Huawei Updated H12-891_V1.0 Exam Questions and Answers by abu

Understanding DSCP & Assured Forwarding (AF) Classes

DSCP (Differentiated Services Code Point) is used for QoS (Quality of Service) classification in IP packet headers.

Assured Forwarding (AF) classes provide four traffic classes (AF1x, AF2x, AF3x, AF4x).

Each AF class has three drop precedence levels (Low = 1, Medium = 2, High = 3).

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Analysis of Options:

AF43 (Answer A) → Class 4, High Drop (Highest priority, highest drop probability) ✅

AF10 (Answer B) → Class 1, Low Drop (Lowest priority, lowest drop probability) ❌

AF12 (Answer C) → Class 1, Medium Drop Probability ❌

AF11 (Answer D) → Class 1, Low Drop Probability ❌

Why AF43?

Highest priority traffic within AF Class 4.

Highest drop probability (x3) means packets are dropped first under congestion.

Used for premium but non-essential services (e.g., bulk data transfer, backups).

✅ Reference: Huawei HCIE-Datacom Guide – QoS & DSCP Marking

Understanding NETCONF <config> Operation Attributes

???? What is NETCONF?

NETCONF (Network Configuration Protocol) is an IETF-standardized protocol for network automation.

Uses XML-based configuration transactions with <config> operations.

???? Common NETCONF <config> Operation Attributes:

✅ A. create → Adds new data but fails if it already exists.✅ B. delete → Removes the specified data from the configuration datastore.✅ C. merge → Updates existing data or creates it if it does not exist.

❌ D. remove (Incorrect Choice)

NETCONF does not support remove as an operation.

delete is the correct operation for removing data.

Why is the Answer A, B, C?

✅ NETCONF supports create, delete, and merge, but NOT remove.

Real-World Application:

SDN Controllers & Network Automation: Uses NETCONF to configure devices dynamically.

Huawei iMaster NCE-WAN: Automates device onboarding and template-based configurations.

✅ Reference: Huawei HCIE-Datacom Guide – NETCONF Protocol and Configuration Operations

Understanding User Authentication Points in a Network

Authentication points can be deployed at different network layers based on security and scalability needs:

✅ Access Layer Authentication:

Ensures high security & granular control (user-level authentication).

Preferred in high-security enterprise networks.

✅ Aggregation or Core Layer Authentication:

Reduces authentication overhead but provides less granular control.

Suitable for large-scale networks where authentication load needs to be balanced.

Analysis of the Answer Choices:

✅ A. Deploying user authentication points at the access layer achieves granular permission management and high network security.

Correct: Provides fine-grained control per user and prevents unauthorized access.

✅ B. Moving user authentication points from the access layer to the aggregation or core layer greatly reduces the number of user authentication points, thereby effectively mitigating the pressure on the AAA server.

Correct: Fewer authentication points mean less load on the AAA server.

✅ C. Deploying user authentication points at the access layer has both advantages and disadvantages when compared to doing so at the aggregation or core layer. Policy association can be applied if user authentication points are deployed at the access layer.

Correct: Policy-based authentication is best applied at the access layer for granular control.

❌ D. When user authentication points are moved from the access layer to the aggregation layer, MAC address authentication for users may fail.

Incorrect: MAC authentication works at both layers, but policy adjustments may be needed.

✅ Reference: Huawei HCIE-Datacom Guide – User Authentication Strategies in Enterprise Networks

Huawei Switch Deployment Methods in CloudCampus

✅ A. DHCP Option 148 – Used for automatic device registration in iMaster NCE-Campus.✅ B. CLI (Command-Line Interface) – Traditional manual configuration method using the command-line interface.✅ C. Web Interface – Web GUI-based configuration for easy management.✅ D. Huawei Registration Center – Cloud-based automatic registration and provisioning for plug-and-play deployment.

Reference from Huawei HCIE-Datacom Documentation:

Huawei CloudCampus Deployment Guide – Device Onboarding Methods

HCIE-Datacom Training Material – Zero-Touch Deployment (ZTP) in CloudCampus