Huawei H35-211_V2.5 HCIP-Access V2.5 Exam Practice Test

Right. The SIP Max-Forwards header limits how many SIP elements a request can traverse. Each proxy decrements the value by one; when it reaches zero, the message must not be forwarded, preventing infinite loops and yielding responses like 483 (Too Many Hops). RFC 3261 (Sections 8.1.1.6, 16.6, 20.22) defines this behavior; later work further discusses loop mitigation

In 10G-EPON (IEEE 802.3av), the wavelength plan uses 1577 nm downstream and 1270 nm upstream. The 1270 nm upstream is used in both asymmetric and symmetric 10G-EPON profiles.

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.

This statement is wrong. In U2000, network elements (NEs) can be added by multiple methods, including batch addition/import and automatic discovery, not just one-by-one during a live access session. U2000 supports template-based onboarding and batch operations to improve efficiency for large-scale deployments.

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.)

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.”

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.

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.

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.

Type B provides redundancy with two OLT PON ports on the same OLT and two feeder (backbone) fibers to the ODN. Therefore it protects the PON ports and the backbone/feeder path. It does not protect the OLT itself (still a single OLT) and does not protect the ONU branch fibers.

GPON specifies data encryption (commonly AES-128) on downstream traffic so that one ONU cannot eavesdrop another’s data on the shared PON. This cryptographic protection is the standard, practical method to prevent monitoring on GPON access networks; the other options are operational workarounds, not normal GPON security mechanisms.

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.

According to IEEE 802.3av wavelength planning adopted by Huawei 10G-EPON, downstream uses 1577 nm and 10G upstream uses 1270 nm. In asymmetric coexistence, 1G-EPON upstream uses 1310 nm, but for 10G-EPON upstream specifically the wavelength is 1270 nm. Therefore the correct upstream wavelength for 10G-EPON is 1270 nm.

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 Huawei’s QoS theory (aligned with IETF), the recognized service models are Best Effort, Integrated Services (IntServ), and Differentiated Services (DiffServ). FIFO is a queueing discipline (scheduling method) rather than a service model. FIFO simply forwards packets in arrival order without classification or guarantees, and while it can be used within Best Effort, it is not itself a service model.

With ONT Zero-Touch Provisioning (ZTP) enabled on eSight, newly discovered ONTs can be automatically identified and provisioned by pushing service templates from eSight. This removes the need for advance (preset) service configuration on the OLT during incremental onboarding; the OLT simply accepts the provisioning delivered by eSight.

IPv4 multicast (historically “Class D”) occupies the address block 224.0.0.0 through 239.255.255.255. Any upper bound of 238.255.255.255 is incorrect because it excludes the full 239/8 administratively scoped range. This is standardized in the IANA IPv4 Multicast Address Space registry and reflected in foundational multicast specifications.

Huawei GPON implements hierarchical traffic control. CAR (Committed Access Rate) can be applied at multiple layers: GEM-port level (GEM-CAR), per-flow (Flow-CAR), and T-CONT level (T-CONT-CAR) for upstream bandwidth policing/shaping and guaranteeing QoS. GEM mapping is a classification/association mechanism (service → GEM/T-CONT) rather than a traffic-control action, so it is not a CAR measure.

When other ONUs on the same PON port can register but one ONU cannot, troubleshooting focuses on the individual ONU or its drop fiber. Valid possible causes include: ONU not powered, fiber/connector issues, password/SN mismatch, or faulty ONU hardware. Since hardware failure of that specific ONU is one of the recognized possible causes, the statement is true.

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 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.

IEEE 802.3av (10G-EPON) explicitly enables coexistence of 1G-EPON and 10G-EPON on the same outside plant (ODN) by separating downstream wavelengths (1G ~1480–1500 nm vs 10G ~1575–1580 nm) and using dual-rate TDMA in the upstream (10G uses 1260–1280 nm within the broader 1G band). This wavelength plan and OLT capabilities allow operators to reuse existing ODN and achieve a smooth upgrade via WDM overlays at the OLT. Industry and standards materials emphasize this approach for incremental migration.

An Ethernet port protection group is a 1:1 protection mechanism that improves reliability through active/standby switching. It does not aggregate bandwidth—the standby port does not forward traffic unless a switchover occurs. If increased bandwidth is required, technologies such as LACP are used instead.

For ONT zero-touch on eSight/iMaster NCE-Campus, the prerequisite is that the OLT is onboarded and provisioned (communication parameters, northbound credentials, templates) so that discovered ONTs can inherit policies and be auto-activated. During incremental OLT configuration, eSight does push/update the OLT’s configuration (templates, profiles, authentication rules). Saying “do not provision OLT” is therefore false.

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.

WRED (weighted early drop) uses lower and upper thresholds to determine a probabilistic drop curve; the drop probability scales with the average queue length between these thresholds—therefore D is correct.

A is incorrect because early dropping inevitably affects services to some extent; it’s designed to trade small, controlled loss for stability.

B is incorrect; devices use early drop before buffers fill, and when full, tail drop still applies—both mechanisms coexist.

C is imprecise in Huawei’s terminology; early drop begins when the average queue depth crosses the lower threshold and increases up to the upper threshold, not simply “before a preset threshold” without that two-threshold relationship.

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).

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).

This is wrong. A PON port LED not green may indicate several states—not only a hardware fault. It can mean the port is administratively shutdown, no ONUs are registered, or the port is in an alarm or idle state depending on the LED color and blinking pattern. Fault requires correlation with alarms and performance counters in U2000, not LED color alone.

The ONT details pane in eSight displays access-port attributes (admin/state, type), Ethernet rate/speed/duplex, and PON optical module telemetry such as temperature and Tx/Rx optical power for condition monitoring and troubleshooting.

For enterprise/private multicast, Huawei adopts the administratively scoped range 239.0.0.0/8 for internal multicast groups. 232/8 is typically used for SSM in public domains, 224/8 contains link-local and well-known groups, and 225/8 is not defined as the preferred private scope.

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.

Huawei access devices apply a deterministic service-flow match order for upstream user packets. VLAN-based matching is attempted first. If no specific service flow matches and TLS (Transparent LAN Service) is configured, the system falls back to the TLS service flow as the default L2 transparent handling for that port/user, ensuring service continuity without explicit per-VLAN bindings.

The statement is wrong. SIP explicitly allows several header fields to appear multiple times within a request or response—for example, Via (one per hop), Route, Record-Route, and Contact may legitimately occur more than once. This is fundamental to SIP routing behavior, where each proxy appends a new Via entry. RFC 3261 explains processing based on the top Via among potentially multiple Via headers, which directly contradicts the claim that “a single information value never appears multiple times

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