H12-831_V1.0 Exam Dumps : HCIP-Datacom-Advanced Routing & Switching Technology V1.0

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:

1. Understanding MPLS Label Forwarding Information

The output of the display mpls lsp command shows the Label Forwarding Information Base (LFIB) used by the router to forward MPLS packets.

Each entry consists of:

FEC (Forwarding Equivalence Class): The destination IP prefix.

In Label / Out Label: Incoming label (received) and outgoing label (sent).

In IF / Out IF: Incoming and outgoing interfaces.

2. Analyzing the Given LSP Table

FEC (Destination IP)

In Label

Out Label

Outgoing Interface

1.1.1.1/32

3

NULL

-

2.2.2.2/32

NULL

3

GE0/0/1

2.2.2.2/32

1026

3

GE0/0/1

3.3.3.3/32

NULL

1027

GE0/0/1

3.3.3.3/32

1027

1027

GE0/0/1

Key Observations:

NULL means the label is removed (Penultimate Hop Popping - PHP).

Label 3 is the implicit null label, meaning the label is removed before sending to the next router.

For destination 3.3.3.3, the router adds label 1027 before forwarding it to GE0/0/1.

3. Evaluating Each Answer Option

Option A: "Before forwarding a packet destined for 2.2.2.2, the device adds label 3 to the packet." → Incorrect.

The output shows that packets destined for 2.2.2.2 have the NULL (label 3) entry, which means the label is removed before forwarding, not added.

Option B: "Before forwarding a packet destined for 1.1.1.1, the device adds label 3 to the packet." → Incorrect.

The entry 1.1.1.1 → 3/NULL means the label is removed (PHP), so the device does not add label 3.

Option C: "Before forwarding a packet destined for any IP address, the device removes labels from the packet." → Incorrect.

The device removes labels only for some destinations (e.g., 1.1.1.1 and 2.2.2.2), but it adds label 1027 for 3.3.3.3.

Not all IPs have their labels removed.

Option D: "Before forwarding a packet destined for 3.3.3.3, the device adds label 1027 to the packet." → Correct.

The entry 3.3.3.3 → NULL/1027 means that the router adds label 1027 before forwarding packets to GE0/0/1.

Final Answer:

Answer: D (Before forwarding a packet destined for 3.3.3.3, the device adds label 1027 to the packet).

HCIP-Datacom-Advanced Routing & Switching Technology References:

Understanding MPLS LDP (Label Distribution Protocol) and LFIB

Implicit Null (Label 3) and Penultimate Hop Popping (PHP)

MPLS Label Swapping and Forwarding Process

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