H12-831_V1.0 Exam Dumps : HCIP-Datacom-Advanced Routing & Switching Technology V1.0

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

Comprehensive and Detailed In-Depth Explanation:

Understanding the OSPF Network Structure in the Question:

OSPF Areas & Routers:

Area 3: Contains R5 (which has loopback 10.0.5.5/32).

Area 1: Contains R6.

Area 2: Contains R4.

Area 0 (Backbone Area): Contains R1, R2, and R3 (which interconnect the other areas).

ACL 2000 Filtering Rule:

The ACL rule 2000 explicitly denies 10.0.5.5/32 from being imported.

The filter 2000 import command applies this filter to Area 0, preventing routes from Area 3 (including R5's loopback) from being learned by Area 0 routers (R1, R2, and R3).

Route Distribution Analysis:

R5 (Area 3):

R5 has 10.0.5.5/32 configured on its Loopback0.

Since OSPF is enabled, R5 advertises the route to R6 in Area 1.

R6 (Area 1) → R2 (Area 0, Backbone Router):

Without filtering, R6 would normally propagate 10.0.5.5/32 to R2 (since R2 is a backbone router in Area 0).

However, since ACL 2000 is applied in Area 0, R2 blocks this route from being imported.

Therefore, R2 does not learn 10.0.5.5/32.

R2 → R1 and R3 (Both in Area 0):

R2 would typically share any learned routes with R1 and R3 in Area 0.

But since R2 itself does not have 10.0.5.5/32, neither R1 nor R3 can receive it.

Thus, R1 and R3 also do not have 10.0.5.5/32 in their routing tables.

R4 (Area 2) is Unaffected:

Since R4 is in Area 2, it is not directly impacted by the filter applied in Area 0.

It can still receive the route via another path if redistribution is configured properly.

Final Conclusion:

R1, R2, and R3 do not have the 10.0.5.5/32 route due to the filter 2000 import command applied in Area 0.

R4 may still have the route since it is not affected by the filtering in Area 0.

Thus, the correct answer is:✅ R1, R3, R2 do not have the route 10.0.5.5/32 in their routing tables.