Practice Free H35-211_V2.5 HCIP-Access V2.5 Exam Questions Answers With Explanation

In Huawei’s 10G GPON (XG-PON) system, the split ratio defines how many Optical Network Units (ONUs) can be connected to a single Optical Line Terminal (OLT) port through passive optical splitters.

According to ITU-T G.987.x standards and Huawei’s 10G GPON technical specifications, the maximum theoretical optical split ratio for 10G GPON is 1:128.

This means that a single OLT PON port can serve up to 128 ONUs through the passive optical distribution network (ODN).

While the physical capability supports 1:128, practical deployments often use lower ratios (e.g., 1:64) to maintain optical power budgets and ensure stable service quality, especially over longer fiber distances or when optical losses are high.

Huawei’s MA5800/EA5800 series OLTs, which support 10G GPON, comply fully with this standard, enabling 1:128 maximum splitting with appropriate ODN design.

Therefore, the correct answer is C. 1:128.

References (Aligned with HCIP-Access V2.5 and Huawei Technical Documentation):

HCIP-Access V2.5 Study Guide – “Huawei Campus Network Overview” Chapter, Section: GPON and 10G GPON Overview

Huawei 10G GPON (XG-PON) Technical White Paper

ITU-T G.987.1: 10-Gigabit-capable Passive Optical Networks (XG-PON) – General Characteristics

Huawei MA5800/EA5800 Product Description – Optical Port Split Ratio Specifications

A rogue ONU that transmits out of schedule or at abnormal optical levels can disrupt upstream time-slotting on the PON, causing collision and interference. This can force other ONUs on the same PON to deregister or flap frequently. Huawei OLTs provide rogue ONU detection/isolation to protect the PON.

In an H.248 (Megaco) control model, the MGC is the controller that issues provisioning/connection-control commands such as Add, Modify, Subtract, AuditValue, AuditCapabilities to the MG. The MG (Media Gateway) can initiate only specific messages toward the MGC to announce state changes or report detected events—namely ServiceChange (to indicate restart, failure, availability changes, etc.) and Notify (to report observed events collected per event descriptor). Therefore, among the listed options, the commands that the MG itself can send are ServiceChange and Notify.

For Huawei uplink protection (STH-NNI port protection) with workmode timedelay, the mandatory steps are:

Create/define the protection group with the protect-target and workmode timedelay;

Add member ports with roles (work/protect);

Enable the protection group.

Interface-level timers like offline-tx-off-time under the physical interface are not required for standard timedelay protection operation and are therefore optional.

With IGMP Snooping/Proxy on access devices (such as Huawei OLTs), multiple receiver joins for the same (VLAN, Group) are aggregated. The OLT maintains a per-group member table and typically forwards a single upstream IGMP Join toward the multicast router (or querier) for that group, regardless of how many downstream users in that VLAN have joined. Additional local joins add downstream interfaces to the OLT’s table but do not trigger extra upstream joins per user. Hence, stating that two same-program viewers cause “two join messages” upstream is wrong.

Huawei OLTs support trust/remark mechanisms that can inherit (copy) user packet priorities (for example, trusting incoming 802.1p or DSCP to drive forwarding queues) and also support locally configured priorities (policy-based remarking/mapping on the OLT) to enforce service differentiation. Thus, both priority inheritance and local priority configuration are supported, making the statement Right.

For intercommunication across VLANs—especially for voice between ONUs—ARP Proxy is configured on the OLT so the OLT responds to ARP on behalf of endpoints and bridges traffic across VLAN boundaries without exposing the full L3 gateway to each segment.

A: “Saving IP addresses” is not the defining difference; ARP Proxy’s function is ARP mediation to enable L2/L3 reachability.

B: Both features target intercommunication, not isolation.

D: A VLAN service-profile is planned and applied from the OLT side to ONUs; it is not “configured on the ONU” directly for this purpose.

The statement is wrong. SIP explicitly allows several header fields to appear multiple times within a request or response—for example, Via (one per hop), Route, Record-Route, and Contact may legitimately occur more than once. This is fundamental to SIP routing behavior, where each proxy appends a new Via entry. RFC 3261 explains processing based on the top Via among potentially multiple Via headers, which directly contradicts the claim that “a single information value never appears multiple times

A is consistent with Huawei L2 multicast practice: global L2 multicast/IGMP snooping parameters can be set and then take effect for multicast VLANs involved in service provisioning.

B reflects the forwarding/CPU-punt behavior on access line cards: IGMP Reports/Leaves from users are recognized by board logic and processed by the control plane to update multicast state.

C matches default service control on BTV/IPTV access where a default program limit (commonly 8) per user applies unless adjusted by policy/profile.

D is incorrect: when IGMP match mode is disabled, multicast programs are not required to be pre-provisioned as channels; groups can be learned dynamically by IGMP. Preconfiguring channels is needed when match mode is enabled (channel matching enforced).

B is incorrect: NCE deployment options (on-premises, private cloud, public cloud) are determined by service and architecture needs, not by which vendor provides the physical devices.

D is incorrect: Deployment duration varies with hardware platforms, virtualization stacks, and software environments; it is not the same across scenarios.

A and C are correct: NCE exposes NBIs for OSS integration and operates at the analysis/control layer to collect, analyze, and predict issues using big-data/AI capabilities.

On Huawei OLTs, the standard QoS pipeline for upstream packets is: first perform traffic classification (identify flows), then marking (set CoS/DSCP as required), next apply traffic policing (rate-limit and color traffic), followed by congestion avoidance (AQM such as RED/WRED), and finally congestion management (queue scheduling/priority queuing). This ordered sequence ensures correct identification and marking before any rate enforcement, and that packets encounter AQM prior to scheduler-based dequeue.

On Huawei access devices/OLTs, VoIP/H.248 setup typically includes:

In voip view, configure media IP with gateway:

ip address media – e.g., ip address media 10.10.10.10 10.10.10.1.

Configure signaling IP without a gateway parameter:

ip address signaling – e.g., ip address signaling 10.10.10.10.

Add/enter the H.248 interface and apply properties with if-h248 attribute ….

It’s common to reset/enable the MG interface after attribute changes; many guides show reset coldstart (or reset) issued under the H.248 interface to activate the interface.

Authoritative configuration examples show media takes an IP and gateway, but signaling takes only the IP. Therefore, option D (attempting to configure signaling with a gateway parameter) is incorrect. Options A and C match documented syntax and workflow. Option B reflects the documented practice of issuing a reset (often written as reset coldstart) under the H.248 interface to apply/enable, as shown in Huawei-focused configuration guides.

This statement is wrong. In U2000, network elements (NEs) can be added by multiple methods, including batch addition/import and automatic discovery, not just one-by-one during a live access session. U2000 supports template-based onboarding and batch operations to improve efficiency for large-scale deployments.

Huawei’s E2E pre-connection ODN (pre-connectorized ODN) adopts factory-pre-terminated cables, closures and splitter modules. Features highlighted in HCIP-Access V2.5 include: splicing-free quick installation (raising build efficiency and reducing skill/tool dependence), compact pre-connected splitter boxes, distributed splitting that shortens drop lengths and reduces ducts/cables, and easy O&M because modules are plug-and-play with no field splicing.

Huawei’s alarm reference for PON ports lists the common possible causes of LOS (the OLT does not receive the expected optical signal) as:

The port laser is shut down;

The backbone optical fiber connected to the port is faulty;

All the ONTs/ONUs connected to the port are powered off or faulty;

(and potentially) port hardware faults.

These map directly to options D, B, and C. A rogue ONU generates specific “rogue ONU” alarms and is characterized by continuous/abnormal upstream emission; it is not a typical root cause of an LOS condition, which indicates absence of expected optical signal.

In AQM, high-priority queues are given more tolerant (larger) thresholds so they are less likely to be dropped early. Setting a smaller early-drop threshold for high priority would increase their loss probability, which contradicts QoS objectives—thus A is incorrect. Descriptions in B, C, and D align with Huawei’s treatment of congestion avoidance: RED/WRED proactively drops to stabilize queues and can reduce delay variation; tail drop at full buffer can lead to global TCP synchronization.

In Huawei IPTV access, when the OLT’s IGMP audit/authorization debug shows a negative program-rights/authorization result, it indicates that the user lacks permission for the requested multicast program group. This is distinct from port multicast bandwidth alarms (insufficient multicast bandwidth), IGMP snooping state malfunctions, or subscriber traffic shaping/bandwidth checks. Authorization failures map directly to “no permission to watch the program.”

IPv4 multicast (historically “Class D”) occupies the address block 224.0.0.0 through 239.255.255.255. Any upper bound of 238.255.255.255 is incorrect because it excludes the full 239/8 administratively scoped range. This is standardized in the IANA IPv4 Multicast Address Space registry and reflected in foundational multicast specifications.

In Huawei’s 10G GPON (Gigabit-capable Passive Optical Network) system, different optical wavelengths are used for upstream and downstream transmission to ensure bidirectional communication over a single fiber.

According to the ITU-T G.987.x series and Huawei’s Access Network Technical Documentation, the wavelength plan for 10G GPON (XG-PON) is as follows:

Downstream (OLT ? ONU): 1577 nm

Upstream (ONU ? OLT): 1270 nm

This separation of wavelengths allows both transmission directions to occur simultaneously using WDM (Wavelength Division Multiplexing) on the same optical fiber, minimizing interference.

Huawei OLTs such as the MA5800 and EA5800 series follow this standard exactly — supporting 10G GPON (XG-PON) with downstream at 1577 nm and upstream at 1270 nm.

Hence, the correct answer is 1577 nm.

Answer: B

References (Aligned with HCIP-Access V2.5 and Huawei Technical Sources):

HCIP-Access V2.5 Study Guide – “Huawei Campus Network Overview” Chapter, Section: PON Technology Overview

Huawei 10G GPON (XG-PON) Technical White Paper

ITU-T G.987.2: 10-Gigabit-capable Passive Optical Networks (XG-PON): Physical Media Dependent (PMD) Layer Specification

Huawei MA5800 Product Description – 10G GPON Port Wavelength Specifications

A: Incorrect — RADIUS typically uses UDP (1812/1813), while HWTACACS/TACACS+ uses TCP (port 49).

B: Incorrect — In RADIUS, only the user-password attribute is encrypted; fields are not selectively encrypted by user choice. TACACS+ can encrypt the entire payload.

D: Incorrect — Because RADIUS uses UDP, transport is not inherently reliable.

C: Correct — RADIUS and HWTACACS differ in message structure and returned attributes after authentication (e.g., RADIUS attribute–value pairs for access control/QoS/VLAN vs. HWTACACS command/privilege oriented responses). Thus the returned content/format differs between the two.

In IP multicast, only one copy per multicast group (program) is forwarded upstream, regardless of how many users are watching it. Replication happens downstream at the access/edge, not toward the core. Therefore the upstream traffic equals the number of active multicast groups × per-group bitrate:

20 programs × 2 Mbit/s = 40 Mbit/s.

This behavior is consistent with Huawei’s multicast feature descriptions and general multicast principles (IGMP/PIM), which explain that multicast traffic is sent as a single flow per group and replicated only where branching occurs, not multiplied by user count.

Huawei anti-DoS on access boards performs periodic detection. Ports with consecutive detections of abnormal traffic are placed into a blacklist/quarantine state. The system then applies a random back-off interval before re-detecting; if no further anomalies are found, the port can be automatically removed from the blacklist.

Huawei devices support independent mapping/remarking for inner and outer VLAN priorities (802.1p CoS) when QinQ is used. Operators can define distinct mapping tables or remark rules per tag. Option A is incorrect (priorities can be derived or remarked, not “must be” tag-in-packet), option C is incorrect because mapping profiles are configurable, and option D confuses VLAN IDs with priorities; inner/outer CoS can be mapped independently for inbound/outbound directions.

10G-EPON is designed for coexistence with EPON on the same ODN by using separate downstream wavelengths and dual-rate upstream mechanisms. Operators can realize a smooth upgrade at the OLT (local end) by inserting WDM mux/demux modules (or using dual-rate PON ports) while continuing to use the existing ODN fiber plant and splitters. This is a standard migration path emphasized in HCIP-Access materials for PON evolution.

IPTV over FTTH relies on multicast control; therefore the essential U2000 template is the IGMP template, which defines IGMP behaviors, program authorization binding, and multicast parameters used by the OLT/ONT. MGC applies to voice (VoIP), and SNMP pertains to NMS communication rather than IPTV service logic; value-added templates are not mandatory for basic IPTV.

In SIP, each proxy/server that forwards a request prepends its own address to the top of the Via header list. Therefore, as A’s INVITE traverses C, then D, then E, server E adds its Via at the top last, followed by D, then C below it. The message that reaches user B shows the Via stack (top?bottom) as E ? D ? C, which corresponds to option C. RFC 3261 states that the server transport uses “the value of the top Via header field” to determine response routing, confirming that the most recent hop is at the top

When the number of access users approaches or exceeds the single-layer VLAN space and services must be distinguished per user, Huawei recommends hierarchical VLAN (QinQ) on the uplink: map a customer VLAN (C-VLAN) at the access side and add a service/provider VLAN (S-VLAN) toward the aggregation/core, i.e., C ? S+C. This expands scalability beyond the ~4K single-VLAN limit while enabling precise user/service binding for large FTTH deployments (e.g., ~5K users under one OLT).

On Huawei OLTs, the service-port is a binding between the user-side access (ONT/port) and a VLAN/GEM channel, and it supports traffic policing (CAR/rate-limit) by referencing a traffic/queue profile. Traffic shaping (buffer-based smoothing, token bucket with queue drain) is provided on ports/queues or GEM/LLID directions, not on the service-port object itself. Therefore, shaping is not performed via the service-port; applying a traffic profile there enforces policing, not shaping.

The ONT details pane in eSight displays access-port attributes (admin/state, type), Ethernet rate/speed/duplex, and PON optical module telemetry such as temperature and Tx/Rx optical power for condition monitoring and troubleshooting.

According to IEEE 802.3av wavelength planning adopted by Huawei 10G-EPON, downstream uses 1577 nm and 10G upstream uses 1270 nm. In asymmetric coexistence, 1G-EPON upstream uses 1310 nm, but for 10G-EPON upstream specifically the wavelength is 1270 nm. Therefore the correct upstream wavelength for 10G-EPON is 1270 nm.