H35-211_V2.5 Huawei HCIP-Access V2.5 Free Practice Exam Questions (2025 Updated)

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.

In IPTV/multicast access scenarios, channel zapping delay is heavily influenced by how fast the network stops forwarding the previous channel’s stream after a user switches. Huawei documents the IGMP Fast Leave/Prompt Leave feature, which enables the access device to immediately prune the old multicast group on receipt of a Leave (without waiting for group-specific queries and timers), thereby reducing the channel change delay and improving perceived switching speed. Option A explicitly disables a helpful pre-join optimization, which would worsen experience; Option C (preview) concerns showing brief previews and is not a primary mechanism for shortening zapping time; Option D is unrelated to performance. Thus, enabling Quick/Fast Leave is the correct action to shorten switching time.

With PITP enabled and Vendor-tag switching allowed, Huawei OLTs support transparent transmission and augmentation: the OLT keeps the user-carried Vendor tag and appends the local Vendor tag (e.g., slot/port/location), ensuring the upstream AAA/BRAS receives both the access-side identity and the OLT’s own location identity. Simply adding only the local tag (A) loses user-side info; forwarding unchanged (B) omits OLT location; discarding (D) contradicts the feature intent.

Per RFC 3261 (SIP), “The CSeq header field of the response MUST equal the CSeq field of the request.” CSeq carries a sequence number and the method, thereby associating a response with the specific request it answers. While Call-ID ties together all messages within the same dialog, it does not identify the specific request/response pairing; CSeq does. Therefore, CSeq is the correct header for correlating a response to the exact request.

According to Huawei HCIP-Access V2.5 learning materials and official Huawei Access Network product documentation, a 10G EPON PONI port supports both EPON (1.25 Gbit/s) and 10G EPON (10 Gbit/s) transmission modes.

These two modes are not combined — they operate on different wavelengths and serve different types of Optical Network Units (ONUs):

EPON uses a 1490 nm wavelength for downstream transmission with a rate of 1.25 Gbit/s.

10G EPON uses a 1577 nm wavelength for downstream transmission with a rate of 10 Gbit/s.

When an OLT (Optical Line Terminal) port supports dual-mode operation, it automatically adapts to the connected ONU type — but it does not aggregate the bandwidth of both technologies. Each ONU communicates using only one rate (either EPON or 10G EPON).

Therefore, the total downstream bandwidth is not the sum of both rates. It depends solely on the ONU’s operational mode.

Hence, the statement is False.

Answer: B

References (from HCIP-Access V2.5 and Huawei Technical Documents):

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

Huawei Access Network 10G EPON Technology White Paper (Huawei Enterprise Documentation Center)

Huawei MA5800/EA5800 Series OLT Product Description – “Dual-Mode EPON/10G EPON PON Ports”

When other ONUs on the same PON port can register but one ONU cannot, troubleshooting focuses on the individual ONU or its drop fiber. Valid possible causes include: ONU not powered, fiber/connector issues, password/SN mismatch, or faulty ONU hardware. Since hardware failure of that specific ONU is one of the recognized possible causes, the statement is true.

Huawei GPON implements hierarchical traffic control. CAR (Committed Access Rate) can be applied at multiple layers: GEM-port level (GEM-CAR), per-flow (Flow-CAR), and T-CONT level (T-CONT-CAR) for upstream bandwidth policing/shaping and guaranteeing QoS. GEM mapping is a classification/association mechanism (service → GEM/T-CONT) rather than a traffic-control action, so it is not a CAR measure.

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.

In IP address discovery mode, eSight does not require L2 same-subnet adjacency; it only requires IP reachability/routing, proper SNMP credentials/alignment, and the operator’s Resource Access permission to poll and add devices. The “same network segment” prerequisite applies to ARP broadcast discovery mode, not to IP address discovery.

A persistently high CPU on the OLT main control board is typically driven by excessive control-plane load or abnormal traffic patterns. Common causes include:

Illegal login attempts generating authentication and logging overhead (A)

Layer-2 loops leading to storms and protocol churn (B)

DoS/scan/attack traffic stressing control/management processing (C)

Rogue/misbehaving ONUs causing frequent state changes, registration flaps, or abnormal report traffic (D)

All listed factors are recognized contributors to elevated CPU on access OLTs.

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).

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.”

Huawei VLAN planning considers overall VLAN scale, user categories and volume, service types (HSI/IPTV/VoIP) and their isolation, uplink/aggregation mode (e.g., QinQ, VXLAN interwork), and device/topology constraints (e.g., OLT slot/board distribution). All listed factors affect VLAN count, tagging scheme, and scalability.

PITP (Port Identification Transparent Transmission) is used on access networks to carry a user’s physical access-location to the upper AAA/BRAS. It has two working forms: P-mode (PPPoE+)—injecting location identifiers into PPPoE discovery—and V-mode (Vendor-tag)—carrying vendor/location tags transparently upstream. The purpose is to let the upper server associate user credentials with access location and, by policy, restrict roaming. Options A, B, D, and E correctly describe these behaviors/terms. Option C is inaccurate as written: PITP itself does not “bind the authentication” or inherently “avoid theft/roaming”; it only delivers location info. Preventing credential theft/roaming is achieved by AAA/BRAS policy that uses the PITP-carried location, not by PITP alone.