OSPF and areas

Tricon7

I think I'm understanding OSPF a little better now. I had thought that one OSPF area was confined to one network; but I see that one area can include multiple networks. Is this correct?

Netstudent

When you say network, do you mean a single subnet or a single administrative entity like an AS?

The areas are there to hierarchically separate areas of the network to decrease routing tables size, decrease processor cycles on SPF calculations, and decrease network flooding. IN OSPF you manually summarize at area boundries and AS boundries, whereas in EIGRP can summarize anywhere.

srg

Tricon7 wrote:

I think I'm understanding OSPF a little better now. I had thought that one OSPF area was confined to one network; but I see that one area can include multiple networks. Is this correct?

Yup, that's correct, an area can include multiple networks.

Cucumber

Yeah, OSPF areas are made of networks and routers.

Inside each area, OSPF routers build a tree with the networks and routers contained in such area.

Each OSPF router is a node in the tree. Also, each multiaccess network is a node; i.e. each ethernet network is a node.