H35-211_V2.5 HCIP-Access V2.5 Questions and Answers

The OLT’s anti–IP-attack (control-plane protection) function identifies and rate-limits abnormal or attack traffic to protect the CPU. It does not block legitimate management protocols such as Telnet/SSH by design. Remote management remains available when sourced from permitted hosts and within configured thresholds; administrators can also use trusted-host/ACL policies if needed.

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).

On Huawei access devices/OLTs, VoIP/H.248 setup typically includes:

In voip view, configure media IP with gateway:

ip address media – e.g., ip address media 10.10.10.10 10.10.10.1.

Configure signaling IP without a gateway parameter:

ip address signaling – e.g., ip address signaling 10.10.10.10.

Add/enter the H.248 interface and apply properties with if-h248 attribute ….

It’s common to reset/enable the MG interface after attribute changes; many guides show reset coldstart (or reset) issued under the H.248 interface to activate the interface.

Authoritative configuration examples show media takes an IP and gateway, but signaling takes only the IP. Therefore, option D (attempting to configure signaling with a gateway parameter) is incorrect. Options A and C match documented syntax and workflow. Option B reflects the documented practice of issuing a reset (often written as reset coldstart) under the H.248 interface to apply/enable, as shown in Huawei-focused configuration guides.

XG-PON (10G GPON) adopts XGEM framing. Compared with GPON’s 12-bit GEM Port-ID, XGEM expands the Port-ID field to 16 bits, increasing the number of logical data flows that can be identified per ONU/OLT and improving service granularity. Hence the correct length is 16 bits.

In GPON Type C dual-attribution protection, the ONU has dual PON connections to two OLT PON ports (or two OLTs). When the protection group is configured to track the OLT’s uplink Ethernet port, a Down state on that uplink is an OLT-side trigger. The OLT initiates the protection action (forces the working/standby role swap via PON protection signaling).

A — Correct behavior: After the OLT triggers protection, the ONU’s working PON interface becomes standby, and the protect interface becomes working.

B — Correct behavior: The OLT monitors and updates the ONU uplink status as part of the protection group state machine.

C — Correct behavior: After inversion, services egress the ONU via the protect PON port toward the OLT, i.e., traffic follows the configured protect path.

D — Incorrect (answer): In this scenario the trigger is the OLT’s uplink Ethernet status, not an ONU-detected failure. Therefore the ONU does not detect the fault nor initiate the switchover; the OLT does.

(Reference: HCIP-Access V2.5 – GPON protection mechanisms; Huawei OLT protection group behavior, Type C dual-homing with uplink-tracking.)

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.

In Huawei IPTV troubleshooting, mosaic/flash/jerky or intermittent picture typically results from packet loss or bit errors. Common causes include: optical power near the receiver sensitivity threshold causing FEC/BER spikes (A); loss of I-frames (key frames) either in the encoder/compression stage (B) or due to line transmission loss/jitter (D); and device rate-limit (CAR/policing) misconfiguration that drops packets under burst traffic (C). Any of these can yield unstable display.

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.

Huawei eSight supports multiple L3/L2 discovery mechanisms:

Network-segment (subnet) scanning;

ARP-based discovery in broadcast domains;

Routing-table discovery to traverse multi-segment networks.

Administrators can configure an exclusion list of subnets/IPs; during discovery, eSight skips any addresses listed there, preventing unwanted polling/Onboarding.

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.

On Huawei OLTs, the service-port is a binding between the user-side access (ONT/port) and a VLAN/GEM channel, and it supports traffic policing (CAR/rate-limit) by referencing a traffic/queue profile. Traffic shaping (buffer-based smoothing, token bucket with queue drain) is provided on ports/queues or GEM/LLID directions, not on the service-port object itself. Therefore, shaping is not performed via the service-port; applying a traffic profile there enforces policing, not shaping.

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.

A rogue ONU that transmits out of schedule or at abnormal optical levels can disrupt upstream time-slotting on the PON, causing collision and interference. This can force other ONUs on the same PON to deregister or flap frequently. Huawei OLTs provide rogue ONU detection/isolation to protect the PON.

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.

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.

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 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.)

IPTV over FTTH relies on multicast control; therefore the essential U2000 template is the IGMP template, which defines IGMP behaviors, program authorization binding, and multicast parameters used by the OLT/ONT. MGC applies to voice (VoIP), and SNMP pertains to NMS communication rather than IPTV service logic; value-added templates are not mandatory for basic IPTV.

Huawei OLTs support ONT replacement without deleting the original service profile by using ONT replace/auto-find mechanisms. The OLT can bind the new ONT (new SN) to the existing ONT configuration template (service-port, VLAN, QoS, multicast profile, etc.), achieving a smooth replacement without manually removing and re-creating the ONT and services. The statement that you must remove the ONT and re-register from scratch is therefore wrong.

Drag & Drop Answer (NGN layers → devices):

Network control layer → Softswitch

Service management layer → OSS system

Edge access layer → MA5800

Core switching layer → Core router

Why:

Softswitch handles call/session control ⇒ control layer.

OSS provides O&M/service management ⇒ service management layer.

MA5800 is an OLT/access device ⇒ edge access layer.

Core router provides backbone forwarding ⇒ core switching layer.

Huawei Anti-MAC-Spoofing binds the source MAC to the service flow/port to prevent address forgery. It is functionally exclusive with certain per-VLAN MAC check features (e.g., WMAC, SC, PPPoe-SMAC) to avoid conflicting validation logic. For IPoE users with fixed IP, operators typically configure static bindings/entries so that address and access policies remain consistent.

Option D is wrong: disabling Anti-MAC-Spoofing and removing fixed entries can affect service behavior; if forwarding is interrupted, that does impact user service—so the statement is self-contradictory and incorrect.

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 SIP, each proxy/server that forwards a request prepends its own address to the top of the Via header list. Therefore, as A’s INVITE traverses C, then D, then E, server E adds its Via at the top last, followed by D, then C below it. The message that reaches user B shows the Via stack (top→bottom) as E → D → C, which corresponds to option C. RFC 3261 states that the server transport uses “the value of the top Via header field” to determine response routing, confirming that the most recent hop is at the top

XGS-PON downstream line rate is ~10 Gbit/s. When 12 terminals share a PON tree concurrently, the rough per-terminal share is 10,000 Mbit/s ÷ 12 ≈ 833 Mbit/s, commonly expressed as “about 800 Mbit/s.” This aligns with planning examples in HCIP-Access where downstream concurrency on XGS-PON is calculated by dividing the port rate by the number of active ONUs/APs on the splitter.

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.

In an H.248 (Megaco) control model, the MGC is the controller that issues provisioning/connection-control commands such as Add, Modify, Subtract, AuditValue, AuditCapabilities to the MG. The MG (Media Gateway) can initiate only specific messages toward the MGC to announce state changes or report detected events—namely ServiceChange (to indicate restart, failure, availability changes, etc.) and Notify (to report observed events collected per event descriptor). Therefore, among the listed options, the commands that the MG itself can send are ServiceChange and Notify.

For IP-based discovery, eSight relies on Layer-3 reachability and SNMP/ICMP. Being on the same subnet is not required; that condition applies to broadcast/ARP discovery. Required conditions include proper permissions, IP connectivity, and aligned SNMP parameters.

B is incorrect: NCE deployment options (on-premises, private cloud, public cloud) are determined by service and architecture needs, not by which vendor provides the physical devices.

D is incorrect: Deployment duration varies with hardware platforms, virtualization stacks, and software environments; it is not the same across scenarios.

A and C are correct: NCE exposes NBIs for OSS integration and operates at the analysis/control layer to collect, analyze, and predict issues using big-data/AI capabilities.

At Layer 2, Huawei switches use HGMP/IGMP-Snooping mechanisms to listen to IGMP reports and constrain multicast forwarding to interested ports, preventing broadcast-like flooding. PIM-SM/DM and IGMP-proxy are Layer-3 multicast control/relay functions, not L2 forwarding control.

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.

In access networks, Huawei recommends prioritizing real-time voice (VoIP) traffic with the highest forwarding priority (typically EF, 802.1p 5) to ensure low latency and jitter. IPTV/video is generally next (AF classes), while gaming and general Internet browsing are treated lower than voice. Therefore, VOIP receives the top priority to protect call quality under congestion.