OSPF processes ?

[llukman.halimi]

I know that routers don't have to have the same process running in order to communicate with each other but my questions are I have 2.

     1) Can I have different processes numbers for the same area configured?

     2)Also can I have 1 routing process with different areas or does it have to be 1 routing process per area and you can't put 2 areas in 1 routing process?

[Reza Sharifi]

1) Can I have different processes numbers for the same area configured?

Yes, for example router-1 can have process id of 50 and router-2 can have process id of 100 and it work fine.  OSPF Process Ids are locally significant.

2)Also can I have 1 routing process with different areas or does it have to be 1 routing process per area and you can't put 2 areas in 1 routing process?

Yes, you can have multiple areas in the same process id.

HTH

[Joseph W. Doherty]

2)Also can I have 1 routing process with different areas or does it have to be 1 routing process per area and you can't put 2 areas in 1 routing process?

Yes, you can have multiple areas in the same process id.

Just to expand a little on this, the OSPF process is per OSPF AS.  I.e. you cannot selectively place OSPF areas into an OSPF process, you place OSPF areas in a particular OSPF AS, which you place in an OSPF process.

For example, if you had an OSPF topology with 3 areas, zero, 10 and 20, and you had 3 routers, one router with a connection to area zero, running OSPF process 1; the second router with a connection to area 10, running OSPF process 2; and the third router with a connection to area 20, running OSPF process 3; all 3 routers would be within the same OSPF AS (although not all the same LSAs and perhaps not all the same routes).

Generally, to avoid confusion, the same process number is used for the same OSPF AS on different routers.