> > >>> Right, but how about multiple NUMBERED PtoP interfaces with the > >>> same local IP address? > >> I'd argue that if your configuration supports this, all but one of > >> the interfaces is unnumbered. > > > > Joakim, > IP address must be unique and assigned to one numbered IP interface > only. This has nothing to do with OSPF, it is requirement of a basic IP > addressing paradigm and covered in relevant IPv4 architecture documents > (no, I don't have a reference ready). > This 'limitation' is the reason why unnumbered interfaces were > invented in the first place. If "multiple NUMBERED PtoP interfaces with > the same local IP address" worked well then nobody would bother to have > unnumbered interfaces. > > Note that numbered interface by definition implies the interface has > mask <32 bits and that remote end has IP address from the same IP > subnet. If implementation allows configuration of IP address with mask > of 32 bits or no mask at all then this in fact is just implementation of > IP unnumbered interface where 'master' interface which owns the IP > address is not explicitly shown. Conceptually it would be IP unnumbered > nonetheless and should be treated by OSPF accordingly.
This is the case I am thinking on(numbered with mask=32), but I am treating it as a numbered interface in some cases and unnumbered in others and it works very well. The only difference OSPF makes on these two is adding Option 1 in the router LSA for the numbered one and unnumbered sends ifindex. Perhaps this conceptually a unnumbered I/F but one do not have to advertise it as such to get a working OSPF domain. Jocke _______________________________________________ OSPF mailing list [email protected] https://www.ietf.org/mailman/listinfo/ospf
