Default Behavior of ONUs :

By default, ONUs (Optical Network Units) connected to the same PON port of a Huawei OLT are isolated at Layer 2 .

This isolation ensures that ONUs cannot communicate directly with each other, even if they belong to the same service VLAN.

Why FALSE?

The statement incorrectly claims that ONUs can communicate with each other at Layer 2 by default. In reality, Layer 2 isolation is a security feature designed to prevent unauthorized communication between ONUs.

Enabling Communication :

If Layer 2 communication between ONUs is required, it must be explicitly enabled through configuration (e.g., by disabling Layer 2 isolation).

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON Security Features.

OLT Configuration Guide by Huawei.

GPON (Gigabit Passive Optical Network) is a fiber-based access technology that supports downstream bandwidth up to 2.5 Gbps and upstream up to 1.25 Gbps, far exceeding the bandwidth capabilities of DSL technologies. ADSL (up to 8 Mbps), ADSL2+ (up to 24 Mbps), and VDSL (up to 100 Mbps over short distances) are copper-based technologies with significantly lower maximum bandwidth compared to GPON.

Testing Board Reset :

Testing the reset functionality of an OLT board ensures that the board can recover from failures or configuration changes.

Methods for Testing Reset :

Hot Swap : Physically removing and reinserting the board tests its ability to initialize and function after a reset.

RESET Button : Pressing the physical RESET button on the board forces a hardware reset, verifying recovery capabilities.

Reset Command : Using CLI commands (e.g., reset board ) resets the board remotely, allowing verification of software-based recovery.

Why D?

All three methods are valid ways to test the reset functionality of an OLT board. Each method addresses different scenarios and ensures comprehensive testing.

Thus, the correct answer is D .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: OLT Maintenance.

OLT Hardware and Software Reset Procedures by Huawei.

Double-Tagged VLANs :

Double-tagging involves adding two VLAN tags to a packet:

Inner VLAN Tag : Identifies users or devices.

Outer VLAN Tag : Identifies services or networks.

VLAN Attributes :

QinQ : Adds an outer VLAN tag to an already tagged packet, enabling double-tagging.

Stacking : Similar to QinQ but less commonly used.

Common : Supports only single-tag VLANs.

Scenario Analysis :

The university requires double-tagging for user and service identification.

The QinQ attribute is specifically designed for this purpose.

Why C?

The QinQ attribute supports double-tagging, making it the correct choice for this scenario.

Thus, the correct answer is C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Design.

IEEE 802.1ad QinQ Standards .

VLANs (Virtual Local Area Networks) are used to logically segment a network into smaller broadcast domains. VLANs can be categorized using various methods:

Port-Based VLANs :

VLAN membership is determined by the switch port to which a device is connected.

Example: Ports 1–10 belong to VLAN 10, and ports 11–20 belong to VLAN 20.

Protocol-Based VLANs :

VLAN membership is determined by the protocol type (e.g., IPv4, IPv6, or AppleTalk) in the packet header.

MAC Address-Based VLANs :

VLAN membership is determined by the MAC address of the device.

Example: Devices with specific MAC addresses are assigned to VLAN 10.

Physical Location-Based VLANs :

VLANs are not categorized based on physical locations. While VLANs can be used to group devices in different physical locations, this is not a standard method of VLAN categorization.

Thus, the correct answer is C , as VLANs are not categorized based on physical locations.

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Technologies.

VLAN Segmentation Methods by Huawei.

SC (Large Square Head):  Square connector with a push-pull design.

FC (Round Head):  Round connector with a screw-on mechanism.