Re: ospfd participating in a stub area
On Tue, Feb 06, 2007 at 11:09:45PM -0500, Nick Davey wrote: The passive keyword will advertise a network as a stub area, however as the interface is passive it cannot form a neighbor relationship with any other router in that area, or on that interface. From the man pages it would appear there is no way to specify an area as stub however Claudio or Henning would be able to help you out more than I would. Stub areas have nothing to do with passive interfaces. A stub area is an area that does not get flooded with AS-external LSA. This is used to allow crappy routers with limited memory into larger networks. Ospfd does currently not support stub areas. We did not consider them important enough to be something that had to be implemented ASAP. Some bits are present but more work is needed and it is on the todo list. -- :wq Claudio Best Regards, Nick Lars Hansson wrote: Nigel Roberts wrote: Is it possible to configure an area in ospfd.conf to be a stub area? Yes, use the passive option. It's in the ospfd.conf man page. --- Lars Hansson
Re: ospfd participating in a stub area
On Wednesday 07 February 2007 00:53, Nigel Roberts wrote: Is it possible to configure an area in ospfd.conf to be a stub area? I have an area where all particpating routers (ciscos) are configured to treat it as a stub ie. router ospf 1234 ... area 1 stub ... What excactly is the purpose of this? Is it some cisco trick to save memory or does it have a real purpose? Normaly when routers form adjacency the network is not considered a stub network any more, hence it can be used to forward traffic. /Esben
Re: ospfd participating in a stub area
On Wed, 07 Feb 2007 at 13:57:52 +0100, Esben Norby wrote: What excactly is the purpose of this? Is it some cisco trick to save memory or does it have a real purpose? It's not a cisco trick as such, since it's defined in the OSPF RFC along with NSSA (not so stubby areas) and totally stubby areas. It is designed to save CPU and memory resources. Normaly when routers form adjacency the network is not considered a stub network any more, hence it can be used to forward traffic. Stub areas are not to be confused with stub networks. Stub networks are what is formed when you define an interface as passive. A stub area is what is formed when the area border router for that area no longer floods LSAs for AS-external routes into the area. Thanks to Claudio for clarifying the situation. It's not a big deal really - I was simply doing some testing with stub areas and wanted to make sure of what was possible. Regards, Nigel
ospfd participating in a stub area
Is it possible to configure an area in ospfd.conf to be a stub area? I have an area where all particpating routers (ciscos) are configured to treat it as a stub ie. router ospf 1234 ... area 1 stub ... There doesn't appear to be a way of setting a similar option in ospfd.conf, so when I start ospfd I get errors like the following: recv_hello: ExternalRoutingCapability mismatch, interface vlan18 and no neighbour relationships are established. This is because all LSAs sent by the ABR have the ExternalRoutingCapability option set as per the OSPF specs for a stub area and ospfd appears to be hardcoded to drop these. Any suggestions welcome. Regards, Nigel
Re: ospfd participating in a stub area
Nigel Roberts wrote: Is it possible to configure an area in ospfd.conf to be a stub area? Yes, use the passive option. It's in the ospfd.conf man page. --- Lars Hansson
Re: ospfd participating in a stub area
The passive keyword will advertise a network as a stub area, however as the interface is passive it cannot form a neighbor relationship with any other router in that area, or on that interface. From the man pages it would appear there is no way to specify an area as stub however Claudio or Henning would be able to help you out more than I would. Best Regards, Nick Lars Hansson wrote: Nigel Roberts wrote: Is it possible to configure an area in ospfd.conf to be a stub area? Yes, use the passive option. It's in the ospfd.conf man page. --- Lars Hansson
