> > I have a very specific problem on an unnumbered point to point link for an > IPsec tunnel. This link is associated to another IP interfaces address on the > device to borrow an IP (source) address for the packets. The link itself (as > being unnumbered has no IP subnet assigned). > Which option of the following in “12.4.1.1. Describing point-to-point > interfaces” would apply for the stub area advertisement? > In addition, as long as the state of the interface > is "Point-to-Point" (and regardless of the > neighboring router state), a Type 3 link (stub > network) should be added. There are two forms that > this stub link can take: > Option 1 > Assuming that the neighboring router's IP > address is known, set the Link ID of the Type 3 > link to the neighbor's IP address, the Link Data > to the mask 0xffffffff (indicating a host > route), and the cost to the interface's > configured output cost.[15] > Option 2 > If a subnet has been assigned to the point-to- > point link, set the Link ID of the Type 3 link > to the subnet's IP address, the Link Data to the > subnet's mask, and the cost to the interface's > configured output cost.[16] > I would read that option 2 would not apply as the link is unnumbered therefore > no subnet has been assigned to that link (even though an associated address > is set). > For my specific PtP case the neighbor address is known as the tunnel endpoint > is manually configured (though not in any local network) therefore I can use > this for the Stub entry. > Is that reading correct?
There was a discussion about this some months ago(started by me) on this subject. The short answer is that for unnumbered links you don't send Option 1 nor Option 2. The spec is a bit unclear but that is what the list concluded. > What if we are talking about a virtual link? > Although a virtual link acts like an > unnumbered point-to-point link, it does have an associated IP > interface address. This address is used as the IP source in > OSPF protocol packets it sends along the virtual link, and is > set dynamically during the routing table build process. > Is has no known neighbor router IP as it knows only the neighbor routers > router-ID (not IP) and it has no subnet assigned to the virtual link (though > an associated IP). How should the stub advertisement look like - which of the > options apply? > Regards > Juergen Arlt > ------------------------------------------------- > Juergen Arlt > Nortel GmbH > Senior Network Solutions Engineer > Global Network Technical Support > Mittlerer Pfad 26 > 70499 Stuttgart > Germany > Tel: +49 (711) 1394361 > ESN: 595 4361 > Fax: +49 (711) 1394330 > ------------------------------------------------- > _______________________________________________ > OSPF mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ospf _______________________________________________ OSPF mailing list [email protected] https://www.ietf.org/mailman/listinfo/ospf
