The HCIA-Access V2.5 Exam (H35-210_V2.5)

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 .

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.

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 .

A/B:  Basic network checks (IP configuration and physical connectivity).

C:  Inband and outband NMS IPs must be in different subnets to avoid conflicts.

Let us analyze each statement:

Option A :

Correct : WDM1r multiplexers can be flexibly deployed close to the Central Office (CO) or closer to the user, depending on network design requirements.

Option B :

Incorrect : While GPON and XGS-PON share the same ODN architecture, simply changing the optical modules on an ONU is insufficient to support XGS-PON. The ONU hardware and software must also be compatible with XGS-PON standards.

Option C :

Incorrect : The deployment of WDM1r multiplexers introduces additional optical loss, which must be accounted for in the calculation of optical link attenuation.

Option D :

Correct : GPON (1490 nm downstream, 1310 nm upstream) and XGS-PON (1577 nm downstream, 1270 nm upstream) use non-overlapping wavelengths, allowing them to coexist on the same ODN using WDM.

Thus, the incorrect statements are B and C .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: GPON and XGS-PON Coexistence.

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

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

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

Let us analyze each option:

Option A : Incorrect. A route does not include MAC addresses. It typically consists of a destination network, subnet mask, next-hop address, and outgoing interface.

Option B : Correct. IP routes are essential for guiding the forwarding of IP packets from the source to the destination. Routers use routing tables to determine the best path for packet delivery.

Option C : Incorrect. Routing is a concept at the network layer (Layer 3) of the OSI model, not the data link layer (Layer 2).

Option D : Incorrect. A route does not require the source address. It only needs the destination network, subnet mask, and next-hop information.

Thus, the correct answer is B .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: IP Routing Basics.

Routing Fundamentals in IP Networks by Huawei.

2.4 GHz Frequency Band :

The 2.4 GHz band is divided into 14 overlapping channels, each 20 MHz wide.

However, only three channels (e.g., Channels 1, 6, and 11 in North America) are non-overlapping and can be used simultaneously without interference.

Why TRUE?

By using non-overlapping channels (e.g., 1, 6, and 11), wireless networks can operate concurrently without significant interference.

Thus, the correct answer is A .

References:

HCIA Huawei ACCESS Official Documentation , Chapter: WLAN Frequency Bands.

IEEE 802.11 Standards for WLAN .