Hi everyone,
Just want to check whether my thinking is correct on this.
A type 5 AS-external LSA originating in area 0 will not enter a stub area 1. A type 3 LSA, however, will be generated into area 1 by the ABRs sitting between area 0 and 1. Also, the ABRs will introduct a default route into area 1. Thus, in order to reach a route external to the AS, the default route will be used. Is everything I've said so far correct?
Next question: Will a type 3 LSA include routes from outside the AS? According to RFC 1247 the answer would seem to be no, but just want to be sure.
From RFC 1247: "A separate summary link advertisement is made for each destination (known to the router) which belongs to the AS, yet is outside the area..." and "AS external routes are never advertised in summary link advertisements."