ospf process id

[Mithun Sasi]

hai, can anyone help me to know the use of process id in ospf...?

[francisco_1]

The process ID is the ID of the OSPF process to which the interface belongs. The process ID is local to the router, and two OSPF neighboring routers can have different OSPF process IDs. (This is not true of Enhanced Interior Gateway Routing Protocol [EIGRP], in which the routers need to be in the same autonomous system). Cisco IOS® Software can run multiple OSPF processes on the same router, and the process ID merely distinguishes one process from the another. The process ID should be a positive integer. In this example, the process ID is 1.

[Ganesh Hariharan]

hai, can anyone help me to know the use of process id in ospf...?

Hi,

The process ID is the ID of the OSPF process to which the interface belongs. The process ID is local to the router, and two OSPF neighboring routers can have different OSPF process IDs.

Cisco IOS® Software can run multiple OSPF processes on the same router, and the process ID merely distinguishes one process from the another. The process ID should be a positive integer.

Hope to help !!

If helpful do rate the post

Ganesh.H

[Jon Marshall]

mits.sasi wrote:
hai, can anyone help me to know the use of process id in ospf...?

Mithun

The OSPF process id is locally significant on the router. Unlike EIGRP for example, the process id does not have to match between 2 neighbors for a neigborship to establish.

You can run multiple OSPF processes on the same physical router and the process id would be how the router distinguishes between the processes. Also when redistributing OSPF into another routing protocol you need to specify the process id.

Note that running multiple OSPF processes on the same router is not normally recommended as OSPF can be quite heavy on the router rseources.

Jon

[Kevin Dorrell]

In complex routing architectures you might want to have two (or more) completely seperate OSPF routing processes, one serving one set of interfaces and one serving a different set of interfaces.  These processes can be distinguished by means of the process id.  They will operate entirely independently of each other (unless you choose to redistribute routes between them), and will hold completely seperate link-state databases.  They will pass "like ship in the night" without any interference from each other.

Kevin Dorrell

Luxembourg

[ZacharyBall7934]

So to what Kevin is saying, is that a way to split the LSDB without having different areas?

[Joseph W. Doherty]

No, it's like having two (or more) different routing protocols on the same router (and as mentioned by others, you can redistribute between them, as you might between different routing protocols but without any issues due to different attributes supported by different routing protocols). Different OSPF router process IDs create a whole different OSPF routing domain on the router (i.e. more then area LSDBs). As also mentioned by the other posters, between OSPF routers, within the same OSPF routing domain (i.e. OSPF neighbors) do not need to have the same process ID (if you do this though, generally you would use the same router process ID for routers in the same OSPF domain).

Also like different routing protocols on the same router, on the same router all the different OSPF router ID routes go into the same global routing table, although, by default, with the same AD!