H12-891_V1.0 Exam Dumps - Huawei HCIE-Datacom Questions and Answers

Comprehensive and Detailed In-Depth Explanation:

Blackhole MAC address configuration is a security feature that helps protect a network from MAC address spoofing or attacks involving untrusted MAC addresses. When you configure a MAC address as ablackhole MAC address, any packet received with that address as the source or destination will be immediately discarded by the device.

This feature is useful in scenarios where certain MAC addresses are identified as malicious or untrusted. By adding these MAC addresses to the blackhole list, the device effectively blocks communication involving these addresses, thereby mitigating security risks.

Huawei Open Programmability System (OPS) is a programmable network architecture that uses RESTful APIs. In RESTful operations:

GET → Retrieve data

PUT → Configure/replace the value of a managed object

POST → Create new resources or perform non-idempotent operations

PATCH → Partially update a resource

When configuring or updating the value of a managed object (fully replacing it), PUT is the correct method.

Exact Extract – Huawei OPS and RESTful API Guide:

“The PUT method is used to configure the value of a managed object, replacing the entire object if it exists.”

The command port-isolate enable is used on Huawei switches to completely isolate traffic at both Layer 2 and Layer 3 between different interfaces within the same VLAN. This isolation prevents any communication between isolated ports—even if they belong to the same subnet or VLAN—making it a critical security feature in multi-tenant environments.

Usage Context:

Often used in shared service or hotel network scenarios.

Can be applied in access port configurations.

Does not require additional VLAN creation or private VLAN features.

Huawei Datacom Reference:

"To completely isolate Layer 2 and Layer 3 communication between interfaces in the same VLAN, run the port-isolate enable command under the interface view."

(Source: HCIE-Datacom Study Guide V3.0 – Chapter: VLAN & Security Technologies, Section: Port Isolation)

Comprehensive and Detailed Explanation:

On-premise moderefers to deploying theHuawei iMaster NCE-Campus controllerwithin the enterprise network instead of using a cloud-based solution.

✔Best suited forsmall and midsize campus networksthat require:

Greater control over data security

Local network automation

No reliance on cloud connectivity

Sinceon-premise mode is recommended for small and midsize campus networks, the statement isTRUE.

????Reference:Huawei HCIE Datacom – iMaster NCE Deployment Modes

Understanding Jinja2 Templates in Huawei SSP Packages

????What is Jinja2?

Jinja2 is atemplating engineused inHuawei SSP (Smart Script Package) automation.

It allowsdynamic configuration generationbased on variables and logic.

????Jinja2 Syntax Basics:

✅{% ... %}→ Used forcontrol structureslike loops and conditions.

✅{{ ... }}→ Used forvariable placeholders.

Example of a Jinja2 Template Using {% ... %} for a Loop:

{% for interface in interfaces %}

interface {{ interface.name }}

description {{ interface.description }}

{% endfor %}

????This template dynamically generates interface configurationsbased on a list of interfaces.

Why is the Answer TRUE?

✅{% ... %} is used for control structures in Jinja2 templates(e.g., loops, if-else statements).

✅Jinja2 templates are widely used in SSP for Huawei network automation.

Real-World Application:

Automated Network Configuration:Uses Jinja2 inHuawei SSP automation scripts.

Data Center & SDN Automation:Dynamically generatesVXLAN, BGP, and OSPF configurations.

✅Reference:Huawei HCIE-Datacom Guide – Jinja2 Templates in SSP Packages

Comprehensive and Detailed Explanation:

✔gRPC supports four types of RPCs:

Unary RPC→ Client sendsonerequest, server respondsonce.

Server streaming RPC→ Server sendsmultiple responses.

Client streaming RPC→ Client sendsmultiple requests.

Bidirectional streaming RPC→Bothsides exchange multiple messages.

✔Why B and C Are Incorrect:

❌(B) Incorrect→ The method rpc dataPublish(stream serviceArgs) returns(stream serviceArgs) {} violates gRPC syntax.

❌(C) Incorrect→ rpc stream LotsOfGreetings(HelloRequest) returns (HelloResponse) {} containsincorrect stream positioning.

????Reference:Huawei HCIE Datacom – gRPC API and Streaming Mechanisms

When Spanning Tree Protocol (STP) is not enabled on a network, loops can occur in Layer 2 Ethernet networks, leading to various network issues. STP is designed to prevent loops by blocking redundant paths, and its absence can cause broadcast storms, MAC address table instability, and resource exhaustion. Let’s analyze each option in the context of Huawei HCIE Datacom documentation and network behavior:

A. A loop alarm is generated on the LAN switch.

This option is incorrect. Huawei switches, as per HCIE Datacom standards, do not automatically generate a specific "loop alarm" unless configured with loop detection features (e.g., Huawei’s Loop Detection Protocol or similar mechanisms). Without STP or loop detection enabled, the switch may not explicitly generate an alarm for a loop; instead, it will exhibit symptoms like broadcast storms or flapping MAC entries. Therefore, this is not a direct symptom of an STP-less loop. Reference: Huawei HCIE Datacom V3.0 Training Materials, Section 4.2 – Spanning Tree Protocol and Loop Prevention.

B. CPU usage is too high.

This option is correct. When a loop occurs without STP, broadcast packets (and sometimes multicast or unknown unicast packets) circulate endlessly in the network. This leads to excessive processing by switches as they handle these packets, resulting in high CPU usage. Huawei switches, as described in HCIE Datacom documentation, can experience CPU overload due to continuous packet forwarding and processing in a looped environment. Reference: Huawei HCIE Datacom V3.0, Chapter 5 – Switch Performance and Loop Management.

C. MAC entries flap.

This option is correct. In a loop without STP, switches continuously receive frames from multiple ports, causing MAC address tables to update repeatedly as the same MAC address appears on different ports. This "flapping" of MAC entries destabilizes the network and can lead to incorrect frame forwarding. Huawei HCIE Datacom emphasizes MAC address table stability as a critical aspect affected by loops, as outlined in Section 4.3 – Ethernet Switching and Loop Mitigation. Reference: Huawei HCIE Datacom V3.0, Section 4.3.

D. Host receives a large number of broadcast packets.

This option is correct. A loop without STP causes broadcast packets to circulate indefinitely, creating a broadcast storm. Hosts connected to the network will receive an overwhelming number of these packets, potentially leading to performance degradation or even network timeouts. This is a well-documented symptom in Huawei HCIE Datacom training, specifically in discussions about loop prevention mechanisms. Reference: Huawei HCIE Datacom V3.0, Chapter 4 – Layer 2 Loop Prevention.

Thus, the correct symptoms of a loop occurring due to the absence of STP include high CPU usage, flapping MAC entries, and hosts receiving a large number of broadcast packets. Option A is incorrect as it requires specific loop detection configuration, which is not implied in the question.

Comprehensive and Detailed In-Depth Explanation:

AnNVE (Network Virtualization Edge) interfaceis responsible for connecting physical or virtual devices to a VXLAN network. It functions as theVTEP (VXLAN Tunnel Endpoint)and supportsencapsulation and decapsulation of VXLAN packets.

Layer 2 VXLAN gateway (D)is used for intra-subnet communication, but theNVE interfaceis the actual point where traffic enters the VXLAN network.

Layer 3 VXLAN gateway (A)is used for inter-subnet communication.

VLANIF interface (C)is used for VLAN-based communication, not directly for VXLAN.

Therefore, theNVE interface (B)is the correct answer as it serves as thetraffic ingress and egress point for the VXLAN network.

Huawei IPsec supports multiple modes for establishing Security Associations (SAs):

A. Template negotiation — Used in IPsec policy templates and dynamic VPNs.

B. IKE auto-negotiation mode — Automatically negotiates parameters via IKE Phase 1/2.

C. Certificate negotiation — IPsec peers can authenticate each other using certificates during IKE negotiation.

D. Manual mode — Static IPsec SAs can be manually configured without IKE, often used in simple or static topologies.

Exact Extract - Huawei Security Configuration Guide (USG Series):

“IPsec SAs can be established manually or dynamically through IKE, including using PSKs or certificates. Template-based approaches simplify large-scale deployment.”