Huawei HCIP-Datacom-Advanced Routing & Switching Technology V1.0 H12-831_V1.0 Exam Questions

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Question 1

On the IS-IS IPv6 network shown in the figure, multi-topology is enabled on all routers.

The ipv6 default-route-advertise always level-1 command is configured in the IS-IS process of R4.

Which of the following routers does not have the default route in its routing table?

AR2

BR3

CR5

DR1

Answer : C

Comprehensive and Detailed In-Depth

Understanding the IS-IS Network Structure in the Questio n :

IS-IS Area IDs and Router Roles

Area 49.0001 (Level-1-2): Contains R1, R2, R4 (all Level-1-2 routers).

Area 49.0002 (Level-1-2 & Level-1): Contains R3 (Level-1-2) and R5 (Level-1 only).

Key Command Used: ipv6 default-route-advertise always level-1

This command forces R4 to advertise a default route (::/0) to all Level-1 routers within its area.

Only Level-1 routers in the same area as R4 will receive the default route.

Level-2 routers do not receive or propagate this default route unless additional configuration is done.

Route Distribution Analysis:

R4 (Level-1-2) is configured to advertise a default route to Level-1 routers.

R1 and R2 (both Level-1-2) are in the same area (49.0001) as R4, so they receive the default route.

R3 (Level-1-2) is in area 49.0002 but connects to R4 (49.0001), meaning it can receive the default route through its Level-1 connection.

R5 (Level-1 only) is in area 49.0002, but R4 does not propagate the default route to another Level-1 area (49.0002).

Since R5 is a Level-1 router and does not have a Level-2 connection, it cannot receive the default route from R4.

Final Conclusion:

R1 receives the default route.

R2 receives the default route.

R3 receives the default route.

R5 does NOT receive the default route.

Thus, the correct answer is: C. R5.

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 -- IS-IS Multi-Topology and IPv6 Routing

Huawei Official HCIP-Datacom Study Guide -- IS-IS Default Route Advertisement for Level-1 and Level-2 Areas

Huawei Documentation on ipv6 default-route-advertise always level-1 Command Behavior

Question 2

The figure shows the logical network architecture of a migration project. The purpose of the migration is to add network device R4 between R2 and R3.

OSPF runs between network devices.

After the physical network is connected, a network engineer incorrectly imports the backup configuration of R3 to R4 during the migration.

Given this, which of the following statements are true?

Options:

AThe OSPF neighbor relationship between R1 and R2 is not affected.

BAn OSPF neighbor relationship can be established between R2 and R4.

CAn OSPF neighbor relationship can be established between R3 and R4.

DAn OSPF neighbor relationship can be established between R1 and R3.

Answer : A, C

Comprehensive and Detailed In-Depth

1. Understanding OSPF Neighbor Relationships

OSPF (Open Shortest Path First) forms neighbor relationships based on these key conditions:

Routers must be in the same OSPF area.

The subnet mask and network type must match.

The Hello/Dead timers must match.

Authentication (if enabled) must match.

2. Analyzing the Given Scenario

R1 and R2 are in Area 0 (Backbone Area).

R3 and R4 are in Area 1 (Non-Backbone Area).

R4 was configured incorrectly using R3's backup configuration, which could cause issues.

3. Evaluating Each Answer Option

Option A: 'The OSPF neighbor relationship between R1 and R2 is not affected.'

Correct.

R1 and R2 are both in Area 0 and their configuration was not changed.

Since R4 was added only between R2 and R3, it does not impact R1 and R2.

A is correct.

Option B: 'An OSPF neighbor relationship can be established between R2 and R4.'

Incorrect.

R2 is in Area 0, but R4 is incorrectly configured using R3's backup, which likely placed it in Area 1.

OSPF neighbors cannot form across different areas unless an Area Border Router (ABR) is properly configured.

Since there is no indication of an ABR setup, the adjacency will fail.

B is incorrect.

Option C: 'An OSPF neighbor relationship can be established between R3 and R4.'

Correct.

R3 and R4 are both in Area 1, and R4's backup configuration comes from R3, meaning they likely have identical settings.

Since they share the same area and are directly connected, an OSPF adjacency is possible.

C is correct.

Option D: 'An OSPF neighbor relationship can be established between R1 and R3.'

Incorrect.

R1 is in Area 0, and R3 is in Area 1.

OSPF does not form neighbor relationships between different areas unless configured as an ABR, which is not mentioned.

D is incorrect.

Final Answer:

A and C are correct.

HCIP-Datacom-Advanced Routing & Switching Technology Reference:

OSPF Neighbor Formation and Area Design Principles

Troubleshooting OSPF Area Mismatches and Configuration Issues

OSPF Backbone Area (Area 0) and Inter-Area Communication

Question 3

On the network shown in the figure, the network administrator configures the DHCP snooping trust function on the switch.

GE0/0/2 is a trusted interface (connected to the DHCP Server).

GE0/0/3 is an untrusted interface (potential attacker).

Which of the following statements are true about the two interfaces?

Options:

AWhen receiving a DHCP response packet on GE0/0/2, the switch forwards the packet through GE0/0/1.

BWhen receiving a DHCP request packet on GE0/0/2, the switch forwards the packet through GE0/0/3.

CWhen receiving a DHCP response packet on GE0/0/3, the switch forwards the packet through GE0/0/1.

DWhen receiving a DHCP request packet on GE0/0/3, the switch forwards the packet through GE0/0/2.

Answer : A, D

Comprehensive and Detailed In-Depth

1. Understanding DHCP Snooping

DHCP Snooping is a security feature that filters untrusted DHCP messages to prevent attacks such as:

Rogue DHCP servers distributing incorrect IP addresses.

DHCP starvation attacks.

In DHCP Snooping, switch ports are classified as:

Trusted Interfaces: Allow both DHCP requests and DHCP responses to pass through.

Untrusted Interfaces: Allow only DHCP requests but drop DHCP responses (to prevent rogue DHCP servers).

2. Analyzing Each Answer Option

Option A: 'When receiving a DHCP response packet on GE0/0/2, the switch forwards the packet through GE0/0/1.'

Correct.

GE0/0/2 is a trusted interface (connected to the DHCP server).

DHCP responses (ACK, NAK, OFFER) come from the DHCP Server.

Since DHCP responses are allowed on trusted interfaces, the switch forwards them to the client (PC1) via GE0/0/1.

Option B: 'When receiving a DHCP request packet on GE0/0/2, the switch forwards the packet through GE0/0/3.'

Incorrect.

DHCP requests originate from clients (PC1, attackers, etc.), not from the DHCP server.

The DHCP request should be forwarded to the DHCP server via a trusted interface (not GE0/0/3, which is untrusted).

Option C: 'When receiving a DHCP response packet on GE0/0/3, the switch forwards the packet through GE0/0/1.'

Incorrect.

GE0/0/3 is an untrusted interface (connected to the attacker).

DHCP responses (ACK, OFFER) from untrusted interfaces are dropped to prevent rogue DHCP attacks.

The switch will not forward the packet.

Option D: 'When receiving a DHCP request packet on GE0/0/3, the switch forwards the packet through GE0/0/2.'

Correct.

DHCP requests originate from clients (PC1 or attacker).

Since DHCP requests are allowed on untrusted interfaces, the switch forwards them to the DHCP server via the trusted interface (GE0/0/2).

Final Answer:

A and D are correct.

HCIP-Datacom-Advanced Routing & Switching Technology Reference:

DHCP Snooping and Port Trust Classification

How Trusted and Untrusted Ports Handle DHCP Packets

Preventing Rogue DHCP Servers Using DHCP Snooping

Question 4

On the OSPFv3 network shown in the figure, area 1 is a stub area.

Which of the following LSAs is generated by only one router?

A. Inter-Area-Prefix-LSA B. Link-LSA C. Network-LSA D. Intra-Area-Prefix-LSA

AInter-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.

BLink-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.

CNetwork-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).

DIntra-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.

Answer : C

Comprehensive and Detailed In-Depth

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:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 -- OSPFv3 LSA Types and Multi-Area Behavior

Huawei Official HCIP-Datacom Study Guide -- OSPFv3 Stub Areas and LSA Advertisements

Huawei Documentation on OSPFv3 DR/BDR Roles and LSA Generation

Question 5

On the OSPF network shown in the figure, the cost values of links are marked, and OSPF IP FRR is enabled on R1. Which of the following statements is false?

AIf the link between R1 and SI is disconnected, Rl recalculates the optimal path to R3 and performs path switching instantly.

BIf the link between R2 and SI is disconnected, R1 recalculates the optimal path to R3 and performs path switching instantly.

CIf the link between R1 and SI is disconnected, R1 directly uses the backup path to forward packets to R3 because FRR is enabled on R1.

DIf the link between R1 and SI is disconnected and you check neighbor information on R1, the neighbor relationship between R1 and R2 will instantly display Down.

Answer : A

Question 6

The figure shows the Router-LSA generated by a router. Which of the following statements are true based on the LSA?

AThe router is an ASBR.

BAt least one interface on the router belongs to area 0.

CThe router is an ABR.

DAt least one interface on the router belongs to a stub area.

Answer : B, C

Question 7

On the OSPF network shown in the figure, area 1 is an NSSA, area 2 is a common area, and R4 imports an external route 10.0.4.4/32. The router ID of each router is 10.0.X.X, where X is the router number. If the asbr-summary 10.0.4.0 255.255.255.0 command is run in the OSPF processes of R1 and R3, which of the following routers have the route 10.0.4.0/24 in their routing tables?

AR1

BR2

CR3

DR5

Answer : A, C

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)

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

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