Comprehensive and Detailed In-Depth

To determine the cost value of the route 10.0.35.0/24 in the routing table of R1, let's analyze the possible shortest paths from R1 to R3 (which owns the 10.0.35.0/24 network) based on the given OSPF link costs:

Path 1: R1 R2 R3

R1 to R2: Cost = 20

R2 to R3: Cost = 10

Total Cost = 20 + 10 = 30

Path 2: R1 R4 R3

R1 to R4: Cost = 10

R4 to R3: Cost = 10

Total Cost = 10 + 10 = 20 (Lowest cost path)

Path 3: R1 R5 R3

R1 to R5: Cost = 10

R5 to R3: Cost = 10

Total Cost = 10 + 10 = 20 (Equal-cost path)

Final Calculation:

The two best equal-cost paths (R1 R4 R3 and R1 R5 R3) have a cost of 20.

Since OSPF supports equal-cost multi-path (ECMP) routing and maximum load-balancing 8 is enabled, OSPF will install both routes into the routing table with the same cost of 20.

The path R1 R2 R3 has a higher cost (30) and will not be chosen.

Final Answer: 20 (Option C)

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 -- OSPF Route Calculation & Load Balancing

OSPF Equal-Cost Multi-Path (ECMP) and Route Selection

OSPF Fast Reroute (FRR) Mechanism