H12-831_V1.0 Huawei HCIP-Datacom-Advanced Routing & Switching Technology V1.0 Free Practice Exam Questions (2026 Updated)

Comprehensive and Detailed In-Depth Explanation:

Understanding the BGP Network Topology in the Question:

EBGP Peering

Each router forms EBGP peer relationships with directly connected neighbors.

This is a fully meshed topology, meaning each router exchanges BGP routes with its adjacent routers.

Routing Information for 192.168.1.0/24

R1 and R4 import the static route 192.168.1.0/24 into BGP.

Since BGP prefers the shortest AS path, traffic to 192.168.1.0/24 will follow the shortest path to R1 or R4.

Route Analysis for Each Statement:

Statement A: R6 → R5 → R4 ✅ (Correct)

R6 does not have a direct route to 192.168.1.0/24, so it must rely on BGP advertisements from its EBGP neighbors.

R5 learns the route to 192.168.1.0/24 from R4.

Therefore, R6 forwards traffic to R5, and then R5 sends it to R4.

✅ Correct path: R6 → R5 → R4

Statement B: R5 → R4 ✅ (Correct)

R5 is directly connected to R4, and since R4 advertises the 192.168.1.0/24 route via BGP,

R5 will forward traffic directly to R4 as the shortest AS path.

✅ Correct path: R5 → R4

Statement C: R2 → R1 ✅ (Correct)

R2 is directly connected to R1 and learns the 192.168.1.0/24 route from R1 via BGP.

Since R1 advertises the static route, R2 forwards traffic directly to R1.

✅ Correct path: R2 → R1

Statement D: R3 → R2 → R1 ✅ (Correct)

R3 is directly connected to R2 and learns the 192.168.1.0/24 route from R2 via BGP.

Since R2 prefers R1 as the shortest AS path to 192.168.1.0/24,

R3 will send traffic to R2, and R2 will send it to R1.

✅ Correct path: R3 → R2 → R1

Final Conclusion:

✅ A. The path for traffic from R6 to 192.168.1.0/24 is R6 → R5 → R4.

✅ B. The path for traffic from R5 to 192.168.1.0/24 is R5 → R4.

✅ C. The path for traffic from R2 to 192.168.1.0/24 is R2 → R1.

✅ D. The path for traffic from R3 to 192.168.1.0/24 is R3 → R2 → R1.

Thus, the correct answers are: A, B, C, D.

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

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

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

Huawei port security provides protection actions to prevent unauthorized access and reduce the impact of MAC address security violations.

The port-security protect-action command supports three actions: protect, restrict, and shutdown.

The protect action silently discards packets associated with a security violation. It does not generate an alarm.

The restrict action also discards violating packets but additionally reports the security violation through a trap or alarm, allowing administrators to detect suspicious activity.

The shutdown action is the most disruptive protection mechanism. It places the affected interface into the error-down state and generates an alarm.

Static MAC address flapping occurs when a configured static MAC address unexpectedly appears on another interface, potentially indicating incorrect configuration or malicious network activity.

Choosing the appropriate protection action depends on security requirements and the operational consequences of disabling an interface.

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 Training Material.pdf

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The statement contains two material technical errors. The LSP Number field is one byte, or 8 bits, not 4 bits. An 8-bit field provides values from 0 through 255, allowing an IS-IS process to generate a maximum of 256 original LSP fragments for a system ID. Four bits would allow only 16 values and could not identify 256 fragments.

The statement also incorrectly says “a minimum of 256 LSP fragments.” The correct term is maximum: the process can generate up to 256 fragments under its normal system ID; it is not required to generate at least 256.

The final concept is correct: IS-IS LSP fragment extension permits additional system IDs to be configured. Each additional system ID provides space for another 256 extended LSP fragments, enabling the originating IS-IS process to advertise more link-state information.

Because a true/false statement must be correct in its entirety, the incorrect field length and “minimum” wording make the supplied statement false. The corrected version would state: “The LSP Number field is one byte long, allowing a maximum of 256 LSP fragments per system ID.” Huawei IS-IS LSP Fragment Extension

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the Network Setup

PC1 (192.168.1.1/24) and PC2 (192.168.1.2/24) are connected to SW1.

Both PCs are in the same VLAN, meaning communication should work without routing.

If there is a communication failure, it could be due to physical, VLAN, ARP, or port security issues.

2. Evaluating Each Answer Option

Option A: " SW1’s GE0/0/2 is shut down. "

Correct.

If GE0/0/2 is shut down, PC2 cannot send or receive traffic, causing communication failure.

Even if PC1 is working, PC2 will be unreachable.

✅ A is a valid cause.

Option B: " The link of SW1’s GE0/0/1 is faulty. "

Correct.

If GE0/0/1 has a faulty link, PC1 cannot communicate with PC2, causing failure.

Even if PC2 is working, PC1 will be unreachable.

✅ B is a valid cause.

Option C: " Incorrect static ARP entries are configured on the hosts. "

Correct.

If static ARP entries are incorrectly configured, PCs will map the wrong MAC addresses to IPs.

This will result in packet delivery failures, even if the physical network is working.

✅ C is a valid cause.

Option D: " Port isolation is configured on SW1. "

Correct.

Port isolation (or private VLAN) prevents direct communication between specific ports.

If port isolation is enabled on GE0/0/1 and GE0/0/2, PC1 and PC2 will be unable to reach each other.

✅ D is a valid cause.

Final Answer:

✅ A, B, C, and D are correct.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Troubleshooting VLAN and Layer 2 Communication Issues

Impact of Port Isolation and Private VLANs on Communication

Static ARP Entry Configuration and Its Effects on Network Connectivity

The display mpls lsp output on R1 contains the following entry for FEC 3.3.3.3/32:

In/Out Label: NULL/1025

Out Interface: GE0/0/1

NULL/1025 means R1 is the ingress LSR for this LSP. The packet initially has no label, so R1 performs a push operation and sends it toward R2 with label 1025.

R2’s corresponding entry is:

In/Out Label: 1025/3

Out Interface: GE0/0/1

Label value 3 is the MPLS implicit-null label. It is not placed in the outgoing packet. Instead, it instructs the penultimate-hop router—R2—to remove label 1025. This operation is called penultimate-hop popping (PHP). R2 consequently sends an unlabeled IPv4 packet to egress router R3, which processes the packet using normal IP forwarding.

Therefore, the packet sent from R1 carries label 1025, and R2 removes the label before forwarding it toward R3. Huawei MPLS label operations and PHP

In a hub-and-spoke VPN topology:

Spoke sites should be able to communicate only with the hub, not directly with each other.

This is achieved through RT (Route Target) control:

Spokes export routes with ERT = 200:1

Hub imports those routes with IRT = 200:1

Hub exports routes with ERT = 100:1

Spokes import those hub routes using IRT = 100:1

This results in:

Spokes receive hub routes, but

Spokes do not receive each other ' s routes, preventing direct spoke-to-spoke communication.

Official Huawei Extract:

" In a hub-spoke topology, spokes use one RT to export (e.g., 200:1), and the hub uses that as its import RT. The hub exports routes with a different RT (e.g., 100:1), and spokes import that RT. This enforces centralized traffic control through the hub. "

— [Huawei HCIA-Datacom Certification Guide – MPLS VPN and Route Target Control]

The statement is false due to a contradiction.

Sticky MAC addresses are not aged out automatically. Once a MAC address is converted to sticky, it is bound to the port and does not age out like dynamic MAC addresses unless manually cleared or the configuration is removed.

If the goal is to allow MAC entries to age out when users change frequently, dynamic MAC addresses (not sticky) should be used.

✅ Official Reference from Huawei:

" Sticky MAC addresses are retained across restarts and do not age out. To allow MAC addresses to time out and be relearned, do not use sticky configuration. "

— [Huawei HCIA-Datacom Certification Guide – Port Security Section]

Comprehensive and Detailed In-Depth Explanation:

To determine which routers are unable to import external routes, we need to analyze the behavior of each OSPF area type:

Stub Area (Area 1 - Contains R6)

Stub areas do not allow external routes (Type-5 LSAs).

Instead, the ABR (R2) generates a default route (0.0.0.0/0) for reachability outside the area.

R6 is in a stub area, so it cannot import external routes. ✅

Totally Stub Area (Area 2 - Contains R3, R4)

Totally stub areas block both external routes (Type-5 LSAs) and inter-area routes (Type-3 LSAs).

Only a default route (0.0.0.0/0) is injected by the ABR (R2).

R3 is in a totally stub area, so it cannot import external routes. ✅

R4, however, is just inside the totally stub area but is not restricted from generating external routes itself. ❌ (R4 can import external routes)

NSSA (Area 3 - Contains R5)

NSSAs allow external routes (Type-7 LSAs) but do not accept standard external routes (Type-5 LSAs) from other areas.

R5, being in an NSSA, can import external routes but only as Type-7 LSAs. ❌ (R5 can import external routes)

Final Answer: ✅ R3, R6 (Option A, C)

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the Hub-Spoke BGP Design

Hub-Spoke topology is commonly used in MPLS Layer 3 VPNs, where:

Hub-PE acts as a central router.

Spoke-PEs connect to the hub but do not communicate directly with each other.

eBGP (External BGP) is used between the Hub-PE and Spoke-PE routers.

2. The Role of AS Numbers in BGP Route Transmission

By default, BGP prevents routes from being sent back to the same AS (Autonomous System) to avoid loops (via the AS_PATH loop prevention mechanism).

However, in a Hub-Spoke MPLS VPN, the Hub-PE must be allowed to re-advertise routes learned from one spoke to another spoke.

This requires allowing repetitive AS numbers within the same AS to avoid BGP rejecting valid routes.

3. Solution: Using " Allow-AS Loop " on the Hub-PE

The allowas-in or allow-as-loop command must be used on Hub-PE to allow repetitive local AS numbers.

This ensures that routes from Spoke-PE1 (AS65002) are advertised to Spoke-PE2 (AS65003) via Hub-PE, even if AS numbers are repeated.

Example Configuration on Hub-PE:

plaintext

CopyEdit

bgp 65001

peer Spoke-PE1 allow-as-loop 2

peer Spoke-PE2 allow-as-loop 2

This allows Hub-PE to accept and propagate routes even if the AS number appears more than once.

4. Evaluating the Answer Choices

Option

Correct?

Reasoning

A. TRUE

✅ Correct

Hub-PE can be configured to allow repetitive AS numbers using the allow-as-loop feature.

B. FALSE

❌ Incorrect

BGP by default prevents repeated AS numbers, but this can be overridden.

✅ Correct Answer: A. TRUE

Final Conclusion:

By default, BGP prevents AS loopbacks.

Hub-PE needs to allow repetitive AS numbers for proper route transmission in the hub-spoke model.

The " allow-as-loop " command enables this functionality.

Thus, the correct answer is: TRUE.

The displayed BootLoader main menu assigns number 6 to the following option:

6. Password manager submenu

Therefore, the engineer must enter 6 at the Enter your choice (1–8): prompt to access the password-management functions. Inside that submenu, the engineer then selects the separate Clear the console login password option.

The distinction matters: entering 6 does not itself immediately clear the password; it opens the submenu containing the required recovery operation. The other choices perform unrelated functions:

5 opens the file-system submenu.

3 opens the Ethernet submenu.

4 opens the startup-parameters submenu.

Huawei’s documented console-password recovery procedure likewise instructs the administrator to restart the device, access the BootLoader main menu, and enter 6 to access the password manager submenu before selecting the console-password-clearing operation. Huawei console-login password recovery procedure.

1. Understanding Router-LSAs in OSPFv3

Router-LSA (Type 1 LSA) is generated by every OSPFv3 router to describe its own links and connected networks within the same area.

Each router in an OSPF area generates exactly one Router-LSA to advertise its own topology information.

Router-LSAs are flooded throughout the area but do not cross area boundaries.

2. Analyzing the Given OSPFv3 Network

The topology consists of three routers: R1, R2, and R3, all connected in OSPFv3 Area 0.

Since all three routers participate in OSPFv3, each router generates its own Router-LSA (Type 1 LSA).

R2, as an OSPF router, will have its own Router-LSA and also receive the Router-LSAs from R1 and R3.

3. Counting the Number of Router-LSAs in R2’s LSDB

R1 generates 1 Router-LSA (for itself).

R2 generates 1 Router-LSA (for itself).

R3 generates 1 Router-LSA (for itself).

Total Router-LSAs in R2’s LSDB = 3 (one from each router).

Final Answer:

Answer: 3

HCIP-Datacom-Advanced Routing & Switching Technology References:

OSPFv3 LSA Types and Their Roles

Understanding Router-LSA (Type 1) and Its Function in LSDB