OSPF process/router ID

Cider

Hi Guys,
So I know that your process ID does not have to be the same for OSPF to neighbour.
Now without giving too much away there was a question regarding the ID being a problem. Do they refer to the process ID or router ID? I presume the router ID cannot be the same - I am trying to recreate this in gns3 but it wants me to clear the process and I can never get back into the router.

Any help appreciated.

atorven

Correct, the router ID can't be the same but the process ID can.

Cider

But the process ID can also be different, correct?

The area must be the same?

I dont know why i thought it has to be the same. Getting confused with EIGRP.

networker050184

The process ID is locally significant.

Area must be the same on a link.

Cider

So you can create 2 different process ID on the same router and set the same parameters and it doesnt make any difference?

Routing Protocol is "ospf 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 192.168.1.2
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 1
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
Distance: (default is 110)


Routing Protocol is "ospf 200"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 172.16.1.2
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 1
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
Distance: (default is 110)

VinnyCisco

The only difference is you are now running 2 local OSPF processes on that specific router.

Dieg0M

Contrary to what most people will tell you here, the process ID is NOT always locally significant. When creating an OSPF Sham links in a L3 VPN MPLS environment, the process ID is actually really important. This is not something that you have to be concerned in your CCNA/CCNP studies but keep this in the back of your head for the future.

networker050184

Sure there are some advanced features, but for the sake of OSPF sanity here at the CCNA level it's best not to confuse people. The answer to pretty much every question can be maybe or it depends if you really get into it.

Cider

Thanks guys - appreciate the answer/s.