An ABR is configured with 'area 1 range 10.0.0.0 255.255.0.0' but routers in area 1 still install the component /24 routes instead of the summarized /16. What explains why the summary is not selected in routing tables?
Choose an answer
Tap an option to check your answer.
Correct answer: Routers prefer more specific intra-area routes over a summarized inter-area Type-3 LSA.
Why this is the answer
OSPF's route selection process prioritizes more specific routes. Even if an ABR advertises a summarized Type-3 LSA (inter-area) for 10.0.0.0/16, routers within Area 1 will prefer the more specific 10.0.0.0/24, 10.0.1.0/24, etc., routes if they are directly connected or learned as intra-area routes (Type-1 or Type-2 LSAs). This is because intra-area routes are considered "closer" and more accurate. The 'area range' command correctly generates Type-3 LSAs for summarization. Summaries are indeed advertised into non-backbone areas. The 'ip ospf summary-address' command is for ASBRs summarizing external routes, not ABRs summarizing internal areas.
Pass your exam — without the endless answer hunt
Get every verified question and explanation for this exam in one place, and save hours of prep. 1,000+ certifications · 20+ languages · free to start.
Pass your exam faster → No card needed