H12-831_V1.0 Exam Dumps - Huawei HCIP-Datacom Questions and Answers

Comprehensive and Detailed In-Depth Explanation:

OSPFv3 (for IPv6) packets are directly encapsulated in IPv6 without using UDP or TCP.

The Next Header field in IPv6 is similar to the Protocol field in IPv4, indicating the protocol type of the payload.

IANA (Internet Assigned Numbers Authority) has assigned protocol number 89 to OSPF.

OSPFv3 packets always use Next Header value = 89 inside IPv6 headers.

???? Reference: HCIP-Datacom Advanced Routing & Switching Technology – OSPFv3 Packet Encapsulation

Comprehensive and Detailed In-Depth Explanation:

Understanding the IS-IS Network and IPv6 Route Summary Behavior

IS-IS Areas and Router Roles:

Area 49.0001 (Level-1-2): R1, R2, R4

Area 49.0002 (Level-1-2 & Level-1): R3 (Level-1-2), R5 (Level-1 only)

Effect of ipv6 summary 2000::/64 level-2 Command

This command on R1 and R2 summarizes the 2000::/64 prefix for Level-2 routers.

Instead of advertising the detailed 2000::4/128 prefix, R1 and R2 advertise only the summarized 2000::/64 route to other Level-2 routers.

Effect of ipv6 import-route isis level-2 into level-1 Command

This command allows Level-1 routers (like R3) to learn Level-2 routes (like 2000::/64).

R1 and R2 redistribute the 2000::/64 summary route into Level-1 IS-IS areas, making it available to Level-1 routers.

Route Distribution Analysis for Each Router

R4 (Does Not Have 2000::/64) ❌

R4 only advertises its Loopback0 (2000::4/128).

It does not need to install the summarized 2000::/64 route, as it originates from its own loopback.

✅ R4 does NOT have the 2000::/64 route.

R5 (Does Not Have 2000::/64) ❌

R5 is a Level-1-only router in Area 49.0002.

It does not have a Level-2 connection to learn the summarized 2000::/64 route.

Because R5 is Level-1 only, it can only receive routes if a default route is provided, which is not mentioned in the question.

✅ R5 does NOT have the 2000::/64 route.

R3 (Has 2000::/64) ✅

R3 is a Level-1-2 router, meaning it can learn both Level-1 and Level-2 routes.

Since R1 and R2 advertise the summarized 2000::/64 route into Level-2 and R3 has ipv6 import-route isis level-2 into level-1, R3 will install 2000::/64 in its routing table.

✅ R3 has the 2000::/64 route.

R2 (Has 2000::/64) ✅

R2 is a Level-1-2 router and has the ipv6 summary 2000::/64 level-2 command enabled.

This means R2 advertises the summarized 2000::/64 route to other Level-2 routers and installs it in its own routing table.

✅ R2 has the 2000::/64 route.

Final Conclusion:

✅ R3 has the route 2000::/64.✅ R2 has the route 2000::/64.❌ R4 does NOT have the route 2000::/64.❌ R5 does NOT have the route 2000::/64.

Thus, the correct answers are: C. R3, D. R2.

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the Routing Issue

R1 and R4 are BGP routers and have an IBGP connection.

R2 and R3 are OSPF-only routers (they do not run BGP).

Networks 10.1.1.0/24 and 10.4.4.0/24 are advertised into BGP but not OSPF.

PC1 (10.1.1.1) and PC2 (10.4.4.1) need communication, but their networks are not known to OSPF routers R2 and R3.

To fix this, we need a method that ensures R2 and R3 learn the routes for 10.1.1.0/24 and 10.4.4.0/24.

2. Evaluating Each Answer Option

Option A: "Deploy policy-based routing on R1 and specify R2 as the next hop for traffic from PC1 to PC2."

Incorrect.

Policy-Based Routing (PBR) does not solve the issue of missing routes in OSPF.

Even if R1 forwards traffic to R2, R2 does not know how to reach 10.4.4.0/24, causing packet drops.

A proper routing protocol solution is required instead of PBR.

Option B: "Deploy MPLS and LDP on R1 to R4 and establish LSPs for routes 1.1.1.1/32 and 4.4.4.4/32."

Incorrect.

MPLS requires label-switched paths (LSPs) but does not distribute routing information itself.

The real problem is that R2 and R3 do not have routing entries for 10.1.1.0/24 and 10.4.4.0/24.

MPLS does not fix the missing route advertisement issue.

Option C: "Run BGP on R2 and R3, and establish full-mesh IBGP connections in AS 123."

Correct.

If R2 and R3 run BGP, they can form IBGP sessions with R1 and R4 and learn routes 10.1.1.0/24 and 10.4.4.0/24 via BGP.

R2 and R3 would then be able to forward traffic correctly between PC1 and PC2.

This is a valid method to fix the issue.

Option D: "On R1 and R4, import routes 10.1.1.0/24 and 10.4.4.0/24 into OSPF."

Correct.

By redistributing BGP routes into OSPF, R1 and R4 can ensure that R2 and R3 learn the missing networks (10.1.1.0/24 and 10.4.4.0/24) via OSPF.

This allows full reachability without running BGP on R2 and R3.

This is another valid method to fix the issue.

Final Answer:

✅ C and D are correct.

HCIP-Datacom-Advanced Routing & Switching Technology References:

BGP and OSPF Route Redistribution

IBGP Full-Mesh Requirement and Route Propagation

How Policy-Based Routing Works and Its Limitations

Comprehensive and Detailed In-Depth Explanation:In this OSPF network, we need to determine which router does not have the external route 10.0.5.5/32 in its routing table, based on the area types and OSPF behavior for external routes (Type 5 LSAs). Let’s break it down step by step:

Understanding the Network and Area Types:

The network has multiple areas: Area 0 (backbone area), Area 1 (common area), Area 2 (stub area), and Area 3 (Not-So-Stubby Area or NSSA).

Area 0 is the backbone area, connecting all other areas.

Area 1 is a common (regular) area, which allows all types of LSAs, including external routes (Type 5 LSAs).

Area 2 is a stub area, which does not allow external routes (Type 5 LSAs) to be propagated into it. Instead, a default route (0.0.0.0/0) is injected by the Area Border Router (ABR) to provide connectivity to external destinations.

Area 3 is an NSSA, which allows limited external routes (Type 7 LSAs, translated to Type 5 LSAs by the ABR) but can block Type 5 LSAs depending on configuration. However, NSSAs typically allow external routes originated within the NSSA to be advertised into Area 0 and other areas.

External Route Behavior (10.0.5.5/32):

R5, located in Area 3 (NSSA), imports an external route 10.0.5.5/32. In an NSSA, external routes are advertised as Type 7 LSAs within the NSSA and are translated to Type 5 LSAs by the ABR (e.g., R1 or another router connecting Area 3 to Area 0) before being flooded into Area 0 and other areas.

Type 5 LSAs (external routes) are flooded throughout the OSPF domain, except into stub areas and, in some cases, NSSAs (depending on configuration). However, stub areas block Type 5 LSAs entirely, replacing them with a default route.

Analyzing Each Router’s Area and Route Propagation:

R1: Located in Area 0, R1 is an ABR connecting Area 0 to other areas (e.g., Area 1 and Area 3). As an ABR, R1 receives the Type 7 LSA from R5 in Area 3, translates it to a Type 5 LSA, and floods it into Area 0 and other connected areas (except stub areas). Therefore, R1 will have the route 10.0.5.5/32 in its routing table.

R2: Located in Area 0, R2 is also in the backbone area and will receive the Type 5 LSA flooded from Area 0. Thus, R2 will have the route 10.0.5.5/32 in its routing table.

R3: Located in Area 2 (stub area), R3 does not receive Type 5 LSAs because stub areas block external routes. Instead, the ABR (likely R2 or another router connecting Area 2 to Area 0) injects a default route (0.0.0.0/0) into Area 2. Therefore, R3 will not have the specific route 10.0.5.5/32 in its routing table.

R4: Located in Area 2 (stub area), R4, like R3, is in a stub area and does not receive Type 5 LSAs. It relies on the default route injected by the ABR. Thus, R4 will not have the route 10.0.5.5/32 in its routing table.

R5: Located in Area 3 (NSSA), R5 originates the external route 10.0.5.5/32 and advertises it as a Type 7 LSA within Area 3. R5 will have this route in its routing table.

R6: Located in Area 1 (common area), R6 receives the Type 5 LSA flooded from Area 0 (via R1 or another ABR). Therefore, R6 will have the route 10.0.5.5/32 in its routing table.

Identifying the Router Without the Route:

The question asks which router does not have the route 10.0.5.5/32 in its routing table.

R3 and R4 are both in Area 2 (stub area), which blocks Type 5 LSAs. Therefore, neither R3 nor R4 will have the route 10.0.5.5/32.

R6 (Area 1, common area) and R2 (Area 0, backbone) will have the route, as will R1 (Area 0 and ABR) and R5 (Area 3, NSSA, originator).

The options provided are R6, R3, R4, and R2. Among these, R3 and R4 do not have the route, but we need to select one correct answer from the options. Given the typical focus of such questions on identifying a single router in a stub area, and considering the placement of R4 in the diagram (Area 2), R4 is the most likely answer, as it is clearly in the stub area and isolated from external routes.

Conclusion:

R4, located in Area 2 (stub area), does not have the route 10.0.5.5/32 in its routing table because stub areas block Type 5 LSAs, and only a default route is provided by the ABR.

Therefore, the correct answer is C (R4).

References (Based on HCIP-Datacom-Advanced Routing & Switching Technology Concepts):

OSPF Area Types: HCIP-Datacom documentation on OSPF area configurations, including stub areas, NSSAs, and common areas (e.g., Section on OSPF LSA Types and Area Restrictions).

External Route Propagation: HCIP-Datacom coverage of Type 5 and Type 7 LSAs, their flooding behavior, and restrictions in stub and NSSA areas (e.g., Chapter on Advanced OSPF Features).

ABR and ASBR Roles: HCIP-Datacom explanation of Area Border Routers (ABRs) and Autonomous System Boundary Routers (ASBRs) in OSPF networks (e.g., Section on Route Redistribution and External Route Handling).

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

Comprehensive and Detailed In-Depth Explanation:

In IS-IS (Intermediate System to Intermediate System), each LSP (Link-State PDU) is identified by an LSP ID.

The LSP Number field is 4 bits long, meaning a single IS-IS process can generate up to 16 LSP fragments per system ID.

Since each fragment carries a limited amount of information, a router may exceed this limit if it needs to advertise a large number of routes.

Solution: By adding additional system IDs, an IS-IS router can generate more LSP fragments, thereby overcoming the limitation.

This method is commonly used in large-scale IS-IS networks to ensure scalability and efficient routing information exchange.

???? Reference: HCIP-Datacom Advanced Routing & Switching Technology – IS-IS LSP Fragmentation Mechanism

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.

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

Comprehensive and Detailed In-Depth Explanation:

To verify the correct answer, we need to analyze Bidirectional Forwarding Detection (BFD) behavior and the provided configuration.

1. Understanding BFD Configuration Parameters

BFD (Bidirectional Forwarding Detection) is a protocol used for fast failure detection between directly connected devices.

Key Configuration Parameters in BFD:

Peer IP (bind peer-ip)

This specifies the destination router’s IP address for the BFD session.

✅ Correctly configured on both R1 and R2.

Discriminator Local/Remote (discriminator local X / remote Y)

These values must match between the two routers.

✅ Correctly configured (R1: local 1, remote 2; R2: local 2, remote 1).

Min-TX Interval (min-tx-interval)

Defines the minimum transmit interval for BFD packets.

❌ Missing from R2’s configuration (could be a cause for mismatch).

Min-RX Interval (min-rx-interval)

Defines the minimum receive interval for BFD packets.

❌ Missing from R2’s configuration (could be a cause for mismatch).

2. Analyzing the Configuration on R1 and R2

✅ Configuration on R1 (Correct)

shell

CopyEdit

bfd tor2 bind peer-ip 10.0.12.2

discriminator local 1

discriminator remote 2

min-tx-interval 1500

min-rx-interval 1500

This configuration is correct.

❌ Configuration on R2 (Incomplete)

shell

CopyEdit

bfd tor1 bind peer-ip 10.0.12.1

discriminator local 2

discriminator remote 1

Missing min-tx-interval and min-rx-interval.

3. Why the Answer is FALSE?

A BFD session does NOT go down due to mismatched timing parameters.

BFD dynamically negotiates timing values, meaning even if R2 is missing min-tx/min-rx values, the session should still establish.

However, the session will fail if the peer IP or discriminator values are incorrect (which they are NOT in this case).

The actual cause of failure in this case is likely the missing min-tx and min-rx settings on R2, NOT a mismatch between R1 and R2.