Can we use OSPF without backbone area?

If we are using multiple area design, then we must need to have area 0. It won't work without that. LSA 1 and 2 are generated to exchange routers within the area and LSA 3 will only be generated if router is connected to area 0. 

If we are using single area ospf, we can use any area other than area0, but in multi area ospf backbone area is must.

No, we cannot use OSPF without backbone area.While configuring OSPF, two tings must be kept in mind:

1: there should be backbone area (area 0)

2: All other area should be directly connected to backbone area (area 0)

If we are using single area ospf, we can use OSPF without backbone area but If we are using multiple area design, then we must need to have area 0.

Answer is Yes we can use but it depends on the network design, suppose we have acquired a company and they are also running OSPF then we can connect their Area to our OSPF domain with the help of Virtual Link. Although it’s not the recommended design but yes we can do it.

In Single area ospf we can use any area but not area 0 and if we are using multiple areas then ospf backbone area compulsory.

 

 

 

Yes, we can if we are configuring only single area non-zero. All routers in same area will share same/all routes of that area (intra area routes).

 

IF WE ARE USING ONLY ONE AREA THEN BACKBONE AREA IS NOT REQUIRED. But for interarea communication we need backbone area. This is also loop avoidance technique (by - design) used in OSPF 

Yes in one safe condition, if you are using one area only for all your network.

but you need to understand the area types if you wanna do redistribution/default-route and etc ... 

we can run OSPF if its single are, but if you required to connect with different areas you have to need backbone area.

NO,

Backbone area is area 0.Until and unless we use area 0 between two different ospf areas they cannot communicate.