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

R4 is an ASBR inside Area 1, which is configured as a totally NSSA. When R4 imports 10.0.4.4/32, it originates a Type 7 NSSA LSA within Area 1. Therefore, option A is incorrect: a totally NSSA can contain Type 7 LSAs for external routes imported locally.

Type 7 LSAs have area-local flooding scope. R1 and R3, acting as NSSA ABRs, do not flood the original Type 7 LSA into Area 0 or Area 2. Instead, the selected translator converts the external information into a Type 5 LSA. The configured asbr-summary 10.0.4.0 255.255.255.0 command causes the translated external information to be advertised as the summarized 10.0.4.0/24 Type 5 LSA.

Area 2 is a common area and therefore cannot contain Type 7 LSAs. Option C is incorrect because Area 0 receives the translated Type 5 external LSA. Option D is not a valid conclusion because common and backbone areas support Type 4 LSAs, and asbr-summary does not suppress that LSA type. Huawei’s LSA support table explicitly identifies Type 7 as supported only in NSSA and totally NSSA areas. Huawei OSPF documentation

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the DIS (Designated Intermediate System) in IS-IS

In IS-IS, the DIS (Designated Intermediate System) is similar to the DR (Designated Router) in OSPF.

Unlike OSPF, IS-IS does not use an election based on priority; instead, the router with the highest priority becomes the DIS.

If there is a tie in priority, the router with the highest MAC address on the interface becomes the DIS.

The DIS is responsible for generating additional LSPs (pseudonode LSPs) for the link and synchronizing the database between routers.

2. How to Identify If the Router Is the DIS from the LSP

In the given LSP output, there are NO pseudonode LSPs (LSPs ending with .01).

The DIS is responsible for creating pseudonode LSPs, which represent a multi-access network in the IS-IS topology.

If the router were the DIS, it would generate both its own LSP (ending in .00) and a pseudonode LSP (ending in .01).

Since we only see an LSP ending in .00, this confirms that the router is NOT the DIS.

3. Evaluating the Answer Choices

Option A (TRUE) – Correct:

Since no pseudonode LSP is present, the router is not the DIS.

This confirms that the statement is TRUE.

Option B (FALSE) – Incorrect:

If the router were the DIS, it would generate pseudonode LSPs, but they are missing from the output.

Therefore, the statement is NOT false.

Final Answer:

Answer: A (TRUE)

HCIP-Datacom-Advanced Routing & Switching Technology References:

IS-IS Designated Intermediate System (DIS) Selection Process

Pseudonode LSP Generation in Multi-Access Networks

IS-IS LSP Structure and Identification of DIS

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the Network Topology

R1 and R2 are OSPF-enabled routers connected via the 10.0.12.0/24 subnet (Area 0).

PC1 (192.168.1.2/30) is connected to R1 via GE0/0/1.

PC2 (192.168.1.22/30) is connected to R2 via GE0/0/1.

OSPF ensures that R1 and R2 know about each other ' s directly connected networks.

2. Analyzing Connectivity

Can R1 ping 192.168.1.22 (PC2)?

Yes, if routing is properly configured.

OSPF ensures that R1 learns about 192.168.1.22 from R2.

Since R1 has a route to 192.168.1.22 via R2, it can ping PC2 successfully.

✅ Option A is correct.

Can R1 ping 192.168.1.21 (R2 ' s interface)?

Yes, since R1 and R2 are OSPF neighbors.

R1 learns 192.168.1.21 via OSPF and can reach it directly.

✅ Option B is correct.

Can R2 ping 192.168.1.2 (PC1)?

Yes, since OSPF ensures that R2 learns about 192.168.1.2 from R1.

Since R2 has a route to 192.168.1.2 via R1, it can ping PC1 successfully.

✅ Option C is correct.

Can PC1 and PC2 ping each other?

Yes, if default gateways and routing are configured correctly.

If R1 and R2 can ping each other and forward packets, PC1 and PC2 should be able to communicate.

❌ Option D is incorrect because PC1 and PC2 should be able to ping each other.

Final Answer:

✅ A, B, and C are correct.

HCIP-Datacom-Advanced Routing & Switching Technology References:

OSPF Inter-Router Communication and Route Advertisement

Default Gateway and Routing in Multi-Router Networks

Troubleshooting End-to-End Connectivity in Routed Networks

Comprehensive and Detailed In-Depth Explanation:

Understanding OSPFv3 LSA Types

OSPFv3 uses different LSA types than OSPFv2, with some being similar in function:

Link-LSA (Type 8): Generated by every router on a link to advertise link-local IPv6 information.

Intra-Area-Prefix-LSA (Type 9): Advertises IPv6 prefixes within an area.

Network-LSA (Type 2): Generated only by the Designated Router (DR) to advertise information about all routers on a multi-access network.

Inter-Area-Prefix-LSA (Type 3): Advertises network prefixes between OSPF areas (generated by ABRs).

Route Distribution Analysis:

A. Inter-Area-Prefix-LSA (Type 3) ❌ (Incorrect)

Generated by an ABR to advertise prefixes between OSPF areas.

More than one ABR can generate this LSA.

❌ Not always generated by only one router.

B. Link-LSA (Type 8) ❌ (Incorrect)

Each router generates its own Link-LSA for each link it participates in.

This means multiple routers can generate this LSA.

❌ Not generated by only one router.

C. Network-LSA (Type 2) ✅ (Correct)

Generated ONLY by the Designated Router (DR) on a multi-access network (such as an Ethernet link).

Other routers do not generate this LSA, only the DR does.

✅ Correct answer: This LSA is generated by only one router (the DR).

D. Intra-Area-Prefix-LSA (Type 9) ❌ (Incorrect)

Generated by any router to advertise IPv6 prefixes within an area.

Multiple routers in an area can generate this LSA.

❌ Not generated by only one router.

Final Conclusion:

✅ C. Network-LSA (Type 2) is the correct answer because it is generated by only one router—the Designated Router (DR).

Thus, the correct answer is: C. Network-LSA.

Yes, this is true. In OSPFv3:

Each router generates one Link-LSA per link.

The Link-LSA contains:

The router ' s link-local address

IPv6 prefixes associated with the interface

Options that are advertised to neighbors on the same link

It is not flooded throughout the OSPF area; it is only sent on the local link (similar to a Hello packet ' s behavior).

✅ Official Reference from Huawei:

" Each router sends a Link-LSA on every attached link. This LSA is not flooded beyond the link and includes link-local address, prefix list, and interface options. "

— [Huawei HCIA-Datacom OSPFv3 Chapter – LSA Types]

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.

Bidirectional Forwarding Detection (BFD) provides rapid connectivity-failure detection independently of BGP ' s normal Keepalive and Hold timers.

In this topology, R1 and R3 establish an IBGP relationship through loopback interfaces, with R2 providing intermediate connectivity through OSPF.

Disabling OSPF on R2 ' s GE0/0/1 interface disrupts the routing information required to maintain the end-to-end IBGP connection. Once BFD packets can no longer reach the peer, the BFD detection timer determines when the session failure is reported.

The configured detection interval is 1000 milliseconds, and the detection multiplier is 6.

Therefore, the detection period is:

\[ 1000\text{ ms}\times6=6000\text{ ms}=6\text{ s} \]

BFD can notify BGP of the failure without waiting for the normal BGP Hold timer to expire. The intended answer is D.

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Comprehensive and Detailed In-Depth Explanation:

To determine which statements are false, we need to understand how OSPFv3 and IS-IS work together, and how Inter-Area-Router LSAs (Type 3 LSAs) are generated in OSPF:

1. Understanding OSPF Inter-Area LSAs (Type 3)

OSPF generates Type 3 LSAs (Inter-Area-Prefix LSAs) to advertise networks between areas.

Only Area Border Routers (ABRs) generate Inter-Area LSAs.

Type 3 LSAs allow routes to be advertised from one OSPF area to another (e.g., from Area 0 to Area 1 or Area 2).

2. Analysis of Each Answer Option:

✅ A. " R3 generates an Inter-Area-Router-LSA in Area 0. " → TRUE

R3 is an ABR (connecting IS-IS and OSPF Area 0).

Since R3 is importing IS-IS routes into OSPFv3, it must generate Type 3 LSAs to advertise those routes in Area 0.

This statement is correct.

✅ B. " R2 generates an Inter-Area-Router-LSA in Area 0. " → TRUE

R2 is also an ABR (connecting IS-IS and OSPF Area 0).

Like R3, R2 imports IS-IS routes into OSPFv3 and advertises them into Area 0 using Type 3 LSAs.

This statement is correct.

❌ C. " R1 generates an Inter-Area-Router-LSA in Area 2. " → FALSE

R1 is not an ABR.

Only ABRs generate Type 3 LSAs, and R1 is not an ABR between Area 2 and Area 0.

This statement is false.

❌ D. " R2 generates an Inter-Area-Router-LSA in Area 1. " → FALSE

Area 1 is a stub area, and stub areas do not allow Inter-Area-Router LSAs (Type 3 LSAs) for external routes.

R2 does not generate Inter-Area LSAs in Area 1 because OSPF prevents this in stub areas.

This statement is false.

The ipv6 default-route-advertise always level-1 command instructs an IS-IS router to advertise an IPv6 default route, ::/0, unconditionally in its Level-1 routing domain.

In area 49.0001, R4 is a Level-1 router, while R1 and R2 are Level-1-2 routers. R4 advertises the default route through Level-1 LSPs, allowing R1 and R2 to learn it.

In area 49.0002, R5 is a Level-1 router and R3 is a Level-1-2 router. R5 similarly advertises a default route to R3.

The level-1 parameter limits the advertisements to their respective Level-1 areas. These advertisements are not automatically flooded throughout the Level-2 backbone.

R4 originates its own default-route advertisement rather than learning one from R1 or R2 in this scenario.

Therefore, R1, R2, and R3 have learned default routes.

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Comprehensive and Detailed In-Depth Explanation:

1. Understanding OSPFv3 and DR/BDR Election

In OSPFv3, on broadcast and non-broadcast networks, routers elect a Designated Router (DR) and a Backup Designated Router (BDR) to reduce LSA flooding.

The DR is responsible for generating Network LSAs (Type 2 LSAs) for the subnet.

The BDR takes over if the DR fails.

Other routers (DROther) only form adjacencies with the DR and BDR but still receive LSAs.

2. Understanding the LSA Output in the Figure

The LSA shown in the figure is a Type 1 (Router LSA).

The originating router is R2 (Router ID: 10.0.2.2).

The LSA lists two " Transit Network " links connected to R2.

The Neighbor Router IDs listed are 10.0.1.1 (R1) and 10.0.2.2 (R2).

3. Why the Statement is FALSE

A transit network (broadcast network) should have only ONE DR.

R1 and R2 both being DRs is incorrect, as only one DR per subnet should exist.

The presence of two " Transit Network " entries in the LSA suggests that there are two separate OSPF broadcast networks, each with its own DR.

This means R1 and R2 are each DRs on separate networks, but not both DRs on the same network.

Final Answer:

Answer: B (FALSE)

HCIP-Datacom-Advanced Routing & Switching Technology References:

OSPFv3 DR/BDR Election Process

OSPFv3 LSA Types and Their Roles

OSPFv3 Network Topology and LSA Interpretation

The AS_Path attribute records the autonomous systems through which a BGP route has passed. Huawei documentation describes it as a “private attribute of BGP,” meaning a BGP-specific route attribute. It is used for loop prevention, route selection and policy-based filtering.

The if-match as-path-filter command creates a route-policy matching condition based on an AS_Path filter. Because non-BGP routes do not carry the BGP AS_Path attribute, this matching clause applies only to BGP routes. Before configuring the matching clause, an AS_Path filter should be defined with the ip as-path-filter command. For example:

ip as-path-filter 2 permit _200_300

route-policy test permit node 10

if-match as-path-filter 2

This policy node matches BGP routes whose AS_Path satisfies the configured regular expression. Huawei’s “private attribute” wording should be understood as protocol-specific, not as saying that AS_PATH is an optional proprietary attribute; in standard BGP classification, AS_PATH is a well-known mandatory path attribute.

Huawei’s command reference explicitly states that if-match as-path-filter is applicable only to BGP routes. Huawei if-match as-path-filter reference

Comprehensive and Detailed In-Depth Explanation:

Understanding the BGP Network Topology in the Question:

BGP Peering & Route Distribution

Each router forms EBGP peer relationships with directly connected neighbors.

R1 and R4 import the static route 192.168.1.0/24 into BGP and advertise it to their peers.

Community attributes are attached to routes to influence routing policies.

Effect of Community Attribute 1:1

R1 marks 192.168.1.0/24 with community 1:1 before advertising it.

R3 has a policy that rejects any routes with community attribute 1:1.

Since R1’s advertisement contains 1:1, R3 will not accept 192.168.1.0/24 from R2.

Route Selection and Traffic Flow Analysis:

R1 advertises 192.168.1.0/24 with community 1:1 to R2.

R3 rejects this route from R2 because of the configured routing policy.

R4 also advertises 192.168.1.0/24 to its EBGP neighbors without community 1:1.

R5 learns the route from R4 and advertises it to R3.

Since R5’s advertisement does not include community 1:1, R3 accepts the route from R5.

Thus, the best available path for R3 to reach 192.168.1.0/24 is R3 → R5 → R1.

✅ Correct Path: R3 → R5 → R1

Checking Each Option:

❌ Option A: R3 → R2 → R4 (Incorrect)

R3 does not learn the route from R2 because it rejects community 1:1.

Since R1 added 1:1, and R2 propagated the same community, R3 will not accept this path.

❌ Option B: R3 does not have a route to 192.168.1.0/24 (Incorrect)

R3 does have a route, but it learns it from R5 instead of R2.

❌ Option C: R3 → R2 → R1 (Incorrect)

R1 marked the route with 1:1, and R2 advertised it with the same community.

Since R3 rejects 1:1 routes, it will not use this path.

✅ Option D: R3 → R5 → R1 (Correct)

R5 learns the route from R4, which does not have community 1:1, and advertises it to R3.

R3 accepts this route and forwards traffic to R5, which sends it to R1.

Final Conclusion:

✅ D. The correct path for traffic from R3 to 192.168.1.0/24 is R3 → R5 → R1.

Thus, the correct answer is: D.