Huawei H35-210_V2.5 - HCIA-Access V2.5 Exam

OIDs (Object Identifiers) are numeric (e.g., 1.3.6.1.2.1.1.5), not letters. The statement in C is incorrect.

An OLT (Optical Line Terminal) is a key component in fiber-optic access networks, particularly in GPON and XGS-PON systems. It serves multiple roles:

Switch or Router Role :

The OLT acts as a Layer 2/Layer 3 switch or router, aggregating traffic from multiple ONUs (Optical Network Units) and forwarding it to the core network.

Multi-Service Provisioning Platform :

The OLT supports multiple services, including Internet access (data), voice (VoIP), and video (IPTV). It integrates these services over a single fiber infrastructure, making it a versatile platform for service providers.

Why TRUE?

The statement accurately describes the OLT's functionality as both a switch/router and a multi-service provisioning platform.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: OLT Functionality.

GPON System Architecture by Huawei.

A: GEM ports must map to T-CONTs for upstream QoS.

C: DBA dynamically allocates upstream bandwidth to T-CONTs.

B (Incorrect): Alloc-IDs must be unique per ONU.

Bridging ONU Configuration :

A bridging ONU acts as a transparent bridge between the PC and the OLT, forwarding traffic without modifying it.

VLAN Configuration for ETH1 :

VLAN 1 : The default VLAN, often reserved for management purposes. Using it for Internet access is not recommended.

Default Configuration : Leaving the port unconfigured may result in improper VLAN tagging or untagged traffic, leading to connectivity issues.

VLAN 4094 : Typically reserved for special purposes (e.g., QinQ termination) and is not suitable for general Internet access.

Native VLAN : Configuring a native VLAN ensures that untagged traffic from the PC is associated with the correct VLAN for Internet access.

Why D?

Configuring a native VLAN is the correct approach to ensure proper VLAN tagging and seamless Internet access for the PC connected to ETH1.

Thus, the correct answer is D .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Configuration.

GPON Bridging ONU Configuration Guide by Huawei.

Vectoring Classification :

Vectoring is primarily classified into two types based on the scope of crosstalk cancellation:

System-Level Vectoring (SLV) : Applies to all lines within a single DSLAM or cabinet.

Node-Level Vectoring (NLV) : Applies to lines across multiple DSLAMs or nodes.

However, these are not the only classifications. Other implementations, such as hybrid approaches, may also exist depending on the network design.

Why FALSE?

The statement incorrectly claims that vectoring is classified only as SLV and NLV, ignoring other possible implementations or variations.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VDSL2 Vectoring Architectures.

ITU-T G.993.5 Standards for Vectoring in VDSL2 .

VLAN Tag Translation :

VLAN tag translation is used to modify VLAN tags in packets as they pass through the OLT.

The tag-transform parameter determines how VLAN tags are handled during service flow creation.

Behavior of tag-transform = default :

When tag-transform is set to default, the OLT applies predefined rules for VLAN tag conversion based on the SVLAN (Service VLAN) attributes.

These rules vary depending on the SVLAN type (e.g., Common, QinQ, Stacking), resulting in different behaviors.

Why TRUE?

The statement accurately reflects the behavior of the tag-transform parameter when set to default. Different SVLAN attributes lead to different tag conversion rules.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Tag Translation.

OLT Configuration Guide by Huawei.

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 .