To start OSPF process you have to specify the OSPF router. As of this writing, ospfd does not support multiple OSPF processes.
Enable or disable the OSPF process. ospfd does not yet support multiple OSPF processes. So you can not specify an OSPF process number.
type can be cisco|ibm|shortcut|standard More information regarding the behaviour controlled by this command can be found in draft-ietf-ospf-abr-alt-05.txt and draft-ietf-ospf-shortcut-abr-02.txt Quote: "Though the definition of the Area Border Router (ABR) in the OSPF specification does not require a router with multiple attached areas to have a backbone connection, it is actually necessary to provide successful routing to the inter-area and external destinations. If this requirement is not met, all traffic destined for the areas not connected to such an ABR or out of the OSPF domain, is dropped. This document describes alternative ABR behaviors implemented in Cisco and IBM routers."
This rfc2328, the sucessor to rfc1583, suggests according to section G.2 (changes) in section 16.4 a change to the path preference algorithm that prevents possible routing loops that were possible in the old version of OSPFv2. More specifically it demands that inter-area paths and intra-area path are now of equal preference but still both preferred to external paths.
This command specifies the OSPF enabled interface(s). If the interface has an address from range 192.168.1.0/24 then the command below enables ospf on this interface so router can provide network information to the other ospf routers via this interface.router ospf network 192.168.1.0/24 area 0.0.0.0
Prefix length in interface must be equal or bigger (ie. smaller network) than prefix length in network statement. For example statement above doesn't enable ospf on interface with address 192.168.1.1/23, but it does on interface with address 192.168.1.129/25.