same of different OSPF process ID?

[sleepingandrew]

Hi,

I would like to ask should the OSPF process ID the same for all the routers within a single area? I have seen some examples in cisco website where each router within area 0 uses a different OSPF process ID. Can anyone clarify this for me? Thanks.

Andrew

[pkhatri]

G'day,

The OSPF process ID is a locally signicant identifier which serves to distinguish OSPF processes when you have more than one OSPF process configured on a single router.

Also, the process ID is not carried within any of the OSPF packets so neighboring routers have no way of discovering this.

Therefore, you can select different process IDs on different routers without any problems.

Cheers,

Paresh.

[Richard Burts]

OSPF will work very well whether the process ID is the same or is different within the area.

The only time that it really matters much what the value of the process ID is, is when there is more than one OSPF process running on the router.

Even though OSPF does not care, you may want to consider establishing a management policy about the value of the OSPF process ID. If all routers within the area (or even all routers within the domain) have the same value for process ID it may make configuration management and troubleshooting easier. If the value of process ID is to be different, what will be used to determine the unique value to be used on each router (would it be related to the value of the address of the loopback interface, or to some other value).

My personal opinion is that consistency and predictability are good things, and I prefer to have OSPF have the same process ID. But OSPF will run well either way.