H12-891_V1.0 Huawei HCIE-Datacom V1.0 Free Practice Exam Questions (2026 Updated)

Comprehensive and Detailed In-Depth Explanation:

The Huawei SD-WAN Solution involves four types of channels to ensure smooth and efficient network operation:

Management Channel (A): Used for managing and monitoring SD-WAN devices. It facilitates communication between the iMaster NCE-Campus controller and SD-WAN devices.

Control Channel (B): Responsible for transmitting control plane information such as routing updates and protocol control messages.

Data Channel (C): Carries actual user data traffic over the SD-WAN network.

Orchestration Channel (D): Used for service orchestration, configuration delivery, and policy management.

All four channels work together to provide comprehensive network management, data transmission, and service orchestration in an SD-WAN environment.

Telemetry Data Collection in Huawei Devices

Telemetry allows real-time streaming of network performance data based on predefined sampling paths. Supported sampling paths include:

✅ A. Interface statistics

Monitors real-time traffic usage, errors, and packet loss on interfaces.

✅ C. CPU information

Tracks CPU utilization and performance metrics.

✅ D. Memory information

Monitors RAM usage and system memory consumption.

Incorrect Answer:

❌ B. Information about the optical module on an interface

Telemetry does not natively support direct optical module monitoring; instead, SNMP or CLI commands like display transceiver are used.

Reference from Huawei HCIE-Datacom Documentation:

Huawei Telemetry Configuration Guide – Supported Sampling Paths

HCIE-Datacom Study Material – Network Performance Monitoring with Telemetry

Understanding the Routing Table Entries on R4

0.0.0.0/0 (Default Route) is installed twice in the routing table.

The NextHop values for the default route:

10.1.24.1 (GigabitEthernet0/0/1)

10.1.34.1 (GigabitEthernet0/0/0)

Cost: Both routes have a metric (Cost) of 10, meaning they are equal-cost routes.

Protocol: ISIS-L1 (Intermediate System to Intermediate System - Level 1) confirms these routes are coming from IS-IS routing.

Flags: D (Dynamic) means these routes were dynamically learned via IS-IS.

Why is Option D Correct?

Since both routes have the same cost (10), they are considered equal-cost default routes.

The router will use both routes in a load-sharing fashion.

The answer is NOT A (Four equal-cost routes) because there are only two default routes, not four.

The answer is NOT B (One default route) because there are two default routes in the table.

The answer is NOT C (Two default routes with different costs) because both routes have the same cost (10).

Real-World Application

Equal-Cost Multi-Path (ECMP): The router can perform load balancing across the two equal-cost paths.

Resilience & Redundancy: If one link fails, the other can take over without re-calculating the entire routing table.

✅ Reference: Huawei HCIE-Datacom Study Guide – IS-IS Routing & ECMP Load Balancing

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 a blackhole 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.

In OSPFv3, each LSA type has a defined flooding scope:

Link-LSA (Type 8)

Advertised only on the local link

Contains router’s link-local address and prefixes

Scope: Within the local link scope ✅

AS-External-LSA (Type 5)

Used to advertise external routes from outside the AS

Flooded across the entire autonomous system, except stub/NSSA areas

Scope: Within an AS ✅

Network-LSA (Type 2)

Generated by the Designated Router (DR)

Describes all routers on a broadcast or NBMA segment

Flooded within the originating area

Scope: Within an area ✅

Correct Mappings:

Link LSA → Within the local link scope

AS-External-LSA → Within an AS

Network-LSA → Within an area

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)

A. The device sends sampled data every second → Correct, since sample interval is 1000ms = 1 second.

B. The subscription mode is static subscription → Correct, as shown by Sub state: PASSIVE. Passive indicates a static subscription.

C. The IP address of the device is 192.168.56.1 → Incorrect — this IP address is the destination (telemetry collector), not the device’s own IP.

D. The subscription name is Sub1 → Correct, as per Sub name : Sub1.

Correct answer: C. The IP address of the device is 192.168.56.1 — this is incorrect because it ' s actually the collector’s IP, not the device ' s.

The free mobility solution in Huawei iMaster NCE-Campus allows:

Centralized policy management via the controller

Security group-based policies, decoupled from IPs/VLANs

Automatic policy delivery, no need to configure repeatedly per device

Dynamic mapping of users and IPs via security group subscriptions

Exact Extract - Huawei iMaster NCE-Campus Solution White Paper:

“Free mobility uses security groups and centralized control to enable consistent policy enforcement, avoiding repetitive configurations and simplifying policy management.”

For OSPF neighbors to reach Full state, they must exchange LSAs (Link State Advertisements) properly and synchronize their databases.

Possible Causes Preventing OSPF from Entering Full State:

✅ A. A link works abnormally

If the physical or Layer 2 link is unstable, OSPF Hello packets may be lost, preventing the Full state.

✅ B. The OSPF network types on both ends of the link are inconsistent

OSPF network types (Broadcast, P2P, NBMA, etc.) must match on both ends.

Example: If one router is P2P and the other is Broadcast, adjacency issues occur.

✅ C. The router IDs of neighbors are the same

Router ID conflicts prevent OSPF adjacencies from forming.

Each router must have a unique Router ID.

✅ D. The OSPF MTU values of interfaces on both ends of the link are different

If MTU settings do not match, OSPF Database Description (DD) packets may be dropped, preventing Full state.

Reference from Huawei HCIE-Datacom Documentation:

Huawei OSPF Configuration Guide – Troubleshooting OSPF Neighbor Issues

HCIE-Datacom Study Material – OSPF Adjacency and Route Synchronization

WRED (Weighted Random Early Detection) helps prevent congestion by randomly discarding packets before buffers are full.

Drop Probability Behavior:

Below lower threshold = 0% drop (packets pass normally).

Between lower & upper threshold = Progressively increasing drop probability.

Above upper threshold = 100% drop (probability = 1).

✅ Reference: Huawei HCIE-Datacom Guide - WRED Mechanism

Comprehensive and Detailed In-Depth Explanation:

In large- and medium-sized campus networks, Multi-mode authentication is commonly used for PCs connected to IP phones. This is because multi-mode authentication allows:

Multiple authentication methods on the same interface, such as MAC address authentication for the IP phone and 802.1X authentication for the PC.

This setup is ideal for scenarios where both devices share a single network port but require different authentication mechanisms.

MAC address authentication (A) and 802.1X authentication (B) individually cannot accommodate both devices efficiently.

Portal authentication (D) is mainly used for guest access and is not practical for IP phone and PC connections.

Comprehensive and Detailed In-Depth Explanation:

When configuring a virtualized campus network on iMaster NCE-Campus, the platform supports automatic delivery of routing policies when connecting to external networks, including the Internet.

This feature ensures that traffic destined for external networks is automatically directed to the appropriate egress points.

The NCE-Campus automatically creates and delivers the default route or specific routes, depending on the network topology and configuration.

This simplifies network management by eliminating the need for manual route configuration on each device.

Therefore, the statement is TRUE.

When VLAN-based MAC address flapping detection is configured, the following actions can be taken:

Alarm sending (generates logs or SNMP traps)

MAC address blocking (blocks specific flapping MAC addresses)

Interface blocking (shuts down or disables the interface temporarily)

Traffic filtering, however, is not an action option directly supported as a response to MAC flapping. Traffic filtering is part of ACL or QoS, not a built-in flapping response.

Exact Extract - Huawei Switching Configuration Guide – MAC Address Management:

“Actions that can be configured upon detection of MAC address flapping include sending alarms, blocking MAC addresses, and blocking interfaces. Traffic filtering is not supported as a direct action.”

In Huawei ' s SRv6 instruction naming system, each letter keyword represents a specific forwarding behavior:

X (Cross): Forwards packets via specified Layer 3 interfaces → ✅

M (MAC): Searches Layer 2 forwarding table for broadcast/multicast, not unicast → ❌

V (VPN): Searches the VPN routing table (VRF) for forwarding → ✅

T (Table): Searches a specific routing table (e.g., user-defined) → ✅

Correct answers: A, C, D

GRE (Generic Routing Encapsulation) supports encapsulation of many protocol types:

Supports IPv4 and IPv6 unicast encapsulation — ✅

Does not support IPv6 broadcast encapsulation. GRE doesn’t natively handle multicast or broadcast IPv6 traffic well — ❌

It is a lightweight tunneling protocol and relatively easy to deploy, placing minimal overhead on devices — ✅

Correct answer: C. GRE can encapsulate IPv6 broadcast packets — is incorrect.

Network migration typically includes the following phases:

Preparation Phase:

Network survey

Migration plan design

Backup

Pre-configuration

Middle Phase (Migration Execution):

On-site monitoring

Migration implementation

Service test (to verify the migration effect)

Post-Migration Phase:

Optimization

Documentation

Final acceptance

Hence, Migration preparation is part of the initial phase, not the middle phase.

Correct answer: A. Migration preparation

In YANG model syntax:

cpu-info can be a list node (✓)

cpu-infos can be a container node (✓)

The sampling path does follow the YANG model hierarchy (✓)

However, the prefix huawei-debug: indicates the YANG module name, not an actual data node. Therefore, debug is not necessarily the top node in the YANG hierarchy — it is a node under the huawei-debug namespace/module.

Exact Extract – Huawei Telemetry and YANG Modeling Guide:

“The format < module-name > : < data-node > is used in telemetry to indicate paths. The actual top-level node may differ from the module name.”

In Huawei’s VXLAN implementation, the typical mapping between VNIs (VXLAN Network Identifiers) and BDs (Bridge Domains) is:

1:1 mapping — each VNI is uniquely associated with a single bridge domain.

This allows proper MAC learning and forwarding in the data plane for isolated tenant traffic.

Other mappings (N:1, 1:N, N:M) may be technically possible but not recommended or supported in most enterprise deployments.

Correct answer: B. 1:1