H35-210-V2-5 Huawei Practice Questions

DHCP snooping is a Layer 2 security feature that validates DHCP messages. It works by classifying switch ports as either trusted or untrusted. Trusted ports are those that connect to legitimate DHCP servers. Untrusted ports connect to end-user devices. The switch will only allow DHCP Offer and DHCP Ack messages from trusted ports, effectively blocking any rogue DHCP servers connected to untrusted ports from responding to client requests. DHCP Relay is for forwarding DHCP requests across subnets, and Dynamic ARP Inspection uses the DHCP snooping binding database to prevent ARP spoofing.

This statement is false. The roles are reversed. G.652D is a standard single-mode fiber that is cost-effective and well-suited for the feeder and distribution segments where cables are laid in straight paths within ducts or aerial deployments. G.657 bend-insensitive fiber is specifically designed to handle tight bends with minimal signal loss, making it ideal for the drop segment and in-building wiring where cables must navigate sharp corners and staples, which is common inside a customer's home (MDU or SFU).

SHDSL (Symmetric High-speed Digital Subscriber Line) is specifically designed to provide symmetric bandwidth, meaning the upstream and downstream speeds are the same. This makes it ideal for business applications like hosting servers, video conferencing, or site-to-site VPNs. Both ADSL2+ (Asymmetric DSL) and VDSL2 (Very-high-bit-rate DSL) are typically asymmetric, providing much higher downstream bandwidth than upstream.

The scenario describes a classic use case for zero-touch provisioning (ZTP). On the Huawei platform, this is achieved by enabling the ONT auto-find feature on the PON port. When a new ONT connects, the OLT discovers it. By pre-configuring a policy that binds the ONT's serial number (or other identifier) to a specific line profile (defining physical layer parameters) and a service profile (defining logical services like VLANs, bandwidth, VoIP), the OLT can automatically apply the full configuration upon successful registration. This completely automates the process, meeting the requirement to minimize manual NOC intervention.

The PPPoE discovery stage follows a four-step process:

1. PADI (PPPoE Active Discovery Initiation): The client broadcasts this packet to discover all available PPPoE servers.
2. PADO (PPPoE Active Discovery Offer): One or more servers reply with a unicast offer to the client.
3. PADR (PPPoE Active Discovery Request): The client selects one server and sends a unicast request to it.
4. PADS (PPPoE Active Discovery Session-confirmation): The selected server confirms the request and provides a Session ID, at which point the PPP session begins.

While sufficient optical power is necessary, it is not the only requirement for successful registration. The GPON standard includes a management protocol called OMCI (ONT Management and Control Interface) for the OLT to manage the ONT. If the ONT is from a non-certified third-party vendor, its OMCI implementation may be incompatible with the Huawei OLT, leading to a failure during the ranging and provisioning process, even with perfect optical levels. A -22 dBm signal is a healthy level, not too high. A rogue ONT would typically cause issues for other ONTs on the same PON port. Incorrect VLAN configuration affects service provisioning after registration, not the ranging process itself.

VDSL2 vectoring works by having the DSLAM calculate and generate anti-phase signals to cancel out the crosstalk between lines. For this to be effective, two key conditions must be met: 1) The VPE must be able to 'see' and process all the lines within a single cable binder group, as these are the lines that significantly interfere with each other. If lines are split across different VPEs or DSLAMs, system-level vectoring is required, which is more complex. 2) The CPE modem must also be vectoring-compliant (G.993.5) to cooperate with the DSLAM in the crosstalk estimation and cancellation process. Annex type and profile matching are important for basic connectivity and speed, but are not the primary requirements for vectoring itself.

The best practice for triple-play service delivery is to use separate VLANs for each service. This allows for logical separation of traffic, enabling distinct QoS policies, security rules, and routing paths for each service type. Binding each service to a specific port (or group of ports) and a unique VLAN ID (e.g., VLAN 100 for HSI, 200 for VoIP, 300 for IPTV) is the standard and most effective method. Using a single VLAN makes QoS differentiation difficult. Using QinQ on the ONT is unnecessary and overly complex for this common residential scenario. Binding all services to a single port would require a managed switch at the customer premise to separate them.

While other options can cause PPPoE issues, the symptom of a correct username/password resulting in an 'Access-Reject' from RADIUS strongly points to a mismatch in the shared secret. The shared secret is used to encrypt the password in the RADIUS Access-Request packet. If the BNG and RADIUS server have different secrets, the server cannot decrypt the password correctly, leading to an authentication failure even if the user typed the correct password. An MTU issue would typically cause problems after the session is established. DHCP Option 82 is unrelated to PPPoE authentication. A faulty RADIUS server would likely affect all users, not just a specific group.

A mechanical connector pair (like an SC or LC connector) introduces a small air gap between the fiber end faces, which causes a strong reflection (Fresnel reflection). This appears as a sharp reflective spike on the OTDR trace. The connector pair also has insertion loss, meaning less light continues down the fiber, resulting in a visible drop in the backscatter signal level immediately after the spike. A fusion splice is non-reflective and shows only a small loss step. A macrobend is also non-reflective and appears as a gradual loss or a localized drop without a spike. The end of the fiber shows a strong reflective peak but is followed by the noise floor, not a continuing backscatter level.