Comprehensive and Detailed In-Depth Explanation:
Step 1: Understanding OSPF Areas and Summarization
* Loopback0 on R5 has IP 10.0.5.5/32 and is advertised into OSPF.
* The abr-summary 10.0.5.0 255.255.255.0 command is applied in area 2 on R1, which means:
* Instead of advertising individual host routes (like 10.0.5.5/32), R1 advertises the summarized route 10.0.5.0/24 into Area 0 (Backbone).
* This summarized route is then propagated into other areas via Area 0 (Backbone).
Step 2: Analyzing the Routing Table of Each Router
* R5 (Originating Router in Area 2)
* R5 only knows 10.0.5.5/32 because it's the originating router.
* The abr-summary command does not affect R5 itself.
* # R5 does not have 10.0.5.0/24.
* R1 (ABR for Area 2, Summarizing the Route)
* R1 creates and advertises 10.0.5.0/24 into Area 0.
* This summary route is sent to other areas via Area 0.
* R2 (Connected to Area 0 & Area 1)
* Since R2 is part of Area 0 (Backbone), it receives 10.0.5.0/24 from R1.
* # R2 has 10.0.5.0/24 in its routing table.
* R3 (Connected to Area 0 & Area 2)
* Since R3 is also connected to Area 0, it receives the summary route 10.0.5.0/24 from R1.
* # R3 has 10.0.5.0/24 in its routing table.
* R4 (In Area 1, which is not directly connected to Area 2)
* R4 belongs to Area 1, and unless explicitly advertised through inter-area summarization, it will not have 10.0.5.0/24.
* Since no specific mention of summary advertisement into Area 1 is made, R4 does not get
10.0.5.0/24.
* # R4 does not have 10.0.5.0/24.
Final Answer: # R2, R3 (Option B, C)
References:
* HCIP-Datacom-Advanced Routing & Switching Technology V1.0 - OSPF Route Summarization
* OSPF Inter-Area Route Advertisement via ABRs
* OSPF Backbone (Area 0) Behavior and Route Distribution