What is the use of OSPF single area and multiple area ?ccna

This topic can go on and on, but i will mention one of the advantages of multi area over single area.

Basically in multuple area OSPF networks, if router does link stat changes, it will only affect that area routers. However, in single area network, all the routers will get affected if the link stat changes, which could result in below par performance of routers.

Its all about area is keeping your routing table organized and compact with the summary route. Area's can be represented as different geographical locations and area Zero will be the backbone so that ll areas need to be directly connected to area Zero. If somehow if your location is far away from area Zero and if you are not able to connect to area Zero directly then you can use something called "virtual links" to connect to the area Zero.

The Advantages of OSPF multiple areas are

 

Reduced frequency of SPF calculations.

Smaller routing tables

Reduced LSU overhead

The main advantages of multiple area OSPF is route summarisation between OSPF areas if each area is subnetted properly you can reduce the size of the routing table in each area. You can also use totally stub areas where only a default route is injected into an area. The other advantage is a topology change in one area doesn't cause an SPF calculation to happen in the other areas.

I am coming straight to the point.

• Multiple areas in a large network reduce your routing tables on each router and therefore fewer requirements on router memory and CPU.

 

• Route instability due to route withdrawals is limited to single areas and do not affect the whole network as in the case with a single area topology.

In single area the communication between routers is done in its own area which is mentioned in routing table but in multiple area the communication is done in neighbour area which is mentioned in routing table.

It means Area 0 can able to communicate with area 5 and Area 3 because in routing table Area 5 and Area 3 is neighbour Area of Area 0

In Simple Words,Multiple Ospf Area Network are used for extra Management Ability and to decrease routing Overhead,speed up convergence.

 

Dividing an ospf network into area decreases the lsdb size and limits propagation of link states updates.

 

 

 

the advantage of OSPF is reducing the routing table size by dividing the network into areas