Re: Multiple OSPF processes having same router-id ?

Just as some additional information (more relevant for CCIE candidates),
some of my notes from odd-ball OSPF stuff:

/ "A very interesting point on the topic of router-id's is that only one
OSPF process on a router can have a particular router-id, i.e. they
can't be shared amongst separate OSPF processes which may be running on
the local router. This can be used as a last ditch effort to try and
influence the router-id if lab restrictions mean we can't manually
change the router-id using the "standard methods": //
////
//Configure a dummy OSPF process which will "take and hold" the highest
loopback or normal interface address. //
////
//Configure the actual / real OSPF process which we are intending to
actually use. Since the highest interface address is already "owned" by
the dummy OSPF process, this second process will have to use the next
available one. //
////
//The order of the configuration for the OSPF processes is important in
this trick. The dummy OSPF process must be configured to appear first in
the running-configuration. Also for the most part, the OSPF process ID
is only locally significant except some cases with MPLS PE-CE where the
DOMAIN-ID is derived from the OSPF process-ID. //
////
//This trick is also good for preventing an OSPF process from running at
al, i.e. starve the real OSPF process from acquiring a router-ID by
assigning them all to dummy processes. //"/

*Nov 24 11:00:33.511: %OSPF-4-NORTRID: OSPF process 2 failed to allocate
unique router-id and cannot start

Billy

On 02/18/15 11:35, Rakesh M wrote:
> Yes Billy,
>
> I am not sure how i tested before but i can see the parser is throwing
> an error about usage of same router-id on Multiple processes.
>
> R5(config)#router ospf 20
> R5(config-router)#router-id 20.20.20.20
> R5(config-router)#exit
> R5(config)#
> R5(config)#router ospf 21 vrf ABC
> R5(config-router)#router-id 20.20.20.20
> % OSPF: router-id 20.20.20.20 in use by ospf process 20
>
> Thanks
>
> Thanks
> Rakesh Madupu
> JNCIE-SP #02079
>
> On Tue, Feb 17, 2015 at 5:48 PM, Billy Singh <billysingh_at_ipanyany.com
> <mailto:billysingh_at_ipanyany.com>> wrote:
>
> Not sure about "real-world" applications but I just knocked a quick
> config up in a lab environment and was unable to manually
> configure the
> same OSPF router-id across multiple OSPF processes (Global and
> VRF); the
> IOS parser did prevent me from doing so:
>
> R10(config-if)#router ospf 1 vrf CUST1
> R10(config-router)#router-id 1.1.1.1
> % OSPF: router-id 1.1.1.1 in use by ospf process 100
> ...
> *Feb 17 11:59:37.282: %OSPF-4-NORTRID: OSPF process 1 failed to
> allocate
> unique router-id and cannot start
> ...
> R10(config-router)#do sh ip os | i [Pp]rocess
> Routing Process "ospf 100" with ID 1.1.1.1
> %OSPF: Router process 5 is not running, please configure a router-id
> %OSPF: Router process 4 is not running, please configure a router-id
> %OSPF: Router process 3 is not running, please configure a router-id
> %OSPF: Router process 2 is not running, please configure a router-id
> %OSPF: Router process 1 is not running, please configure a router-id
>
> R10(config-router)#do sh ver | i IOS
> Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M),
> Version 15.4(2)T, DEVELOPMENT TEST SOFTWARE
>
> What is your hardware platform and IOS version?
>
> Billy
>
> On 02/17/15 21:45, Rakesh M wrote:
> > Hi,
> >
> > Within Cisco Routers, if we have multiple OSPF processes
> (running in global
> > and as well at VRF level) , can we define same router-id for all
> these OSPF
> > processes ?
> >
> > I tried assigning and i have not got any parser errors from the
> device nor
> > there was an impact on Neighbor formation process ?
> >
> > Would there be any design Reason for this choice or for not to
> opt for this
> > choice ?
> >
> > Thanks
> > Rakesh Madupu
> > JNCIE-SP #02079
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> >
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Received on Wed Feb 18 2015 - 12:20:52 ART