing. The link is the interface in the router. The link is the interface and description of that one and to the neighbouring routers. The interface of the description mainly includes in the IP addresses consider as an example of the interface, the various types of network which are in connection, the subnet mask, and different types of routers which are connected and this goes on. And this part of connection of all those links form a database of link-state.

In these the router sends the data or the signals in a state periodically of every thirty minutes the packets are (LSA) link-state advertisement and then the router state changes. In the OSPF LSAs they includes the information about the attached interfaces, metrics used and sort of variables. In the case of OSPF they uses the accumulate link-state information, and to calculate the shortest path for the each node they uses the (SPF) shortest path first algorithm.

In the topological database which was in link-state is required for the overall picture for the connection in the routers. The collection of the LSAs are received from the all routers which are in the same area are contained in the topological database. Because the data which was same in shared network for the routers and they have the identical databases. 

And within the hierarchy the OSPF is operating. In this the largest entity around the hierarchy is the autonomous system, which was in a collection of the network which have the common administrator and shares a common routing strategy. And the autonomous are divide in the various different areas which are attached in hosts and are contiguous networks which are in groups the following shows the sample example of the hierarchy of the OSPF 

Two primary elements are used in the Two-layer network hierarchy of the OSPF.

• Area: Contiguous networks of a grouping are the area. In the autonomous system the areas are the logical subdivisions.

• Autonomous system: collection of the networks in the system under a certain common administration and sharing a common routing type of strategy. An autonomous system logically subdivided into several areas and on sometimes it is also called as a domain.

A contiguous backbone area to be defined for the each and every autonomous system. All the other sort of area which are non-backbone are connected off to the backbone area. All the communication was done through this the transition area is the backbone area. In the open shortest path first the areas of nonbackbone are an additionally configured as the totally stubby areas, as stub areas, or the (NSSA) not-so-stubby areas to help in reduce the routing table size and the link-state database.