Important Huawei H12-831_V1.0 Exam Questions

Answer: A, B, C, D

Explanation:

Comprehensive and Detailed In-Depth

Understanding the BGP Network Topology in the Questio n:

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 .

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 -- BGP Best Path Selection and AS Path Preferences

Huawei Official HCIP-Datacom Study Guide -- EBGP Route Advertisement and Static Route Import into BGP

Huawei Documentation on BGP Route Selection and Path Preference Mechanisms

Answer: A

Answer: B, C, D

Explanation:

Comprehensive and Detailed In-Depth

Understanding OSPF Areas and Route Propagation in the Network:

OSPF Area Types in the Questio n :

Area 0 (Backbone Area): Connects all areas and distributes routing information.

Area 1 (Standard Area): Regular OSPF area that can receive and forward external routes.

Area 2 (Totally NSSA - Totally Not-So-Stubby Area):

Does not allow external routes except for a default route injected by the ABR.

Area 3 (NSSA - Not-So-Stubby Area):

Allows external routes as Type 7 LSAs but does not accept Type 5 LSAs.

How External Routes Are Advertised in This Scenario:

R5 (in Area 3) imports 10.0.5.5/32 as an external route into OSPF.

Since Area 3 is an NSSA, the external route is advertised as a Type 7 LSA (not Type 5).

The ABR (R1) converts the Type 7 LSA into a Type 5 LSA and advertises it into Area 0.

Once in Area 0, this Type 5 LSA can be distributed to other areas except totally stubby or totally NSSA areas.

Route Distribution Analysis:

R5 (Area 3) R1 (Area 0, ABR):

R5 generates a Type 7 LSA for 10.0.5.5/32.

R1 (ABR) converts this Type 7 LSA into a Type 5 LSA and injects it into Area 0.

R2 (Area 0) R3 (Area 0):

Since Area 0 allows external Type 5 LSAs, R2 and R3 receive 10.0.5.5/32.

R2 and R3 have the route.

R6 (Area 1) Connected to Area 0:

Area 1 is a common area, meaning it can receive external Type 5 LSAs.

R6 has the route.

R4 (Area 2 - Totally NSSA):

Totally NSSA areas do NOT accept Type 5 or Type 7 LSAs.

Instead, they receive only a default route from the ABR (R3).

Since R4 does not receive external routes explicitly, it does NOT have 10.0.5.5/32.

R4 does NOT have the route.

Final Conclusion:

R2, R3, and R6 have the route 10.0.5.5/32.

R4 does not have the route because Area 2 is a Totally NSSA and only gets a default route.

Thus, the correct answer is:

R2, R3, and R6 have the route 10.0.5.5/32 in their routing tables.

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 -- OSPF Route Types and Area Behavior

Huawei Official HCIP-Datacom Study Guide -- OSPF LSA Types and Route Filtering in NSSA & Totally NSSA Areas

Huawei Documentation on Type 7 to Type 5 LSA Conversion in NSSA Areas

Answer: C

Explanation:

Comprehensive and Detailed In-Depth

Understanding OSPFv3 Areas and Routing Behavior

OSPFv3 Area Types in the Network:

Area 1 (Stub Area): Does not accept external LSAs (Type 5) but can receive Inter-Area-Prefix-LSAs (Type 3).

Area 2 (Common Area): Fully functional area that allows both Type 3 (Inter-Area) and Type 5 (External) LSAs.

Area 3 (NSSA - Not-So-Stubby Area): Does not accept Type 5 (External) LSAs but allows ASBRs to inject external routes using Type 7 LSAs, which are later converted to Type 5 in other areas.

Effect of stub no-summary Command on Area 1 (Configured on R2):

This command prevents Type 3 LSAs from entering Area 1, meaning R4 will not learn about 2000::6/128 from other areas.

R4 only has a default route (::/0) provided by R2 but not individual routes like 2000::6/128.

Route and Packet Flow Analysis

A . 'The LSDB of R4 contains the Inter-Area-Prefix-LSA that is generated by R1 and describes 2000::6/128.' (False)

R4 is in Area 1 (a totally stub area), which does not receive Type 3 LSAs.

Since 2000::6/128 is an external route from Area 2, it will not be present in R4's LSDB.

Thus, R4 does NOT have the Inter-Area-Prefix-LSA for 2000::6/128.

Statement A is incorrect.

B . 'The path for data packets from R4 to 2000::6 is R4 -> R1 -> R5 -> R3 -> R6.' (False)

R4 is in a totally stub area (Area 1), and it does not have a specific route for 2000::6/128.

It only has a default route (::/0) pointing to R2.

If R4 forwards traffic, it will send it to R2, NOT via R1, R5, and R3.

Statement B is incorrect.

C . 'The routing table of R4 does not contain the route 2000::6/128.' (True - Correct Answer)

R4 is in a totally stub area (Area 1), meaning it only receives a default route from R2 (::/0).

It does NOT receive specific routes like 2000::6/128.

Statement C is correct.

D . 'The path for data packets from R4 to 2000::6 is R4 -> R2 -> R6.' (False)

While R4 does forward all unknown traffic to R2 (due to the default route), R2 will NOT directly forward to R6.

R2 is an ABR (Area Border Router), and the actual path to 2000::6 must traverse Area 2, likely through other routers.

Statement D is incorrect.

Final Conclusion:

C. The routing table of R4 does not contain the route 2000::6/128.

Thus, the correct answer is: C. The routing table of R4 does not contain the route 2000::6/128.

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 -- OSPFv3 Area Types (Stub, NSSA, Common)

Huawei Official HCIP-Datacom Study Guide -- OSPFv3 LSAs and Routing Table Analysis

Huawei Documentation on Stub Area Behavior with stub no-summary Configuration

Answer: C, D

Explanation:

Comprehensive and Detailed In-Depth

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.