Huawei H35-211_V2.5 - HCIP-Access V2.5

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.”

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.

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).

In HCIP-Access teaching materials, 10G-EPON improves optical budget and FEC efficiency compared with 1G EPON, enabling very high split ratios. While commercial deployments commonly use 1:64 or 1:128 depending on optics class and reach, the maximum (laboratory) split ratio often cited for the technology is 1:256 under favorable conditions.

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).

For IPv4 multicast, the MAC mapping uses 01-00-5E followed by the low-order 23 bits of the multicast IP address. Because an IPv4 multicast address has 28 variable bits (224/4), 5 bits are not mapped to the MAC. Therefore, 2⁵ = 32 distinct multicast IP addresses can map to the same multicast MAC address.

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.

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.)

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.

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.