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

ODN loss factors:

A: Intrinsic fiber attenuation (~0.2 dB/km).

B: Splitter insertion loss (e.g., 1:32 splitter ≈17 dB).

D/E: Connector/splice losses (0.1–0.5 dB per point).

B: Single-tagging requires matching service/user VLAN IDs.

C: VLAN-to-GEM mapping enables service segregation.

D: QinQ uses outer VLAN for aggregation and inner VLAN for user identification.

XGS-PON Wavelengths :

XGS-PON (10-Gigabit Symmetric Passive Optical Network) uses specific wavelengths for upstream and downstream transmission:

Downstream (OLT to ONU) : 1577 nm.

Upstream (ONU to OLT) : 1270 nm.

Why 1577 nm?

The ITU-T G.9807.1 standard specifies 1577 nm as the downstream wavelength for XGS-PON. This wavelength is chosen to avoid interference with GPON, which uses 1490 nm for downstream transmission.

Other Options :

1490 nm : Used for downstream transmission in GPON, not XGS-PON.

1310 nm : Used for upstream transmission in GPON, not XGS-PON.

1290 nm : Not a standard wavelength in PON technologies.

Thus, the correct answer is C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: XGS-PON Wavelengths.

ITU-T G.9807.1 Standards for XGS-PON .

Traffic Classification Overview :

Traffic classification is used to identify and prioritize different types of traffic on the network.

The OLT (Optical Line Terminal) supports various methods for classifying traffic based on VLAN tags, packet priorities, and service encapsulation.

Supported Technologies :

User-side VLAN : Classifies traffic based solely on VLAN tags. This is a basic method but does not consider packet priority or service type.

VLAN + user-side packet priority : Combines VLAN tags with packet priority (e.g., DSCP or 802.1p values) for more granular classification.

VLAN + user-side service encapsulation : Combines VLAN tags with service-specific encapsulation, but this is less commonly used.

User-side service encapsulation : Focuses only on service encapsulation without considering VLAN tags or packet priority.

Why B?

The combination of VLAN tags and user-side packet priority provides the most effective and widely supported traffic classification method. It allows the OLT to classify traffic based on both VLAN membership and priority levels, ensuring efficient QoS (Quality of Service) management.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: Traffic Classification.

GPON Traffic Management by Huawei.

GPON Overview :

GPON (Gigabit Passive Optical Network) is a fiber-optic access technology standardized by the ITU-T (International Telecommunication Union) under the G.984.x series of standards.

It is not based on Ethernet but uses its own framing structure called GEM (GPON Encapsulation Method) for data transmission.

IEEE 802.3ah :

IEEE 802.3ah is the standard for EPON (Ethernet Passive Optical Network) , which is a competing technology to GPON.

EPON uses Ethernet frames for data transmission and is standardized by the IEEE, unlike GPON, which is standardized by ITU-T.

Why FALSE?

The statement incorrectly associates GPON with IEEE 802.3ah, which applies to EPON, not GPON.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON vs. EPON.

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

VLAN Attributes :

Common VLAN : Used for standard VLAN tagging, where a single VLAN tag identifies the VLAN.

QinQ VLAN : Adds an additional VLAN tag for double-tagging, typically used in carrier networks.

Sub VLAN : Part of a Super VLAN configuration, used for IP address conservation.

Stacking VLAN : Similar to QinQ, used for double-tagging.

Scenario Analysis :

The school uses a single VLAN tag to identify services by type (e.g., student, faculty, administration).

Since only one VLAN tag is used, the appropriate VLAN attribute is Common .

Why A?

Common VLAN is the simplest and most suitable choice for scenarios requiring single-tag VLAN identification.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: VLAN Design.

IEEE 802.1Q VLAN Tagging Standards .