Comprehensive and Detailed In-Depth Explanation:
Step 1: Analyzing the Primary Path
* The given network uses IS-IS Auto FRR, which ensures a backup route in case of failure.
* The shortest path from R1 to 10.0.3.3/32 is calculated based on the OSPF link costs:
* Path 1 (Primary Path): R1 # R2 # R3
* Cost: 10 (R1#R2) + 5 (R2#R3) = 15 #
Step 2: Checking the Backup Path
* The statement claims that the backup path is R1 # R4 # R2 # R3. Let's calculate the cost:
* Path 2 (Backup Path via R4): R1 # R4 # R2 # R3
* Cost: 10 (R1#R4) + 50 (R4#R2) + 5 (R2#R3) = 65 # (Too high)
* The backup path should be an alternative shortest path that is as close as possible to the primary path in cost.
* R1 # R4 # R2 # R3 is not a feasible backup path because the cost (65) is significantly higher than the primary path (15).
Step 3: Correct Backup Path Selection
* If IS-IS Auto FRR is enabled, a feasible backup path should have a cost close to the primary path.
* In this scenario, no viable alternative path meets the Auto FRR requirements efficiently.
* The given backup path is incorrect.
Final answer: # FALSE (Option B)
References:
* HCIP-Datacom-Advanced Routing & Switching Technology V1.0 - IS-IS Auto FRR Mechanism
* OSPF Route Selection and Fast Reroute Principles
* OSPF and IS-IS Path Cost Calculation