Consider the Autonomous System pictured in Figure 2. No OSPF areas have been configured. A single metric is shown per outbound interface, indicating that routes will not vary based on TOS. The calculation of Router RT6's routing table proceeds as described in Section 2.1. The resulting routing table is shown in Table 12. Destination types are abbreviated: Network as "N", area border router as "BR" and AS boundary router as "ASBR".
There are no instances of multiple equal-cost shortest paths in this example. Also, since there are no areas, there are no inter-area paths.
Routers RT5 and RT7 are AS boundary routers. Intra-area routes have been calculated to Routers RT5 and RT7. This allows external routes to be calculated to the destinations advertised by RT5 and RT7 (i.e., Networks N12, N13, N14 and N15). It is assumed all AS external advertisements originated by RT5 and RT7 are advertising type 1 external metrics. This results in type 1 external paths being calculated to destinations N12-N15.