H35-211_V2.5 Exam Dumps - HCIP-Access V2.5

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.

In campus/access QoS planning on Huawei devices, queue scheduling commonly supports RR, WRR/DRR, and (optionally) strict-priority. WRR (Weighted Round Robin) assigns larger weights to high-priority queues so they receive more transmission opportunities and bandwidth than lower-priority queues while still serving all queues. Therefore, when ensuring better treatment for high-priority services under round-robin–type scheduling, WRR is the recommended choice.

In Huawei QoS processing, traffic classification on access devices/OLTs can match Layer-3 and Layer-2 priority indicators and MPLS labels. Common match fields include IP DSCP (or IP precedence in the ToS byte), MPLS EXP, and IEEE 802.1p CoS carried in VLAN tags. These fields are used to place packets into scheduling/queuing behaviors and policing profiles.

Live TV uses multicast, while VOD uses unicast. If VOD works but live TV is a black screen, typical causes are multicast service-path/config mismatches or priority starvation for multicast control/traffic:

C: If the ONU uses different VLANs for VOD and live but the OLT has only one video service flow, multicast frames will not match the correct service-port, causing black screen.

D: A low-priority traffic profile for multicast join/report or stream on the OLT uplink may drop IGMP joins or multicast packets under load, resulting in black screen while unicast VOD still passes.

Queue scheduling choices such as PQ or DWRR (A/B) are generic congestion schemes; by themselves they are not direct root causes of a live-only black screen unless mis-classified, whereas C and D are recognized multicast-specific fault points.

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).

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 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.

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.