Huawei H31-341_V2.5 HCIP-Transmission V2.5 Exam Practice Test

The OTUk_LOM (Loss of Multiframe) alarm indicates a framing alignment issue and is generated when the Out Of Multiframe (OOM) state persists for at least 3 milliseconds. This rapid alarm triggering helps detect synchronization failures quickly, allowing prompt response to maintain network stability. HCIP-Transmission details this alarm behavior within OTN frame monitoring functions, highlighting the critical role of frame alignment in maintaining signal integrity across optical networks.

In burst mode, an OTUk_DEG alarm is triggered when bit errors cause signal degradation, even if the error count threshold isn’t crossed.

In burst mode, the alarm also occurs if the number of bit errors within the detection window exceeds the configured threshold.

The RDU9 board is used for demultiplexing optical signals; however, it cannot dynamically demultiplex any wavelength to any port. Dynamic demultiplexing requires advanced ROADMs or wavelength selective switches capable of flexible mapping. The RDU9 has limited fixed demultiplexing functions and does not support arbitrary wavelength-to-port assignments. Therefore, the statement that it can dynamically demultiplex any wavelength to any port is false. This aligns with HCIP-Transmission technical references highlighting the capabilities and limitations of different demultiplexing hardware modules.

For an OA system, the lower threshold of receive optical power of a line board with an APD receiver or the WDM side of an OTU board is the optical module’s receiver sensitivity plus 3 dB, not 5 dB. The 5 dB margin applies mainly to PIN receivers. This distinction is critical because APDs have higher sensitivity and thus require a smaller margin to avoid false alarms or unnecessary protection switching. HCIP-Transmission clearly differentiates these thresholds to ensure proper optical power management and alarm settings in the network.

An IP subnet mask of 27 bits means 32 - 27 = 5 bits are left for host addresses. The number of hosts per subnet is 2^5 - 2 = 30. The subtraction of 2 accounts for the network address and broadcast address, which cannot be assigned to hosts. This calculation is fundamental in IP subnetting and is widely used in network design to allocate IP address ranges efficiently. HCIP-Transmission materials include these principles as part of the networking fundamentals necessary for transmission network engineers.

QPSK uses four phase states, not two. Statement B incorrectly says it assigns two possible phase values, which describes BPSK, not QPSK. QPSK effectively doubles the bits per symbol compared to BPSK, reducing baud rate while maintaining data rate, but with four distinct phases.

In the OTN hierarchy, the OTUCn layer provides digital section functions (framing, section monitoring, forward error correction), and the ODUCn layer provides the digital path (channel) functions, so together they implement the digital section and channel layers.

The ODUk SNCP service defines three protection subtypes:

SNC (Subnetwork Connection)

ISNC (Inverse SNC)

SISNC (Simultaneous Inverse SNC)

The fixed attenuator is usually configured at the receive end, not the transmit end, to prevent the optical power at the receive end of an OTU (Optical Transport Unit) board from being excessively high. High optical power at the receiver can cause signal distortion or damage the receiver module. Configuring the attenuator at the receive end ensures that the incoming signal power is within the optimal sensitivity range of the receiver. Configuring attenuators at the transmit end is generally ineffective because it reduces power output before transmission, potentially reducing reach. This approach aligns with HCIP-Transmission best practices for optical power management and receiver protection.

The egress node checks received CV or FFD packets over any 3-second window when the ingress interval is 1 s (i.e., at three times the transmission interval).

Static LAGs use manual configuration and do not require LACP; LACP is only needed for dynamic link aggregation groups.

The statement that the value of FAS (Frame Alignment Signal) changes dynamically with different signals is false. The FAS is a fixed sequence placed at the start of the OTN frame structure to enable frame synchronization. It does not change dynamically, as its fixed pattern is crucial for reliable frame alignment and error detection. OTUk_LOF (Loss of Frame) alarms are generated when FAS framing fails, indicating synchronization loss. HCIP-Transmission stresses the fixed nature of FAS for consistent framing and alignment across the OTN network layers.

R_LOS, R_LOF, R_OOF, and MUT_LOS all indicate loss of signal or framing, which directly interrupts service delivery.

The EDFA (Erbium-Doped Fiber Amplifier) amplifies optical signals but also introduces Amplified Spontaneous Emission (ASE) noise, making it the primary noise source in optical transmission systems.

The Multiframe Alignment Signal (MFAS) is specifically defined to provide alignment across multiple OTUk/ODUk frames when overhead bytes span those frames, so it must be used for multiframe alignment.

A TTI mismatch in the PM layer generates TTI and TIM alarms but does not constitute a loss of frame alignment, so ODUk_PM_LOF is not reported.

OTUk_LOM (Loss of Multiframe) alarm is generated when frame alignment is lost; however, the statement that it occurs when the Frame Alignment Signal (FAS) is Out of Frame (OOF) for three consecutive milliseconds is false. The actual time threshold differs slightly according to standards and vendor implementations. HCIP-Transmission clarifies these alarm thresholds and conditions to ensure precise timing in fault detection, avoiding false alarms while providing timely notifications for network maintenance.

Among trigger conditions for automatic switching in client 1+1 protection, (A) is false. When SD (Signal Degrade) is disabled, the OTU board does not report an ODUk_PM_DEG alarm as a trigger for switching. Other triggers like the OTU board not detected, OTUk_LOF alarm, and R_LOS alarm reported by OLP or DCP boards are valid triggers for switching. This behavior prevents unnecessary protection switching when SD monitoring is disabled, which helps avoid service disruptions. HCIP-Transmission explains these nuances in protection switching logic to optimize network resilience and reliability.

When a GE (Gigabit Ethernet) service is encapsulated into an OTN frame or an SDH frame structure, the client-side alarms reported are not different; they are consistent regardless of the encapsulation method. This consistency ensures reliable fault detection and service monitoring across different transport technologies. HCIP-Transmission specifies that client alarms depend on service and interface definitions rather than the underlying framing, ensuring seamless interoperability and troubleshooting in multi-protocol environments.

Avalanche photodiode (APD) receivers are commonly used on OTU boards due to their high sensitivity. The input optical power range typically lies between -4 dBm (maximum) and around -28 dBm (minimum). Among the options, -4 dBm is within the acceptable input power range, ensuring the APD operates without saturation or damage. Optical powers too high can saturate the receiver, while too low powers cause poor signal-to-noise ratio. HCIP-Transmission specifies these ranges to ensure optimal receiver performance and avoid optical overload or underpower conditions.

In the described scenario, when the R_LOS alarm is detected on the client side at site A, after alarm processing on the WDM side, a REM_5F alarm is reported downstream at site B. Subsequently, site B reports an R_LOS alarm to its downstream client device, confirming alarm propagation and fault transparency in multi-site transmission. This behavior ensures that faults detected at one point are properly signaled through the network, allowing for coordinated protection and troubleshooting. HCIP-Transmission documents this alarm flow process in WDM site fault management and alarm handling procedures.

In hybrid transmission scenarios involving both 100G-and-beyond and 10G signals, it is recommended that the optical power of 100G signals be higher than that of 10G signals but not exceed the single-wavelength nominal value of the OA board. This ensures the 100G signals, which typically have stricter OSNR and power requirements, maintain adequate quality without causing nonlinear effects or saturation. Proper power balancing between different signal rates prevents performance degradation and interference. HCIP-Transmission guidelines emphasize this approach for hybrid system stability and optimized performance.

With an initial RI1–RI2 difference of 2 dB and a 5 dB threshold, only when the active channel’s loss increases by 7 dB (to 3 dBm) while the standby remains at 8 dBm does the difference reach 5 dB and trigger switching.

Standard mode reduces the number of visible mapping layers by hiding internal ODU-layer paths compared to compatibility mode.

By collapsing internal mappings, standard mode simplifies configuration and lowers maintenance effort.

In standard mode the NMS displays only channel- or physical-port level mappings, with all ODU-layer mappings aggregated at the port view.

The TMB1AST2 board is a specialized optical module used in transmission equipment. According to HCIP-Transmission references, all the statements about this board are correct. (A) The TM1 optical port must be connected to the TMI1 optical port for proper operation. (B) It supports IEEE 1588v2 clock processing, essential for precise time synchronization, and includes OTDR (Optical Time Domain Reflectometer) functions for fiber fault detection and maintenance. (C) When working with DFIU03/DFIU04 boards, the OSC optical port requires an optical module that supports the 1511 nm wavelength to ensure wavelength compatibility. (D) Similarly, when working with DSFIU01/DSFIU02 boards, the TM1/RM1 and TM2/RM2 ports must use optical modules supporting 1511 nm and 1491 nm wavelengths respectively, ensuring correct wavelength assignment for WDM channels. This detailed configuration ensures interoperability and proper system functionality.

The TNG2WSMD09 board is a 9-port wavelength selective multiplexer/demultiplexer for the Super C band and supports optical power adjustment and online optical power detection.

The power difference becomes 6 dB (2 dBm – (–4 dBm) = 6 dB), which exceeds the 5 dB threshold, so protection switching occurs.

In OA-free systems, where no optical amplifiers are used, the lower threshold of the receive optical power of a line board or the WDM side of an OTU board is indeed the optical module’s receiver sensitivity plus 3 dB. This ensures a safety margin for stable signal reception and alarm triggering. Without optical amplifiers, signal levels are more susceptible to attenuation, so maintaining this margin helps prevent degradation due to low optical power. HCIP-Transmission highlights this threshold as a standard parameter for optical power management in non-amplified systems.

The statement that the OA gain can be reduced when expanding 100G channels in a 10G system to meet incident optical power requirements is false. In fact, the single wavelength incident optical power of a 100G system is higher than that of a 10G system, and gain adjustment needs to ensure the 100G channels meet their power requirements without degradation. Reducing OA gain indiscriminately could cause insufficient amplification for 100G signals, impairing performance. HCIP-Transmission specifies careful power management and gain setting to balance multi-rate systems during hybrid transmission expansion.

An inserted ODUk_PM_LCK overhead is transparently forwarded downstream rather than reported or converted into another alarm.

The formula to calculate the OTUk frame rate is: OTUk frame rate = 255 / (239 - k) × STM-N frame rate. Here, "k" represents the OTUk version index, and STM-N is the synchronous transport module rate. This formula derives from the OTN standard, adjusting the frame rate according to the version and allows synchronization with underlying SDH/SONET rates. HCIP-Transmission materials provide this formula for engineers to correctly understand and calculate transmission rates for different OTN layers.

Lower ground resistance indicates better grounding performance because it allows current to be conducted to the ground more quickly and efficiently. Good grounding is essential for equipment protection, system stability, and safety in transmission networks. A low resistance path reduces the risk of electrical shock, equipment damage, and signal interference. HCIP-Transmission underscores the importance of grounding quality as part of overall network infrastructure integrity and reliability, making low ground resistance a key objective in grounding design.

The TNG2M60V board is not a 60-channel multiplexer with VOA for the Super C band; this description is incorrect for that board model.