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 Switching

MPLS (Multiprotocol Label Switching) operates by adding labels to packets to enable fast switching across an MPLS domain.

Labels are swapped at each router (LSR - Label Switch Router) based on the LFIB (Label Forwarding Information Base).

When an MPLS packet reaches a router, it checks the incoming label and swaps it with an outgoing label as per its label forwarding table.

The label value "3" is the implicit null label, which is used for PHP (Penultimate Hop Popping).

2. Analyzing the MPLS Label Flow in the Figure

At PE1: The packet enters the MPLS domain and is labeled with 1033.

At P1: P1 forwards the packet based on label 1033.

At P2:

P2 receives label 1033 and swaps it with label 3 (as per the figure).

Label 3 (implicit null) means that the label is removed before reaching PE2 (PHP - Penultimate Hop Popping).

This ensures that PE2 receives a pure IP packet without an MPLS label.

3. Evaluating Each Answer Option

Option A: "The label value is 3." → Incorrect.

Label 3 (implicit null) is not actually sent to PE2.

Instead, P2 removes the label before sending the packet to PE2.

Option B: "There is no label." → Correct.

Since P2 performs PHP (Penultimate Hop Popping), the label is removed, and PE2 receives only an IP packet.

Option C: "The label value is 1033." → Incorrect.

Label 1033 was used earlier in the MPLS path but was swapped out before reaching PE2.

Option D: "The label values are 3 and 1033." → Incorrect.

Only one label is present at a time.

Label 1033 was swapped for label 3, but label 3 was removed before reaching PE2.

Final Answer:

Answer: B (There is no label).

HCIP-Datacom-Advanced Routing & Switching Technology References:

MPLS Label Forwarding Mechanism

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

MPLS Label Swapping and Label Forwarding Table (LFIB)