Flat/Single Area OSPF network is not a problem!
Flat OSPF network, or single area OSPF networks are real. In fact most of the OSPF network today deployed, is flat OSPF networks. But how many routers can be placed safely in an OSPF area ? Any number from the real world OSPF deployment ? I will share in this post.
Let me explain what it is first and then will share you some numbers from the real network which I engaged recently.
As you might know, OSPF has two levels of hierarchy. Backbone and Non-Backbone areas.
Why Non-Backbone Areas are used in OSPF?
The reason is scalability and manageability. At least in theory. I don’t see so many multi area OSPF design though I teach in very detail in my CCDE classes. But that is for the exam purpose.
There are some very large scale networks use OSPF for scalability, so, IP but satellite (Sometimes called an Access POP) POPs are in Non-Backbone area they place.
But there is manageability aspects of having multi area OSPF design. They group their slow speed access and metro or aggregation networks in different OSPF areas and place high speed backbone/core routers in a backbone OSPF area (Area 0).
But, we generally forget Continue reading
