ip ospf network command

Question:

When do we use the following WS-C3750X-24P-L Price ospf commands?

I've been working within GNS and it seems that ospf automatically recognizes, based on the media type, what the network type should be..

So, I don't understand why these commands exist?

1) Broadcast (Cisco Extension)

2) non-Broadcast (RFC-compliant mode)

3) Point-to-multipoint (RFC-compliant mode)

4) point-to-multipoint non-broadcast (Cisco extension)

5) POint-to-point (Cisco extension)

Do they exist more for a Frame Relay purpose

Answer:

they exist to change the default network type that the device configured on the interface, for example:

-loopbacks are treated as stubs so they are advertised with a /32 by default and if you want to override this then change the network type

-you have 2 routers connected via an ethernet link so change the network type to be point-to-point as here you don't need any DR/BDR

-you have a frame-relay config with devices having different but compatible network types but the adjacency doesn't come up because of different hello/dead timers then either change the network type to modify these timers or change the hello/dead to be equal.

I'm sure that you'll find other WS-C3750V2-48TS-S usages for these network types.