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

Step 1: Understanding OSPF Areas and Summarization

Area 1 (NSSA - Not So Stubby Area)

Allows external routes but converts Type-5 LSAs into Type-7 LSAs.

External routes must be translated by an ABR into Type-5 LSAs before being propagated into other areas.

Area 2 (Common Area - Regular OSPF Area)

Supports both inter-area and external routes.

asbr-summary 10.0.4.0 255.255.255.0 Command

This command summarizes all external routes within 10.0.4.0/24 into a single summarized route.

Since it is applied on R1 and R3, these routers will advertise 10.0.4.0/24 instead of 10.0.4.4/32 to their respective areas.

Step 2: Route Distribution Analysis

R4 (Originating Router in NSSA - Area 1)

R4 injects 10.0.4.4/32 as a Type-7 LSA into Area 1.

R1 (ABR between Area 1 & Area 0, Summarizing Route)

Since R1 is an ABR, it translates Type-7 LSAs from Area 1 into a summarized Type-5 LSA (10.0.4.0/24) for Area 0.

✅ R1 has 10.0.4.0/24 in its routing table.

R2 (Inside Backbone Area 0, No ASBR Summary Applied Here)

R2 only receives Type-5 LSAs from R1 but does not summarize them.

Since R2 is not explicitly summarizing, it will likely still see 10.0.4.4/32 rather than 10.0.4.0/24.

❌ R2 does not have 10.0.4.0/24.

R3 (ABR between Area 0 & Area 2, Summarizing Route)

R3 is also an ABR and has the asbr-summary 10.0.4.0/24 command configured.

It will advertise the summarized route 10.0.4.0/24 into Area 2.

✅ R3 has 10.0.4.0/24 in its routing table.

R5 (Inside Area 2, No Direct Connectivity to External Routes)

Since R3 summarizes 10.0.4.0/24, R5 (inside Area 2) will receive only summarized routes.

✅ R5 has 10.0.4.0/24.

Final Answer: ✅ R1, R3 (Option A, C)

References:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 – OSPF Route Summarization

OSPF NSSA and Type-7 to Type-5 LSA Translation

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the Network Setup

PE1 (Provider Edge 1) is the gateway for network 192.168.1.1/24.

PE2 (Provider Edge 2) is the gateway for network 192.168.2.1/24.

A cloud-based backbone connects PE1 and PE2.

To verify end-to-end communication, engineers need to check reachability between PE1 and PE2.

2. Evaluating Each Answer Option

Option A: "Configuring NQA on PE1 and PE2, with the destination address being the IP address of each other."

✅ Correct.

NQA (Network Quality Analysis) is a network testing tool that allows connectivity testing between two devices.

Configuring NQA between PE1 and PE2 will verify end-to-end reachability.

Option B: "On PE1 and PE2, checking whether the ARP table contains the ARP entry of the peer network segment."

❌ Incorrect.

ARP (Address Resolution Protocol) is only used for resolving MAC addresses within the same broadcast domain.

Since PE1 and PE2 are in different network segments (separated by a routed network), they will not have ARP entries for each other.

Instead, routing entries should be checked, not ARP.

Option C: "On PE1, using 192.168.1.1 as the source address to ping 192.168.2.1."

✅ Correct.

A simple ping test using the source address of PE1 (192.168.1.1) to reach PE2 (192.168.2.1) will verify whether routing between the two locations is functional.

Option D: "On PE1 and PE2, checking whether there are routes to each other’s network segment in the routing tables."

✅ Correct.

If routing is not configured correctly, PE1 and PE2 will not know how to reach each other.

Checking the routing table ensures that both PEs have the correct next-hop information.

Final Answer:

✅ A, C, and D are correct.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Using NQA for Network Connectivity Testing

Verifying Routing Table Entries for Inter-Network Communication

Understanding ARP and Its Limitations in Routed Networks

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