diff ospf process id

[rpalacio]

If we connect 2 layer 3 switch with multiple vlans in each, both running ospf but of different process id, what will happen..

am not so clear about this process id. pls help

[Georg Pauwen]

Hello,

if you run different OSPF process IDs, you need to mutually redistribute, otherwise the routes from each L3 switch will not be seen by the respective other L3 switch.

Is there a specific reason why you want to run two process IDs ?

Regards,

Georg

[rpalacio]

YES,the AS admin is not providing me the far end switch config..i just know about the ip range in my area and the area number as of the moment.

[rpalacio]

forgot to ask, with this scenario, if intervlan routing is working find, i should still be able to reach the interface of the far end switch where my core is connected right...thats my main problem actually...i couldnt reach that part.

[bratager]

Check link for more details, below is the information regarding the process ID. The layer 3 switches should still be able to communicate and exchange routes if they have different process IDs as long as the proper networks/interfaces are defined under the OSPF process.

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, unlike Enhanced Interior Gateway Routing Protocol (EIGRP) where the routers need to be in the same Autonomous System (AS). Cisco IOS 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.

http://www.cisco.com/warp/public/104/17.html

[rpalacio]

whats the purpose then of using different process id? other advise above says i need to redistribute if i used diff proc id..on your explanation above u said i should be able to communicate..

ill go thru the link u provided..thx for that, but meantime, please elaborate more..

thx

[ipotts]

The reply that said you need to redistribute assumed you had two ospf process ids on the one router. However, in your case you one process id on router1 and another process id on router2. Since the process id is local to the router, router1 and 2 will communicate with no need to redistribute.

[rpalacio]

so you are saying that i can put any process id i want..so whats the rule? what if i use the same process id the far end switch is using...

look my prob is i cant establish neighbors..so am tryin to figure out if i need at all the pocess id beeing used at the far end switch and use the same in my core..

[bratager]

The process IDs do not need to be the same (although it is generally good practice for documentation and simplicity). As long as you have the OSPF process on the router and the networks are properly defined OSPF should work. What issue are you seeing, are neighbors not forming?

[bratager]

Sorry, just noticed that you said the neighbors are not forming. What is the status when you do a "sh ip ospf neigh"

[ruwhite]

debug ip ospf adjacency is going to be your best bet for figuring out why the adjacency won't form--it's not because of the process ID, since the process ID isn't carried anyplace in the OSPF packets.

It could be:

-- hello time

-- hold time

-- mtu

-- area

-- area type

Or a smattering of other things--but those are the most common.

:-)

Russ.W