H35-210_V2.5 HCIA-Access V2.5 Exam Questions and Answers

ONU Activation Overview :

When an ONU (Optical Network Unit) is added to the OLT, it may initially be in a deactivated state ( Control flag = deactive ).

To bring the ONU online, it must be explicitly activated using the ont activate command.

Command Usage :

The ont activate command is issued in GPON port mode to activate the ONU. Once activated, the ONU transitions to the Online state and begins normal operation.

Why TRUE?

The statement accurately describes the procedure for activating an ONU when the control flag is deactive.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: ONU Activation.

OLT Command Reference Guide by Huawei.

SNMP Overview :

SNMP (Simple Network Management Protocol) is used for managing and monitoring network devices.

TCP/IP Protocol Stack Layers :

Application Layer : Protocols that provide services directly to end users or applications (e.g., HTTP, FTP, SMTP).

Transport Layer : Protocols that ensure reliable data transfer (e.g., TCP, UDP).

Network Layer : Protocols that handle packet routing (e.g., IP).

Control Layer : Not a recognized layer in the TCP/IP model.

SNMP Placement :

SNMP operates at the Application Layer of the TCP/IP protocol stack. It uses UDP (User Datagram Protocol) as its transport protocol but resides at the application layer.

Why A?

SNMP is an application-layer protocol designed for network management tasks.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: SNMP Protocol.

RFC 1157: SNMP Protocol Specification .

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.

The transport layer in the OSI model is responsible for end-to-end communication and includes two main protocols: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) .

IP (Internet Protocol) : Works at the network layer and is responsible for routing packets across networks.

ARP (Address Resolution Protocol) : Works at the network layer and maps IP addresses to MAC addresses.

TCP : A connection-oriented protocol at the transport layer that ensures reliable communication through acknowledgments and retransmissions.

UDP : A connectionless-oriented protocol at the transport layer that provides faster but less reliable communication compared to TCP.

Since the question specifies a connectionless-oriented protocol at the transport layer, the correct answer is UDP .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: Transport Layer Protocols.

TCP/IP Protocol Suite Overview by Huawei.

Static routes are manually configured by network administrators and are not dynamically updated by routing protocols. Let us analyze each option:

Option A :

Correct : Static routes are manually added to the routing table by the administrator. They remain unchanged unless manually modified or removed.

Option B :

Incorrect : Static routes are not automatically recalculated when the network topology changes. If a static route becomes invalid due to a topology change, the administrator must manually update it.

Option C :

Incorrect : Static routes are not learned from other routing protocols. Routes learned from dynamic protocols (e.g., OSPF, RIP) are dynamic routes, not static routes.

Option D :

Incorrect : Static routes are not preconfigured on routers before delivery. They are configured by administrators based on the network design.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: Static Routing.

Routing Protocols and Static Routes by Huawei.

QinQ Overview :

QinQ (IEEE 802.1ad) is a double-tagging mechanism that adds an outer VLAN tag to an already tagged packet.

It is commonly used in carrier networks to extend VLAN capacity and support hierarchical VLAN architectures.

VLAN Types :

Sub VLAN : Part of a Super VLAN configuration, used for IP address conservation. Does not support QinQ.

Common VLAN : Supports only single-tag VLANs. Does not support QinQ.

Super VLAN : Aggregates multiple Sub VLANs for IP address sharing. Does not support QinQ.

Smart VLAN : Specifically designed to support advanced features like QinQ and VLAN stacking.

Why D?

Smart VLAN is the only VLAN type that supports QinQ and VLAN stacking, making it the correct choice.

Thus, the correct answer is D .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Design.

IEEE 802.1ad QinQ Standards .

DHCP Relay Agent Functionality :

A DHCP relay agent forwards DHCP packets between clients and servers located in different subnets.

It modifies the packet headers to ensure proper delivery:

Converts broadcast packets from clients into unicast packets to forward them to the DHCP server.

Converts unicast responses from the DHCP server back into broadcast packets for delivery to clients.

Why C?

The DHCP relay agent performs bidirectional conversion between broadcast and unicast packets to facilitate communication between clients and servers in different subnets.

Other Options :

A : Incorrect because DHCP relay agents do not convert packet types (e.g., Ethernet vs. non-Ethernet).

B : Incorrect because the relay agent handles both broadcast-to-unicast and unicast-to-broadcast conversions.

D : Incorrect because the relay agent modifies unicast packets during forwarding.

Thus, the correct answer is C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: DHCP Relay Agent.

RFC 2131: DHCP Protocol Specification .

Let us analyze each protection scheme:

Type A Protection :

Protects only the trunk fiber (between the OLT and the splitter).

Does not protect branch fibers.

Type B Single-Homing Protection :

Protects the trunk fiber but does not extend protection to branch fibers.

Type B Dual-Homing Protection :

Similar to Type B single-homing but uses two OLTs for redundancy. Still does not protect branch fibers.

Type C Protection :

Provides end-to-end protection , covering both the trunk and branch fibers.

Uses redundant fibers and splitters to ensure continuity in case of failures in either the trunk or branch fibers.

Thus, the correct answer is D , as Type C protection is the only scheme that protects branch fibers.

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON Protection Mechanisms.

GPON Redundancy and Protection Schemes by Huawei.

When configuring a static route, certain parameters are required for the route to function correctly. Let us analyze each option:

Option A :

Incorrect : The preference (or administrative distance) is optional. If not specified, the router uses the default preference value for static routes.

Option B :

Incorrect : While the next-hop IP address is commonly used in static route configuration, it is not always mandatory. For example, you can specify an outgoing interface instead of a next-hop address.

Option C :

Incorrect : The subnet mask is essential for defining the network prefix of the destination network. Without the mask, the router cannot determine the range of IP addresses covered by the route.

Option D :

Correct : The subnet mask is mandatory when configuring a static route. It defines the network portion of the destination IP address, enabling the router to match packets to the correct route.

Thus, the correct answer is D .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: Static Route Configuration.

IP Routing and Subnet Masks 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.

Routing decisions prioritize the  longest prefix match . The destination 9.1.4.5 matches both 9.0.0.0/8 (subnet mask 255.0.0.0) and 9.1.0.0/16 (subnet mask 255.255.0.0). The /16 mask is longer, so the second route (9.1.0.0/16) is selected. Protocol priority (OSPF’s 10 vs. RIP’s 100) and metrics (cost) are irrelevant here because the longest prefix takes precedence.

GPON (Gigabit Passive Optical Network) is a fiber-optic access technology that integrates seamlessly with VoIP (Voice over IP) technology to provide voice services alongside data and video services. This integration allows GPON to support triple-play services (voice, data, and video) over a single fiber infrastructure.

xDSL : Refers to copper-based technologies and is not directly integrated with GPON.

Ethernet : While GPON uses Ethernet frames for data transmission, it is not the primary integration point for application scenarios.

WLAN : Wireless LAN is a separate technology and not directly integrated with GPON.

VoIP : Voice over IP is a key application scenario for GPON, enabling high-quality voice services over fiber-optic networks.

This is explicitly mentioned in the HCIA Huawei ACCESS documentation, which highlights the role of GPON in delivering converged services, including VoIP.

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON Technology and Applications.

Triple-Play Services in GPON Networks by Huawei.

Stacking VLAN (QinQ):  Adds an outer VLAN tag (double tagging).

ADSL2+ Specifications :

Downstream Rate : ADSL2+ supports a maximum downstream rate of 24 Mbit/s under ideal conditions.

Upstream Rate : The maximum upstream rate is typically 1 Mbit/s to 3.5 Mbit/s , depending on the line conditions.

Transmission Distance : The maximum transmission distance for ADSL2+ is approximately 5.5 km , not 6.5 km. Beyond this distance, signal attenuation becomes significant, reducing performance.

Why FALSE?

The statement incorrectly states that the maximum transmission distance is 6.5 km, which exceeds the typical range for ADSL2+.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: ADSL2+ Specifications.

ADSL2+ Technical Overview by Huawei.

DBA (Dynamic Bandwidth Allocation) :

DBA is a mechanism in GPON networks that dynamically allocates upstream bandwidth among ONUs based on their traffic demands.

Functions of DBA :

Improves upstream bandwidth utilization : DBA ensures efficient use of the limited upstream bandwidth by allocating it dynamically to ONUs as needed.

Does not increase total upstream bandwidth : The total upstream bandwidth of a PON port is fixed and determined by the hardware. DBA optimizes how this bandwidth is used.

Does not affect downstream bandwidth : Downstream bandwidth is shared via broadcasting and is not managed by DBA.

Does not add more ONUs : The number of ONUs supported by a PON port depends on hardware capacity, not DBA.

Why C?

DBA improves the efficiency of upstream bandwidth utilization by dynamically allocating resources.

Thus, the correct answer is C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON DBA Mechanism.

GPON Dynamic Bandwidth Allocation by Huawei.

Huawei OLT supports:

Transparent:  No modification.

Translate:  Replaces the VLAN ID.

NMS configuration requires:

A:  Device name for identification.

B:  SNMP community string for authentication.

C:  IP address for communication.

D (Incorrect):  Routing is handled by network devices, not NMS parameters.

GPON Wavelengths :

GPON networks use specific wavelengths for upstream and downstream transmission:

Downstream (OLT to ONU) : 1490 nm.

Upstream (ONU to OLT) : 1310 nm.

Optional CATV overlay : 1550 nm (used for video services).

Why 1490 nm?

The ITU-T G.984.x standards specify 1490 nm as the wavelength for downstream data transmission in GPON networks. This wavelength is chosen for optimal performance in fiber-optic communication.

Other Options :

850 nm : Used in multimode fiber for short-distance communication, not in GPON.

1310 nm : Used for upstream transmission in GPON.

1550 nm : Optional wavelength for CATV overlay, not for standard downstream data.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON Wavelengths.

ITU-T G.984.x Standards for GPON .

Comprehensive and Detailed Step by Step Explanation:

A (Incorrect):  XGS-PON encrypts the  payload , not the entire packet.

Testing Optical Transmit Power :

Testing the optical transmit power of an ONU involves measuring the power output at its upstream port.

Key Considerations :

Wavelength : The upstream wavelength for GPON/XGS-PON is 1310 nm , so selecting this wavelength is correct.

Power Meter Type : A common power meter is not suitable for testing optical power in live networks. Instead, a specialized optical power meter or an OLT-based monitoring tool should be used.

Why FALSE?

Using a common power meter is incorrect because it may not provide accurate readings or could disrupt network operation.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: ONU Optical Testing.

Optical Power Measurement Procedures by Huawei.

Service Types and Transmission :

AP/PC (Data Services) : These services are typically Ethernet-based and encapsulated into Ethernet frames before being transmitted over the PON network.

POTS (Voice Services) : Voice services can be either TDM-based or packetized. In modern GPON/XGS-PON systems, POTS is often packetized into Ethernet frames.

CATV (Video Services) : CATV uses a separate wavelength (1550 nm) for analog or digital video transmission.

Wavelength Division Multiplexing (WDM) :

GPON/XGS-PON systems use WDM to transmit multiple services over a single fiber:

One wavelength (1490 nm or 1577 nm) is used for data services (Ethernet).

Another wavelength (1550 nm) is used for CATV.

Analysis of Options :

Option A : Incorrect because CATV is not encapsulated into Ethernet frames; it uses a separate wavelength.

Option B : Correct because CATV uses a separate wavelength, and other services are encapsulated into Ethernet frames before PON transmission.

Option C : Incorrect because POTS services are typically packetized into Ethernet frames in modern systems, not directly encapsulated in GEM frames.

Option D : Incorrect because POTS is not transparently transmitted in modern GPON/XGS-PON systems.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON Service Encapsulation.

ITU-T G.984.x Standards for GPON .

Let us analyze each statement carefully:

Option A :

Incorrect : In inter-VLAN communication, hosts in different VLANs cannot directly communicate with each other because VLANs are isolated at Layer 2. Communication between VLANs requires a Layer 3 device (e.g., a router or Layer 3 switch).

Hosts do not learn the MAC addresses of devices in other VLANs. Instead, they communicate through a gateway (router or VLANIF interface), and the gateway handles the forwarding.

Option B :

Correct : A VLAN is indeed a broadcast domain . Devices within the same VLAN share the same broadcast traffic, while devices in different VLANs do not.

Option C :

Incorrect : A VLAN is not a collision domain. Collision domains are defined at the data link layer (Layer 2) and are associated with individual switch ports or hubs. VLANs are logical groupings that span multiple switch ports and do not represent collision domains.

Option D :

Correct : VLANIF interfaces (also called Switch Virtual Interfaces, SVIs ) are logical Layer 3 interfaces configured on switches to enable inter-VLAN routing. These interfaces allow communication between VLANs by acting as gateways for each VLAN.

Thus, the incorrect statements are A and C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Fundamentals.

Inter-VLAN Routing and VLANIF Interfaces by Huawei.

GPON networks use various protection mechanisms to ensure high availability and reliability. These mechanisms are classified into different types based on their scope and functionality:

Type A :

Protects only the trunk fiber (between the OLT and the splitter).

Does not protect branch fibers (between the splitter and ONUs).

Type B :

Protects the trunk fiber but does not provide simultaneous protection for branch fibers.

Type C :

Provides full protection for both the trunk and branch fibers.

Uses redundant fibers and splitters to ensure continuity in case of a failure.

Type D :

Not a standard GPON protection type.

Since the question specifies protection for both the backbone (trunk) and branch fibers, the correct answer is Type C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON Protection Mechanisms.

GPON Redundancy and Protection Schemes by Huawei.

Adding an ONT to the OLT :

Adding an ONT (Optical Network Terminal) to the OLT involves several steps, but the critical step is registering the ONT and binding it to the appropriate profile.

Key Steps :

DBA Profile : Configures dynamic bandwidth allocation for the ONT but is not mandatory during initial registration.

ONT Service Profile : Defines services (e.g., Internet, IPTV) but is applied after the ONT is added.

Add ONT and Bind Profile : Registers the ONT with the OLT and binds it to a pre-configured line profile. This is the essential step for adding an ONT.

ONT Line Profile : Configures the VLAN and service parameters but is created before adding the ONT.

Why C?

The most critical action when adding an ONT is to register it and bind it to a profile, ensuring it is recognized and operational within the network.

Thus, the correct answer is C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: ONT Registration.

OLT Command Reference Guide by Huawei.

A:  Weak optical power prevents ONT registration.

B:  Auto-find must be enabled for ONT discovery.

D:  Excessive optical power saturates the receiver.

Fiber Connection Loss Overview :

Fiber connection points introduce optical loss due to imperfections in alignment, reflections, or contamination.

Loss Comparison :

Movable Connector : Highest loss due to potential misalignment, contamination, and reflections.

Cord End Connector : Moderate loss, as these connectors are typically factory-polished and more stable than movable connectors.

Splicing : Lowest loss, as fusion splicing provides near-perfect alignment and minimal reflection.

Why C?

The order of losses from highest to lowest is: Movable connector > Cord end connector > Splicing .

Thus, the correct answer is C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: Fiber Optic Connections.

ITU-T G.652 Standards for Optical Fiber .