Free Huawei H12-831_V1.0 Practice Exam with Questions & Answers

Comprehensive and Detailed In-Depth Explanation:

Network migration requires detailed planning to prevent service disruptions and rollback failures.

Potential issues due to poor preparation:✅ A. No network cable tester available → Hard to diagnose whether the issue is hardware or cable-related.✅ B. No backup of configuration files → If migration fails, services cannot be restored quickly.✅ C. No spare hardware available → Hardware failures may cause long service downtimes.✅ D. Engineers arriving late → Delays may lead to extended service downtime or missed migration windows.

???? Reference: HCIP-Datacom Advanced Routing & Switching Technology – Migration Best Practices

Comprehensive and Detailed In-Depth Explanation:

1. Understanding MPLS LDP (Label Distribution Protocol)

LDP (Label Distribution Protocol) runs over TCP port 646.

LDP uses the transport address (Loopback0 in this case) to establish TCP sessions between neighbors.

For an LDP session to be established, both routers must:

Enable LDP on the interface (GE0/0/1).

Allow TCP traffic on port 646 (used for LDP adjacency formation).

2. Analyzing the Issue and Possible Causes

The figure shows a successful ping from R2 to R1’s Loopback0 (10.0.1.1/32).

This means basic IP connectivity between R1 and R2 is working.

OSPF is properly advertising Loopback0 addresses between the routers.

The problem must be related to LDP itself, not general IP reachability.

3. Evaluating Each Answer Option

Option A: "R1’s GE0/0/1 rejects packets with the destination IP address 10.0.2.2."

Incorrect.

The ping test in the figure shows successful replies from 10.0.1.1 to 10.0.2.2, meaning packets to 10.0.2.2 are not being rejected.

This is NOT the cause of the LDP failure.

Option B: "MPLS LDP is not enabled on R2’s GE0/0/1."

Correct.

If LDP is not enabled on R2’s GE0/0/1, then R1 and R2 cannot form an LDP session.

MPLS LDP must be enabled on both interfaces for label exchange.

This is a valid cause of the issue.

Option C: "R2’s GE0/0/1 rejects packets with TCP destination port 646."

Correct.

LDP operates over TCP port 646, so if R2’s GE0/0/1 has a firewall or ACL blocking TCP port 646, then LDP will fail.

Blocking TCP 646 on R2’s interface would prevent the session from establishing.

This is another valid cause of the issue.

Option D: "R1’s GE0/0/1 rejects packets with UDP destination port 646."

Incorrect.

LDP does not use UDP; it uses TCP port 646.

This is not a valid cause of the issue.

Final Answer:

✅ B and C are correct.

HCIP-Datacom-Advanced Routing & Switching Technology References:

MPLS LDP Session Establishment and TCP 646 Dependency

How OSPF Advertises Loopback0 for LDP Transport

Common LDP Debugging Techniques and ACL Issues

Restrict → Discards the packets that trigger static MAC address flapping and reports an alarm.

Protect → Discards the packets that trigger static MAC address flapping only and does not report an alarm.

Shutdown → Sets the interface state to error-down and reports an alarm.

Comprehensive and Detailed In-Depth Explanation:

1. Understanding Port Security Modes

Port security is used to control access on a switch port based on MAC addresses. If a MAC address violation occurs (e.g., static MAC address flapping), the switch can take different actions based on the configured security mode.

Security Mode

Description

Restrict

Drops the violating packets and logs the violation by generating an alarm.

Protect

Drops the violating packets but does not generate an alarm.

Shutdown

Places the interface into error-disabled (error-down) state and logs an alarm.

2. Matching Each Security Mode with Its Operation

Protect Mode:

The switch drops the packets from the unauthorized MAC address.

No alarm is generated or logged.

Correct Mapping: "Discards the packets that trigger static MAC address flapping only and does not report an alarm."

Restrict Mode:

The switch drops the packets from the unauthorized MAC address.

An alarm is generated and logged in the system.

Correct Mapping: "Discards the packets that trigger static MAC address flapping and reports an alarm."

Shutdown Mode:

The switch shuts down the interface by placing it into the error-down state.

An alarm is generated and logged.

Correct Mapping: "Sets the interface state to error-down and reports an alarm."

Comprehensive and Detailed In-Depth Explanation:

The display startup command is used to check the startup and running configuration details of a Huawei network device.

It provides information on:✅ Running system software (currently active firmware).✅ Running configuration file (current settings in use).✅ Startup system software (firmware that will load on reboot).✅ Startup configuration file (configuration that will be applied on reboot).✅ Paths of these files in the storage system.

This command helps network administrators ensure that the correct firmware and configuration files are used when the device boots.

???? Reference: HCIP-Datacom Advanced Routing & Switching Technology – System Management and Configuration Files

To determine the correct answer, we need to analyze how OSPFv3 handles Router LSAs (Type 1 LSAs) in a simple Area 0 topology like the one shown in the figure.

1. Understanding OSPFv3 Router LSAs (Type 1 LSAs)

Router LSAs (Type 1 LSAs) are generated by each router within an OSPF area to describe its own directly connected links.

Each router in an OSPF area generates exactly one Type 1 LSA.

The Link-State Database (LSDB) on a router contains LSAs from all routers in the same area.

2. Analyzing the Network in the Figure

There are 3 routers: R1, R2, and R3.

All routers are in OSPFv3 Area 0 (which is a single area).

Each of these routers generates one Router LSA (Type 1 LSA).

Since R2 is in the same area as R1 and R3, its LSDB contains the Router LSAs from itself, R1, and R3.

3. Conclusion

The LSDB of R2 contains 3 Router LSAs (one from each router: R1, R2, and R3).

Final Answer: 3

A = 50

B = 10

C = 20

Comprehensive and Detailed In-Depth Explanation:

Understanding OSPF Path Selection and Cost Calculation:

OSPF selects the shortest path (lowest cost) to the destination.

The OSPF cost is determined by the cumulative sum of interface costs along a path.

By assigning specific costs to A, B, and C, we can influence OSPF’s path selection to meet the desired routing behavior.

Step-by-Step Analysis of Required Traffic Flow:

1. Traffic from PC1 to PC2 must take the route:

PC1 -> R1 -> R3 -> R2 -> PC2

To force traffic through R3, the cost of the direct link R1 -> R2 (Cost-A) must be higher than the alternative path via R3.

We assign Cost-A = 50 (high cost) to discourage direct routing from R1 -> R2.

The cost of R1 -> R3 (Cost-C) should be lower, so we assign Cost-C = 20.

The cost of R3 -> R2 (default Cost-20) remains unchanged.

Total cost via R3: 20 (R1->R3) + 20 (R3->R2) = 40, which is less than the direct link of 50, so OSPF prefers this path.

✅ Traffic follows: PC1 -> R1 -> R3 -> R2 -> PC2

2. Traffic from PC2 to PC1 must take the route:

PC2 -> R2 -> R1 -> PC1

We need to make R2 -> R1 (Cost-B) the best (lowest cost) route for return traffic.

Assign Cost-B = 10 (low cost).

This ensures that R2 prefers the direct path R2 -> R1 instead of R2 -> R3 -> R1 (which costs 20+20=40).

✅ Traffic follows: PC2 -> R2 -> R1 -> PC1

Final Cost Assignments for Correct Routing Behavior:

Cost

Assigned Value

Reason

Cost-A (R1 -> R2)

50

High to discourage direct R1->R2 routing

Cost-B (R2 -> R1)

10

Low to ensure PC2->PC1 prefers direct R2->R1

Cost-C (R1 -> R3)

20

Medium to encourage R1->R3->R2 path

Key Takeaways:

Higher OSPF cost discourages path selection.

Lower OSPF cost encourages path selection.

By manipulating OSPF cost values, we achieve asymmetric routing between PC1 and PC2.

This aligns with OSPF path selection principles covered in HCIP-Datacom certification.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Huawei HCIP-Datacom Official Certification Guide, Chapter on OSPF Cost Calculation and Path Selection.

Huawei Enterprise Networking Training Materials, OSPF Path Optimization Techniques.

Huawei Datacom Configuration Guide, OSPF Cost and Traffic Engineering.