Pass H35-211_V2.5 Exam Guide

Ethernet VLAN identifiers provide a practical limit of about 4K per broadcast domain. As user counts and services grow toward this boundary, Huawei recommends dual-layer VLAN (QinQ) to extend scale and maintain service isolation. Hence the planning threshold is ~4K.

Type C dual-homing provides device-level protection with two OLTs; when one OLT/uplink fails, services switch to the peer OLT. In single-homing, ONUs are associated with only one OLT; therefore an OLT failure interrupts services (C). Single-homing has simpler networking and management than dual-homing (D). It does not offer switchover to another OLT (so B is incorrect), and the “important-service” positioning in A is typically applied to dual-homing scenarios that require the highest availability.

Huawei multicast guidance stresses IGMP version compatibility: devices running an earlier version must interoperate only with hosts using the same or earlier version, otherwise v3 messages may not be processed. In Huawei’s multicast feature guidance for access devices (OLT side vs. user side), the behavior documented is that when the device is operating in IGMPv2, IGMPv3 Report messages from terminals are not processed—interoperation is restored only after the terminal/device side is downgraded to v2 (often driven by periodic queries that induce hosts to respond in v2). This maps operationally to dropping unsolicited IGMPv3 Reports when the OLT is fixed to v2. Huawei also recommends ensuring the device runs an IGMP version the same as or later than member hosts to avoid such loss. Therefore, with OLT fixed at v2, an incoming v3 Join is discarded.

Type B protection (OLT-side + feeder protection via 2×2 optical splitter) is designed for automatic protection switching (APS) upon detecting faults such as LOS/LOF on the working port or feeder. The system automatically switches to the standby PON port/feeder without manual intervention (manual cutover is optional but not required for protection).

(Reference: HCIP-Access V2.5 – GPON Type A/B/C protection definitions, trigger conditions, and APS behavior.)