Well, I guess we are telling the same thing, however lets try to visualize a bit to clear off the inbound / outbound interface part.  R11- 1.1.1.1R13 - 3.3.3.3 With default Costs :- R11#sh ip rou 3.3.3.3Routing entry for 3.3.3.3/32Known via "ospf 1",...

Yes, if you are looking at the direction of the route update (incoming interfaces) or as RFC 2328 states, "a cost is associated with the output side of each router interface" e.g.The route update from R3 would add the advertised cost from R3 + R2 (in...

STP Loopgaurd is used to prevent STP loops occuring due to unidirectional links.This feature is similar to UDLD, but it uses STP BPDU keepalives if there is a unidirectional link.Ideally loopguard should be enabled on all the interswitch links.