In RFC 2328, Chap 12.4.1.1, reads:
12.4.1.1. Describing point-to-point interfaces
For point-to-point interfaces, one or more link
descriptions are added to the router-LSA as follows:
o If the neighboring router is fully adjacent, add a
Type 1 link (point-to-point). The Link ID should be
set to the Router ID of the neighboring router. For
numbered point-to-point networks, the Link Data
should specify the IP interface address. For
unnumbered point-to-point networks, the Link Data
field should specify the interface's MIB-II [Ref8]
ifIndex value. The cost should be set to the output
cost of the point-to-point interface.
o 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 have a hard time figuring out what to do with Option 1 and Option 2 for
unnumbered
PtoP interfaces. I don't think either of them applies to an unnumbered link so
I wonder if one should omit both Options?
However 12.4.1.1 starts with:
For point-to-point interfaces, one or more link
descriptions are added to the router-LSA as follows
which could be read as there must always be one or more items and as the first
item needs to have a fully adjacent router you could end up with zero items in
the LSA for
a PtoP interface.
So what should one do?
Jocke
_______________________________________________
OSPF mailing list
OSPF@ietf.org
https://www.ietf.org/mailman/listinfo/ospf
