Pass the Huawei HCIP-Access H35-211_V2.5 Questions and answers with ValidTests

For IPv4 multicast, the destination MAC is derived by mapping the lower 23 bits of the multicast IP address into the OUI 01-00-5E. The 4th MAC byte is the lower 7 bits of the IP’s second octet (so it ranges 00–7F), and the 5th and 6th MAC bytes are the third and fourth IP octets directly:

Multicast OUI: 01-00-5E

IP: 227.120.1.32

2nd octet = 120 (0x78). Its lower 7 bits are still 0x78 (since the MSB is 0).

3rd octet = 1 (0x01)

4th octet = 32 (0x20)

Therefore the MAC is 01-00-5E-78-01-20 → option C.

(This mapping aligns with standard IPv4 multicast-to-Ethernet rules described in Huawei’s multicast overview sections in HCIP-Access materials and Huawei OLT product guides.)

GPON (per ITU-T G.984.x and Huawei OLT specifications) provides a downstream line rate of ~2.488 Gbit/s, commonly denoted as 2.5 Gbit/s, and an upstream rate of ~1.244 Gbit/s (1.25 Gbit/s). Therefore, the downstream effective bandwidth option that matches GPON is 2.5 Gbit/s.

In GPON protection schemes, Type B (dual-homing to the same OLT) provides redundancy by using two PON ports on the same OLT (working/standby) and a redundant feeder path via a 2×N splitter or equivalent ODN design. Thus, the protection covers the OLT PON interfaces and the feeder fiber segment. It does not provide protection for the branch (distribution) fibers from the splitter to the ONUs, and it does not involve dual OLTs—that is the scope of Type C.

In Type C single-attribution protection, two PON ports form a protection pair to one ONU/ODN, but only one path is active at a time.

B — Correct: Protection groups operate in active/standby mode; only one OLT-side PON port forwards user traffic at any moment.

A — Not necessarily correct: A branch fiber break local to one path can trigger switchover, but describing it as “the OLT work port becomes standby” is imprecise; the group performs role inversion based on configured triggers and signaling, not solely by OLT port state wording.

C — Not always: Uplink failure triggers switchover only if the protection group is explicitly configured to track the uplink Ethernet port; it is not an unconditional behavior.

D — Misleading: While service entries for the ONU remain consistent from a user perspective, additional protection-group configuration is required on the OLT; thus it is not “completely identical” to a non-protected setup.

(Reference: HCIP-Access V2.5 – Type C single-homing protection architecture, active/standby forwarding, and optional uplink-tracking triggers.)

In FTTB/C voice access with SIP, typical “off-hook but no tone/voice” faults are caused by signaling/control path or device status issues: abnormal MG (Media Gateway/H.248/SIP) interface state on the ONU, unreachable routing between ONU and IMS/softswitch, or a voice server outage. These directly prevent registration, call setup, or media negotiation, resulting in no tone or no audio.

Generic “upper-layer packet loss” on the OLT uplink is not a standard, deterministic root cause specifically for off-hook immediate sound failure; minor loss does not inherently suppress locally generated tones and is not listed as a primary cause in Huawei voice troubleshooting guidance.

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 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.

IGMP is the host-side membership protocol: the first-hop router (querier) uses IGMP Queries/Reports/Leaves to manage host participation in multicast groups and to ensure forwarding state reflects receiver interest. PIM-DM/PIM-SM build distribution trees between routers, and MSDP shares source information between PIM-SM domains—they are not used by hosts.

A mismatch between the service-profile’s user-port configuration and the ONT’s actual port capacity does not disable all services. Ports beyond the ONT’s capability remain inactive/unused, while valid ports with correct service bindings continue to work. Service availability depends on the consistency of applied profiles and actual hardware resources, not on a complete shutdown.

A (True): Huawei multicast configuration defaults commonly allow a user to watch up to 8 programs simultaneously unless overridden (e.g., max-program-num default 8 in multicast/VLAN views and controllable multicast profile).

B (True): On Huawei access devices, IGMP Reports from users are processed by the line card (board) logic/CPU as part of IGMP Snooping/controllable multicast handling to build forwarding entries. (See Huawei IGMP Snooping/Proxy architecture descriptions.)

C (Incorrect): IGMP Snooping is a Layer 2 function, but IGMP Proxy is a Layer 3 function (runs on a gateway to originate Queries and proxy membership upstream). Grouping them together as “Layer 2 global parameters” is incorrect. Huawei documentation distinguishes IGMP Snooping (L2) from IGMP Proxy (L3).

D (True in practice): When automatic matching is not used, multicast program groups/channels must be configured so that user joins map to provisioned program entries (consistent with Huawei controllable multicast/BTV configuration workflows).