H12-831_V1.0 HCIP-Datacom-Advanced Routing & Switching Technology V1.0 Questions and Answers

Comprehensive and Detailed In-Depth Explanation:

To determine the correct answer, we need to analyze how each command impacts OSPF neighbor relationships.

1. Understanding OSPF Neighbor Formation

OSPF routers form neighbor relationships when they meet the following conditions:

They are in the same subnet (IP addresses and subnet masks must match).

They are in the same OSPF area.

They use the same network type (e.g., Broadcast, Point-to-Point).

Authentication (if configured) must match.

Hello and Dead timers must match.

2. Analyzing Each Answer Option

❌ A. "undo ip address 10.0.12.2 24" → Affects OSPF Neighbor Status

Removing the IP address will prevent the interface from sending and receiving OSPF Hello packets.

Without an IP address, OSPF cannot establish neighbor relationships.

Effect: Breaks OSPF neighbor status.

✅ B. "undo description" → Does NOT Affect OSPF Neighbor Status

The interface description is just a label for administrators and has no impact on OSPF functionality.

It does not affect neighbor relationships, routing, or communication.

Effect: No impact on OSPF neighbors.

❌ C. "undo ospf cost" → Affects OSPF Neighbor Status Indirectly

OSPF cost determines the path selection but does NOT break the neighbor relationship.

However, if the cost change leads to routing table recalculations, it might cause temporary convergence issues.

Effect: Does not directly break neighbor status, but affects route selection.

❌ D. "undo ospf dr-priority" → Affects OSPF Neighbor Status (Possibly Causes DR Re-Election)

OSPF DR/BDR election uses priority values.

If changed, a new election might occur, leading to a temporary loss of neighbor relationships.

Effect: Might cause OSPF neighbor reset (temporary impact on adjacency).

Comprehensive and Detailed In-Depth Explanation:

To determine the correct answers, we need to analyze OSPFv3 behavior and Inter-Area-Prefix LSAs (Type 3 LSAs).

1. Understanding OSPFv3 Inter-Area-Prefix LSAs (Type 3 LSAs)

Type 3 LSAs (Inter-Area-Prefix LSAs) are generated by an ABR (Area Border Router) to advertise networks between areas.

If a router in one area learns a prefix from another area, it generates a Type 3 LSA to advertise it further.

Stub areas (Area 1) do not allow external LSAs, including Type 3 LSAs for external routes.

NSSA areas (Area 3) accept external routes but redistribute them as Type 7 LSAs before being converted to Type 5 LSAs by an NSSA ABR.

2. Analyzing Each Answer Option:

✅ A. "The Inter-Area-Prefix-LSA that is generated by R1 and describes 2000::6/128 exists in Area 0." → TRUE

R6 has 2000::6/128 in Area 2.

R2 is the ABR that brings this prefix into Area 0 as a Type 3 LSA.

R1, being in Area 0, learns this LSA from R2.

Thus, this statement is correct.

❌ B. "The Inter-Area-Prefix-LSA that is generated by R1 and describes 2000::6/128 exists in Area 3." → FALSE

R1 is not an ABR for Area 3, so it does not generate an LSA for 2000::6/128 in Area 3.

Instead, R3 (the ABR between Area 0 and Area 3) would be responsible for propagating routes.

This statement is false.

❌ C. "The Inter-Area-Prefix-LSA that is generated by R2 and describes 2000::6/128 exists in Area 1." → FALSE

Area 1 is a stub area and does not accept external LSAs (including Type 3 LSAs from other areas).

R2 cannot generate and send a Type 3 LSA for 2000::6/128 into Area 1.

This statement is false.

✅ D. "The Inter-Area-Prefix-LSA that is generated by R3 and describes 2000::6/128 exists in Area 2." → TRUE

R3 is an ABR and learns 2000::6/128 from R2 (which originally learned it from R6 in Area 2).

Since Area 2 is a normal (non-stub, non-NSSA) area, Type 3 LSAs are allowed.

R3 generates and advertises this Inter-Area-Prefix-LSA for 2000::6/128 into Area 2.

Thus, this statement is correct.

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:

Step 1: Analyzing the Primary Path

The given network uses IS-IS Auto FRR, which ensures a backup route in case of failure.

The shortest path from R1 to 10.0.3.3/32 is calculated based on the OSPF link costs:

Path 1 (Primary Path): R1 → R2 → R3

Cost: 10 (R1→R2) + 5 (R2→R3) = 15 ✅

Step 2: Checking the Backup Path

The statement claims that the backup path is R1 → R4 → R2 → R3. Let's calculate the cost:

Path 2 (Backup Path via R4): R1 → R4 → R2 → R3

Cost: 10 (R1→R4) + 50 (R4→R2) + 5 (R2→R3) = 65 ❌ (Too high)

The backup path should be an alternative shortest path that is as close as possible to the primary path in cost.

R1 → R4 → R2 → R3 is not a feasible backup path because the cost (65) is significantly higher than the primary path (15).

Step 3: Correct Backup Path Selection

If IS-IS Auto FRR is enabled, a feasible backup path should have a cost close to the primary path.

In this scenario, no viable alternative path meets the Auto FRR requirements efficiently.

The given backup path is incorrect.

Final Answer: ✅ FALSE (Option B)

References:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 – IS-IS Auto FRR Mechanism

OSPF Route Selection and Fast Reroute Principles

OSPF and IS-IS Path Cost Calculation

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:

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:

To determine the correct matches, we need to analyze VLAN aggregation and MUX VLAN behavior in the given topology.

1. Understanding VLAN Aggregation and MUX VLAN Roles

VLAN Aggregation:

Sub-VLANs (e.g., VLAN 10) are part of a Super-VLAN (e.g., VLAN 100) and share a common gateway.

Hosts in the same Sub-VLAN can communicate directly.

MUX VLAN (Multiple User Group VLAN):

Principal VLAN (VLAN 30): Includes servers, accessible by all VLAN types.

Separate VLAN (VLAN 20): Cannot communicate with other Separate VLAN hosts, but can communicate with the Principal VLAN (Server).

Group VLAN (VLAN 10 - Sub-VLANs): Hosts within the same Group VLAN can communicate, and they can also access the Principal VLAN (Server).

2. Analyzing the Connectivity

PC1 (Sub-VLAN 10 - Employee VLAN)

Can communicate with PC2 (same Sub-VLAN).

Can communicate with the Server (VLAN 30 - Principal VLAN).

PC2 (Sub-VLAN 10 - Employee VLAN)

Can communicate with PC1 (same Sub-VLAN).

Can communicate with the Server (VLAN 30 - Principal VLAN).

PC3 (VLAN 20 - Separate VLAN - Guest VLAN)

Cannot communicate with other PCs in Employee VLAN (PC1, PC2) or Guest VLAN (PC4).

Can communicate with the Server (VLAN 30 - Principal VLAN).

PC4 (VLAN 20 - Separate VLAN - Guest VLAN)

Cannot communicate with other PCs in Employee VLAN (PC1, PC2) or Guest VLAN (PC3).

Can communicate with the Server (VLAN 30 - Principal VLAN).

Server (VLAN 30 - Principal VLAN)

Can communicate with all PCs (PC1, PC2, PC3, PC4) because it belongs to the Principal VLAN, which serves all VLANs.

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-1-2 Command on R4

Route summarization in IS-IS allows an L1-L2 router (R4) to aggregate IPv6 prefixes and advertise a summary route (2000::/64) into both Level-1 and Level-2 areas.

This means R4 will advertise only 2000::/64 instead of specific /128 routes (like 2000::4/128).

All Level-1 and Level-2 routers connected to R4 will receive the summary route 2000::/64 instead of the detailed /128 routes.

Route Distribution Analysis for Each Statement

A. The routing table of R1 contains the route 2000::4/128. ✅ (True)

R1 is a Level-1-2 router in the same area (49.0001) as R4, so it receives both the summarized 2000::/64 route and the more specific 2000::4/128 route.

Since R1 is directly connected to R4, it can still learn the 2000::4/128 route.

✅ Statement A is true.

B. The routing table of R3 contains the route 2000::/64. ✅ (True)

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

Since R4 (a Level-1-2 router) advertises the summarized 2000::/64 route into both levels, R3 will receive 2000::/64 in its routing table.

✅ Statement B is true.

C. The routing table of R2 contains the route 2000::/64. ✅ (True)

R2 is a Level-1-2 router in the same area as R4, meaning it receives the summarized 2000::/64 route.

This is expected behavior since R4 advertises the summary route into both Level-1 and Level-2 areas.

✅ Statement C is true.

D. The routing table of R5 does not contain the route 2000::/64. ❌ (False - Correct Answer)

R5 is a Level-1 router, meaning it can only receive Level-1 routes unless a default route is provided.

Since R3 (a Level-1-2 router) learns 2000::/64, it can propagate it into the Level-1 area (49.0002).

This means R5 will receive the summary route 2000::/64 from R3.

Thus, R5 does contain 2000::/64, making this statement false.

❌ Statement D is false (correct answer).

Final Conclusion:

✅ A. The routing table of R1 contains the route 2000::4/128. (True)✅ B. The routing table of R3 contains the route 2000::/64. (True)✅ C. The routing table of R2 contains the route 2000::/64. (True)❌ D. The routing table of R5 does not contain the route 2000::/64. (False - Correct Answer)

Thus, the correct answer is: D. The routing table of R5 does not contain the route 2000::/64 (False Statement).

Comprehensive and Detailed In-Depth Explanation:

MPLS packet forwarding is based on label information stored in the LFIB (Label Forwarding Information Base).

The role of different tables in MPLS:✅ RIB (Routing Information Base): Stores routing information, but does not handle MPLS label forwarding.✅ LIB (Label Information Base): Stores label bindings but is used for control-plane operations.✅ FIB (Forwarding Information Base): Used for IP forwarding, not MPLS forwarding.✅ LFIB (Label Forwarding Information Base): The correct table, which maps incoming labels to outgoing labels (or actions like swap, push, pop) and is used for actual MPLS packet forwarding.

???? Reference: HCIP-Datacom Advanced Routing & Switching Technology – MPLS LFIB and Label Forwarding

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)

References:

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

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

Comprehensive and Detailed In-Depth Explanation:

Understanding the BGP and IS-IS Network Topology in the Question:

IS-IS Areas:

Area 49.0001 (Level-1 IS-IS): R1, R2, R4, R5.

Area 49.0002 (Level-2 IS-IS): R3, R6.

R2 acts as an ABR (Area Border Router) and redistributes routes between Level-1 and Level-2 using import-route isis level-2 into level-1.

BGP Route Reflection & Peering:

R2 and R5 are Route Reflectors (RRs).

iBGP peering is established among all routers (R1, R2, R3, R4, R5, R6).

R1 and R4 import 192.168.1.0/24 into BGP, meaning this prefix will be advertised to all iBGP peers.

R3 and R6 import 192.168.2.0/24 into BGP, meaning this prefix will also be advertised to all iBGP peers.

Route Distribution Analysis:

Route to 192.168.1.0/24 (Imported by R1 & R4):

R1 and R4 advertise 192.168.1.0/24 into iBGP.

Since R2 and R5 are Route Reflectors (RRs), they will reflect these routes to all their iBGP clients (R1, R3, R4, R6).

R2 learns two valid routes to 192.168.1.0/24 (from R1 and R4).

R5, as another RR, learns both routes and advertises them as well.

R2 ultimately has three valid paths (direct from R1 and R4, plus a reflected route from R5).✅ Statement C is correct: The BGP routing table of R2 contains three valid routes to 192.168.1.0/24.

R5 also learns 192.168.1.0/24 from both R1 and R4.✅ Statement B is correct: The BGP routing table of R5 contains two valid routes to 192.168.1.0/24 (from R1 and R4).

Route to 192.168.2.0/24 (Imported by R3 & R6):

R3 and R6 import 192.168.2.0/24 into BGP.

R2 and R5 (Route Reflectors) learn this route and reflect it to their clients (R1, R3, R4, R6).

R4 receives three valid paths (directly from R3 and R6 via BGP, and one additional reflected path via R5).✅ Statement D is correct: The BGP routing table of R4 contains three valid routes to 192.168.2.0/24.

Checking Statement A:

R3 originally imports 192.168.2.0/24 and advertises it.

Since it is a Route Reflector Client of R5 and R2, it should have multiple routes via iBGP, not just one.❌ Statement A is incorrect because R3 should have multiple valid routes, not just one.

Final Conclusion:

✅ B. The BGP routing table of R5 contains two valid routes to 192.168.1.0/24.✅ C. The BGP routing table of R2 contains three valid routes to 192.168.1.0/24.✅ D. The BGP routing table of R4 contains three valid routes to 192.168.2.0/24.❌ A. The BGP routing table of R3 does NOT contain only one valid route to 192.168.2.0/24 (it has multiple routes).

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

 Network cable → Use a tester to check connectivity.

 Device version file → Check the size of the software package and check whether the file matches the device model.

 Board → Install the board on a device that is not connected to the network and observe the running status of the device.

 License → Check whether the license is in the validity period to prevent device functions from being affected.

 Migration personnel list → Check whether responsibilities and permissions are clearly assigned.

Comprehensive and Detailed In-Depth Explanation:

1. Network Cable - Connectivity Testing:

Before starting a migration project, all network cables should be tested for physical connectivity issues.

Network testers can be used to detect any breaks, shorts, or incorrect wiring.

Ensuring proper connectivity avoids delays and troubleshooting issues during the migration.

2. Device Version File - Software Compatibility Check:

Firmware and software versions must be verified before upgrading or migrating network devices.

The device version file should match the model and hardware specifications to avoid compatibility issues.

If incorrect software is used, the device may not function properly or could become inoperable.

3. Board - Installation and Hardware Verification:

Before installing new hardware modules (boards, line cards, etc.) into a production environment, they should be tested in isolation.

Testing ensures the board is operational and does not introduce faults into the system.

If a board is faulty, it can cause device failure or unexpected behavior in the migration.

4. License - Validity and Activation Check:

Some network devices require licenses for full functionality (e.g., advanced routing, security features).

If a license is expired or missing, critical functions may be disabled after migration.

Checking license status in advance prevents unexpected downtime or service disruptions.

5. Migration Personnel List - Roles and Responsibilities Assignment:

Large network migrations require clear responsibility assignments for each team member.

A migration personnel list ensures that everyone knows their role, tasks, and permissions.

Proper coordination avoids miscommunication, errors, and project delays.

Key Takeaways:

✅ Network cables should be tested for connectivity.✅ Software versions should match the hardware model to prevent incompatibility.✅ Hardware boards should be tested before installing into production.✅ Licenses should be verified to prevent service disruptions.✅ Migration personnel roles should be clearly defined for smooth execution.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Huawei HCIP-Datacom Official Certification Guide, Chapter on Network Migration Best Practices.

Huawei Enterprise Networking Whitepapers, Guidelines on Software & Hardware Pre-checks for Migration.

Huawei Technical Documentation, License Management in Huawei Datacom Devices.

Comprehensive and Detailed In-Depth Explanation:

To verify the correct answer, let's analyze the LSA types in OSPFv3 and how they work in the given topology.

1. Understanding OSPFv3 LSAs in the Figure

From the command output shown in the image:

LS Type: Intra-Area-Prefix-LSA (Type 9 in OSPFv3).

Originating Router: 10.0.2.2 (R2).

Referenced LS Type: 0x2002, which corresponds to a Network-LSA (Type 2).

Prefix Advertised: 2000:23::/64, which is an IPv6 prefix associated with a network segment.

2. What is an Intra-Area-Prefix LSA (Type 9) in OSPFv3?

In OSPFv3, Type 9 LSAs (Intra-Area-Prefix LSAs) describe IPv6 prefixes associated with either Router-LSAs (Type 1) or Network-LSAs (Type 2).

In multi-access networks (e.g., Ethernet), the DR (Designated Router) generates a Network-LSA (Type 2), which represents the shared network segment.

R2 is likely the DR in this topology, meaning it generates a Network-LSA (Type 2) and an associated Intra-Area-Prefix LSA (Type 9) for the subnet.

3. Analyzing Why the Statement is TRUE

R2 (10.0.2.2) is the originator of the Intra-Area-Prefix LSA (Type 9).

The LSA references a Network-LSA (Type 2), confirming that R2 is the DR for the subnet.

This means the LSA is correctly describing the IPv6 prefix associated with the network.

Since the LSA is visible in R3's LSDB, R3 is learning this information from R2.

All these points confirm that the statement is TRUE.

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.

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).

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.

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 the Spanning Tree Protocol (STP) and Root Bridge Selection

Spanning Tree Protocol (STP) is used to prevent loops in a Layer 2 network by electing a Root Bridge and determining a loop-free topology.

The Root Bridge is elected based on the lowest Bridge ID (BID), which consists of:

Priority Value (Lower is preferred, default is 32768).

MAC Address (Lower MAC wins in case of a tie).

The optimal forwarding path is chosen based on cost, which is usually determined by the link bandwidth.

Why the Path is Not Optimal?

The network engineer states that all links have the same cost, meaning that the STP Root Bridge election determines the topology rather than cost differences.

The fact that the path between PC1 and PC2 is suboptimal suggests that the Root Bridge may not be ideally placed.

Determining the Likely Root Bridge:

The Root Bridge is the switch with the lowest BID (priority + MAC).

All switches calculate the shortest path to the Root Bridge and place ports in either Forwarding or Blocking mode.

From the diagram, the traffic is flowing through SW2 → SW4 → SW3 instead of directly via SW2 → SW3.

This suggests that the Root Bridge is likely SW1 or SW4 because:

Root Bridges do not block any ports.

If SW1 or SW4 is the Root Bridge, the spanning tree topology might force the path to take a longer route.

Key Takeaways:

Root Bridge selection influences the entire Layer 2 forwarding path.

The lowest Bridge ID (priority + MAC) determines the Root Bridge.

If a suboptimal path is taken, the Root Bridge is likely placed in a location that forces certain links to block.

In this scenario, SW1 or SW4 is the most probable Root Bridge, forcing traffic through an unintended path.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Huawei HCIP-Datacom Official Certification Guide, Chapter on Spanning Tree Protocol (STP) and Root Bridge Selection.

Huawei Datacom Training Materials, Section on STP Convergence and Network Optimization.

Huawei Datacom Configuration Guide, Command Reference for STP Root Bridge Selection and Path Calculation.

Comprehensive and Detailed In-Depth Explanation:

The Link Layer Discovery Protocol (LLDP) is used for discovering neighboring devices. The given LLDP output contains key details about the neighboring device (R2), including its system name, interface, and management IP address. Let's analyze each option carefully:

Option A: "The sysname of the peer device is R2." ✅ Correct

The output clearly shows System name: R2, which confirms that the neighbor's system name is indeed R2.

Option B: "The interface number of the peer device is GE0/0/0." ✅ Correct

The Port ID in the LLDP output is GE0/0/0, which matches the statement in Option B.

Option C: "The VLAN ID of the peer device is 1." ❌ Incorrect

The given LLDP output does not mention any VLAN ID information. Therefore, this option is false.

Option D: "The management IP address of the peer device is 192.168.1.1." ✅ Correct

The Management address field in the LLDP output confirms the IP address as 192.168.1.1, making this statement true.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Huawei HCIP-Datacom Official Certification Guide, Chapter on LLDP and Network Device Discovery.

HCIA/HCIP Datacom Training Materials – LLDP Neighbor Discovery Commands.

Huawei Datacom Configuration Guide – Section on display lldp neighbor interface.

Comprehensive and Detailed In-Depth Explanation:

Understanding the LSA Table in the Figure

The LSDB (Link-State Database) of R4 displays an Intra-Area-Prefix-LSA for Area 0.0.0.1. The table contains:

Three LSAs originating from R4 (10.0.4.4)

Prefixes referencing both Router-LSAs and Network-LSAs

Different Sequence Numbers and Checksums, indicating multiple link-state changes

OSPFv3 LSA Types Relevant to the Question

Router-LSA (Type 1)

Generated by every router to describe its links within an area.

Network-LSA (Type 2)

Generated only by the Designated Router (DR) for multi-access networks (such as Ethernet).

Advertises all routers connected to the same segment.

Intra-Area-Prefix-LSA (Type 9)

Advertises IPv6 prefixes associated with a Router-LSA (Type 1) or Network-LSA (Type 2).

Analysis of Each Statement

A. The three LSAs belong to area 1. ✅ (True)

The table explicitly shows "Intra-Area-Prefix-LSA (Area 0.0.0.1)", meaning all LSAs are for Area 1.

The Link State IDs also indicate intra-area advertisements.

✅ Statement A is correct.

B. Area 1 is a stub area. ❌ (False)

There is no indication that Area 1 is a stub area.

Stub areas do not receive Type 5 (External) LSAs, and the LSDB does not show Type 3 (Inter-Area) LSAs either.

Network-LSAs (Type 2) are not typically seen in stub areas unless explicitly configured.

❌ Statement B is incorrect.

C. No OSPFv3 neighbor relationship is established on at least one link of R4. ✅ (True)

One LSA references a Router-LSA, while two reference Network-LSAs.

A Router-LSA alone suggests that R4 has at least one point-to-point or unnumbered link with no OSPFv3 adjacency.

This means R4 has an interface with no neighbor (e.g., a passive interface or down link).

✅ Statement C is correct.

D. R4 is the DR on a link. ✅ (True)

The presence of Network-LSAs (Type 2) indicates that a multi-access link exists.

Since R4 is the origin of the Network-LSA, it must be the DR (Designated Router) for that link.

✅ Statement D is correct.

Final Conclusion:

✅ A. The three LSAs belong to area 1. (True)❌ B. Area 1 is a stub area. (False)✅ C. No OSPFv3 neighbor relationship is established on at least one link of R4. (True)✅ D. R4 is the DR on a link. (True)

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

Comprehensive and Detailed In-Depth Explanation:

Key OSPF Concepts to Consider:

Area 1 is an NSSA (Not-So-Stubby Area):

NSSAs allow external routes but advertise them as Type-7 LSAs.

The ABR (R2) converts these Type-7 LSAs into Type-5 LSAs for the backbone (Area 0).

Area 2 is a Stub Area:

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

This means that R5 (inside Area 2) will NOT receive external routes like 10.0.4.4/32 or 10.0.4.0/24.

Effect of asbr-summary 10.0.4.0 255.255.255.0 on R1 and R3:

This command ensures that R1 and R3 will see a summarized route 10.0.4.0/24 instead of specific /32 routes.

Routing Table Analysis:

R1 (ABR for NSSA, with ASBR summary configured)

Connected to Area 1 (NSSA) and Area 0 (Backbone)

Since asbr-summary 10.0.4.0 255.255.255.0 is configured on R1, it contains both 10.0.4.4/32 (from R4) and the summarized 10.0.4.0/24.

✅ Matches Option 4: The routing table contains both 10.0.4.4/32 and 10.0.4.0/24.

R5 (Inside Area 2 - Stub Area)

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

Since R5 is inside a stub area, it does not contain 10.0.4.4/32 or 10.0.4.0/24.

✅ Matches Option 3: The routing table does not contain 10.0.4.4/32 or 10.0.4.0/24.

R2 (ABR between NSSA and Backbone, but no ASBR summary configured)

R2 converts Type-7 LSAs from R4 into Type-5 LSAs and advertises them into Area 0.

Since no ASBR summary is configured on R2, it only sees the specific external route 10.0.4.4/32 but not the summarized 10.0.4.0/24.

✅ Matches Option 1: The routing table contains 10.0.4.4/32 only.

R3 (Another ABR with ASBR summary configured)

R3 has asbr-summary 10.0.4.0 255.255.255.0 configured, which means it will summarize the external routes.

Instead of 10.0.4.4/32, R3 will only have the summarized 10.0.4.0/24 route.

✅ Matches Option 2: The routing table contains 10.0.4.0/24 only.

References:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 – OSPF Areas (Stub, NSSA, and Backbone)

OSPF External Route Advertisement and Summarization

OSPF NSSA Behavior and Type-7 to Type-5 Conversion

Comprehensive and Detailed In-Depth Explanation:

To analyze the correct answer, we need to break down the topology and protocol behaviors step by step:

Understanding the IS-IS and OSPFv3 Network Setup:

IS-IS IPv6 is running between R2, R6, and R3.

OSPFv3 is running on other links.

Area 1 is a stub area, which means it does not accept external routes but can have a default route (::/0).

Area 2 is an NSSA (Not-So-Stubby Area), meaning it allows external routes as NSSA external LSAs.

Analysis of Each Answer Option:

A. "The routing table of R6 contains the route ::/0." → FALSE

R6 only participates in IS-IS (Level-1) and does not receive a default route (::/0) from Level-2 routers.

Since R6 is in IS-IS Level-1 and does not have a connection to a Level-2 router that provides a default route, it will not have a ::/0 route in its routing table.

Comprehensive and Detailed In-Depth Explanation:

Understanding the IS-IS Topology in the Question:

R1 (Level-1 Router) is connected to R2 (Level-1-2 Router).

R2 connects Level-1 and Level-2 areas, making it an inter-area router.

R3 (Level-2 Router) connects to R2.

The loopback addresses are:

R1: 10.0.1.1/32

R2: 10.0.2.2/32

R3: 10.0.3.3/32

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

This command forces R1 to advertise a default route (0.0.0.0/0) to Level-1 routers.

Level-1 routers (like R1) do not have visibility into Level-2 routes unless a default route is provided by an L1-L2 router (R2 in this case).

Analyzing Each Option:

Option A (TRUE):

If R1 pings an unknown address like 10.0.4.4, it will use the default route if available. However, if no such route exists, it will not send any packets.

This behavior is expected, so this statement is true.

Option B (TRUE):

10.0.2.2 (R2) is a Level-1-2 router, and it can communicate with 10.0.3.3 (R3), which is a Level-2 router.

Since R2 and R3 are both in Level-2, they can exchange routes.

So, 10.0.2.2 can ping 10.0.3.3. This statement is true.

Option C (TRUE):

10.0.1.1 (R1) is a Level-1 router, and 10.0.2.2 (R2) is a Level-1-2 router.

Since R2 is Level-1-2, it shares Level-1 routes with R1, allowing communication between R1 (10.0.1.1) and R2 (10.0.2.2).

Therefore, this statement is true.

Option D (FALSE - Correct Answer):

10.0.1.1 (R1) is a Level-1 router, which means it only knows about Level-1 routes.

10.0.3.3 (R3) is a Level-2 router, and its route is only known by Level-2 routers (R2 & R3).

Since Level-1 routers do not learn Level-2 routes directly (unless specific redistribution is done), R1 does not have a route to 10.0.3.3.

Therefore, R1 (10.0.1.1) cannot ping R3 (10.0.3.3), making this statement false.

Conclusion:

The false statement is Option D (10.0.1.1 can ping 10.0.3.3).

Comprehensive and Detailed In-Depth Explanation:

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 References:

OSPF Neighbor Formation and Area Design Principles

Troubleshooting OSPF Area Mismatches and Configuration Issues

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

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)

References:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 – OSPF Stub, Totally Stub, and NSSA Areas

OSPF LSA Types and External Route Restrictions

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.

1. Understanding VLAN Aggregation in Huawei Switches

VLAN aggregation is a technique that groups multiple VLANs (sub-VLANs) under a single Super-VLAN.

Super-VLANs do not have member interfaces but include multiple Sub-VLANs that share a common gateway (VLANIF interface).

2. Inter-Sub-VLAN Communication Requirement

By default, hosts in different sub-VLANs cannot communicate directly.

To enable communication between different sub-VLANs within the same Super-VLAN, an inter-sub-VLAN proxy must be enabled.

This is done using the inter-sub-vlan-proxy enable command in the VLANIF interface of the Super-VLAN.

3. Correct Command Usage

The command format is:

shell

CopyEdit

supervlan inter-sub-vlan-proxy enable

This command must be executed under VLANIF 10, corresponding to the Super-VLAN.

4. Why is the Answer "supervlan"?

The missing parameter in the command should be supervlan, because it is used to enable communication between Sub-VLANs under a Super-VLAN.

This is a specific Huawei command used in HCIP-Datacom-Advanced Routing & Switching Technology certification.

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

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

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

Comprehensive and Detailed In-Depth Explanation:

1. Understanding Port Security Modes

Port security is used to control access on a switch port based on MAC addresses. If a MAC address violation occurs (e.g., static MAC address flapping), the switch can take different actions based on the configured security mode.

Security Mode

Description

Restrict

Drops the violating packets and logs the violation by generating an alarm.

Protect

Drops the violating packets but does not generate an alarm.

Shutdown

Places the interface into error-disabled (error-down) state and logs an alarm.

2. Matching Each Security Mode with Its Operation

Protect Mode:

The switch drops the packets from the unauthorized MAC address.

No alarm is generated or logged.

Correct Mapping: "Discards the packets that trigger static MAC address flapping only and does not report an alarm."

Restrict Mode:

The switch drops the packets from the unauthorized MAC address.

An alarm is generated and logged in the system.

Correct Mapping: "Discards the packets that trigger static MAC address flapping and reports an alarm."

Shutdown Mode:

The switch shuts down the interface by placing it into the error-down state.

An alarm is generated and logged.

Correct Mapping: "Sets the interface state to error-down and reports an alarm."

Comprehensive and Detailed In-Depth Explanation:

Understanding the Table and Traffic Suppression Configuration

Port Name

Type

Rate (Min/Max)

Mode

Action

Punish-Status

Trap

Log

Int

Last-Punish-Time

GE0/0/1

Broadcast

1000 / 2000

Pps

Block

Normal

Off

On

90

-

GE0/0/1

Multicast

1000 / 2000

Pps

Block

Normal

Off

On

90

-

GE0/0/1

Unicast

1000 / 2000

Pps

Block

Normal

Off

On

90

-

Key Observations from the Table:

Traffic suppression (or rate limiting) is configured on interface GE0/0/1 for broadcast, multicast, and unicast traffic.

Thresholds:

Min rate: 1000 pps (packets per second)

Max rate: 2000 pps

If the traffic exceeds the configured threshold (2000 pps), the action is to "Block".

The interface is still "Normal" (not shut down), meaning exceeding 2000 pps does not disable the port.

Logging is enabled (Log: On), but trapping (Trap: Off) is disabled.

Analysis of Each Answer Choice

A. "When the average rate of unknown multicast packets is 1500 pps, GE0/0/1 blocks the multicast packets." ❌ (False)

The blocking threshold for multicast is 2000 pps (Max rate).

If the rate is 1500 pps, it is still below the threshold, so traffic is not blocked yet.

❌ Statement A is incorrect.

B. "When the average rate of known unicast packets is 2500 pps, GE0/0/1 is shut down." ❌ (False)

The table does not indicate that exceeding the max threshold (2000 pps) shuts down the interface.

Instead, it simply blocks packets exceeding the rate limit.

The interface remains "Normal", meaning it is not shut down.

❌ Statement B is incorrect.

C. "After broadcast packets are blocked on GE0/0/1, broadcast packets are forwarded only when their average rate is lower than 1000 pps." ❌ (False)

The minimum rate is 1000 pps, but there is no indication that traffic resumes forwarding only when it drops below this rate.

The configuration only states blocking when exceeding 2000 pps, but does not enforce a strict reactivation at 1000 pps.

❌ Statement C is incorrect.

D. "The administrator configures traffic suppression on GE0/0/1 of the switch." ✅ (True - Correct Answer)

The table explicitly shows that a traffic suppression policy is applied to broadcast, multicast, and unicast packets on GE0/0/1.

This confirms that the administrator has configured traffic suppression (rate limiting) on this interface.

✅ Statement D is correct.

Final Conclusion:

✅ Correct Answer: D. The administrator configures traffic suppression on GE0/0/1 of the switch.

Comprehensive and Detailed In-Depth Explanation:In OSPFv3, Link State Advertisements (LSAs) are used to describe the network topology and routing information. The behavior of LSAs in different area types, such as Not-So-Stubby Areas (NSSAs), is critical to understanding this question. Let’s break it down step by step:

Understanding Area 1 as an NSSA:

An NSSA (Not-So-Stubby Area) is a special type of OSPF area that allows the importation of external routes (Type 7 LSAs, also known as NSSA LSAs) while preventing the flooding of AS-External LSAs (Type 5 LSAs) from other areas into the NSSA. This is done to reduce the amount of routing information within the area while still allowing limited external route advertisement.

In an NSSA, external routes (like the one imported by R1, 2000::1/128) are advertised as Type 7 LSAs within the NSSA and are translated into Type 5 LSAs by the Area Border Router (ABR) when they need to be advertised into other areas (e.g., the backbone area, Area 0). However, Type 5 LSAs (AS-External-LSAs) are not flooded into the NSSA itself.

Analyzing the LSAs in the Options:

A. Inter-Area-Prefix-LSA: These LSAs (Type 3 LSAs in OSPFv3) are used to advertise prefixes between areas. In an NSSA, Inter-Area-Prefix-LSAs can exist because they are used by the ABR to summarize and advertise routes from other areas (like Area 0) into Area 1. Therefore, this LSA exists in Area 1.

B. NSSA LSA: These are Type 7 LSAs in OSPFv3, specific to NSSAs. They are used to advertise external routes (like the 2000::1/128 route imported by R1) within the NSSA. Since Area 1 is an NSSA and R1 is importing an external route, NSSA LSAs exist in Area 1.

C. Intra-Area-Prefix-LSA: These LSAs (Type 1 and Type 2 LSAs, or their OSPFv3 equivalents) are used to advertise prefixes within the same area. In Area 1, Intra-Area-Prefix-LSAs exist to describe the internal topology and prefixes of Area 1, so this LSA is present.

D. AS-External-LSA: These are Type 5 LSAs in OSPFv3, used to advertise external routes throughout the OSPF domain (outside the autonomous system). However, in an NSSA, Type 5 LSAs are not flooded into the area to keep it stubby-like. Instead, external routes are advertised as Type 7 LSAs (NSSA LSAs) within the NSSA and are only converted to Type 5 LSAs by the ABR when exiting the NSSA. Therefore, AS-External-LSAs (Type 5 LSAs) do not exist in Area 1.

Role of R1 and the External Route:

R1 is importing the external route 2000::1/128 into OSPFv3, which means it acts as an Autonomous System Boundary Router (ASBR) within Area 1. As an ASBR in an NSSA, R1 advertises this external route as a Type 7 LSA (NSSA LSA) within Area 1. This Type 7 LSA is then translated by the ABR (if R1 is not the ABR, or by another ABR in Area 1) into a Type 5 LSA for advertisement into other areas (e.g., Area 0). However, the Type 5 LSA (AS-External-LSA) does not exist within Area 1 itself, as NSSAs block Type 5 LSAs.

Conclusion:

Given that Area 1 is an NSSA, and Type 5 LSAs (AS-External-LSAs) are not flooded into NSSAs, the AS-External-LSA does not exist in Area 1. All other LSAs (Inter-Area-Prefix-LSA, NSSA LSA, and Intra-Area-Prefix-LSA) can exist in Area 1 based on the topology and the role of R1 as an ASBR.

Therefore, the correct answer is D, as AS-External-LSAs do not exist in Area 1.

References to HCIP-Datacom-Advanced Routing & Switching Technology Documents:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0, Section on OSPFv3: OSPF Area Types and LSA Types (specifically NSSA behavior, Type 5 and Type 7 LSAs).

HCIP-Datacom-Advanced Routing & Switching Technology V1.0, Chapter on OSPF Routing Protocols: LSAs in Different Area Types and External Route Handling.

LSAs and Their Origin Router Associations:

Link-LSA: Origin Router = 10.0.1.1

Intra-Area-Prefix-LSA: Origin Router = 10.0.4.4

Network-LSA: Origin Router = 10.0.3.3

Inter-Area-Prefix-LSA: Origin Router = 10.0.1.1