H35-210-V2-5 Sample Questions & Answers

This statement is false. Downstream traffic in a GPON system is broadcast from the OLT to all ONTs on a PON port. Each ONT filters out the frames not addressed to it based on the GEM Port ID. There are no collisions in the downstream direction. Dynamic Bandwidth Allocation (DBA) is used exclusively for managing upstream traffic, where multiple ONTs share the same fiber and must transmit in assigned time slots (TDMA - Time Division Multiple Access) to avoid collisions.

To achieve the goal of transparently carrying the customer's internal VLANs (C-VLANs 10 and 20) within the service provider's S-VLAN 500, a QinQ or VLAN stacking configuration is required. On the Huawei MA5800, this is achieved by defining a service-port that specifies which user VLANs (user-vlan 10 20) are to be accepted and then stacks the provider's port VLAN (port-vlan 500) on top of them. The vlan-stacking keyword enables this double-tagging functionality. VLAN translation would replace the customer's VLANs, not transport them transparently. Transparent mode would pass the C-VLANs but wouldn't add the necessary S-VLAN for provider network transport. A simple trunk port is not sufficient for the provider-level encapsulation required.

The primary purpose of MVR is to efficiently distribute multicast streams across multiple VLANs. A single multicast VLAN is configured to carry the IPTV streams from the source. Other user VLANs are then configured as MVR receiver VLANs. This allows users in, for example, VLAN 100, VLAN 101, and VLAN 102 to send IGMP join requests and receive the multicast stream from the dedicated multicast VLAN (e.g., VLAN 999), without requiring the multicast router to replicate the stream into each individual user VLAN. This conserves bandwidth and simplifies configuration.

The original network is /24. To create subnets, we need to borrow bits from the host portion. To get at least four subnets, we need to borrow 'n' bits such that 2^n >= 4. Borrowing 2 bits (n=2) gives exactly 2^2 = 4 subnets. Borrowing 2 bits from the host portion of a /24 network results in a new subnet mask of /26. A /26 mask in binary is 11111111.11111111.11111111.11000000. Converting the last octet (11000000) to decimal gives 128 + 64 = 192. Therefore, the correct subnet mask is 255.255.255.192.

The FCAPS model defines five functional areas of network management. The 'Configuration' component is responsible for gathering and storing device configurations, provisioning new devices and services, and tracking inventory. Therefore, provisioning VLANs and maintaining a device inventory are core configuration management tasks. Monitoring CPU/memory is part of 'Performance' management. Tracking bandwidth for billing is part of 'Accounting' management. Detecting link failures is part of 'Fault' management.

The GPON standards define several power classes for optics. Class B+ is one of the most common. It specifies a transmit power range at the OLT of +1.5 dBm to +5 dBm and a minimum receiver sensitivity at the ONT of -28 dBm. This provides a total link budget of at least 29.5 dB (1.5 - (-28)), which must account for all losses from fiber, splitters, connectors, and splices, plus a system margin.

FTTH (Fiber to the Home) is the architecture where the optical fiber runs all the way to the individual residence or living space, terminating at an ONT inside the home. This eliminates the use of copper cabling for the final drop, which is the primary bottleneck in other FTTx models. FTTC terminates fiber at a street cabinet, using copper (VDSL) for the last leg. FTTB terminates fiber in a building's basement or communications room, using Ethernet or copper to reach individual apartments. FTTN is the furthest, terminating at a neighborhood node.

The symptoms described (choppy audio, dropped words) are classic signs of high jitter and packet loss, which are critical for real-time protocols like VoIP. Since the HSI service (which uses TCP and is less sensitive to jitter) is working fine, it indicates that the underlying connection is stable but that the sensitive VoIP (RTP) packets are being delayed or dropped when competing with bulk data traffic. The most direct cause for this is the lack of QoS policies to prioritize the VoIP traffic, giving it preferential treatment through the network. While codec choice affects quality and NAT can cause signaling problems, the described symptoms in the presence of working data service point directly to a QoS issue.

To enable GPON and XG-PON to coexist on the same fiber infrastructure, a Wavelength Division Multiplexing (WDM) device is required. Specifically, a WDM1r is used. It combines the GPON wavelengths (1490nm down/1310nm up) with the XG-PON wavelengths (1577nm down/1270nm up) at the OLT side and separates them at the ONT side. This allows both services to operate simultaneously on the same ODN without interfering with each other. A simple splitter is wavelength-agnostic and cannot separate the services. An amplifier boosts signal strength but does not manage wavelengths.

The fundamental difference lies in the direction of the resolution. ARP (Address Resolution Protocol) is used when a device knows the destination IP address (Layer 3) but needs to find the corresponding MAC address (Layer 2) to build the Ethernet frame for local delivery. In contrast, RARP (Reverse Address Resolution Protocol), which is now largely obsolete and replaced by BOOTP/DHCP, was used by a diskless workstation that knew its own MAC address but needed to discover its assigned IP address from a server.