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

Understanding the Telemetry Output:

Dest-addr: 192.168.56.1 → The destination IP address is 192.168.56.1. ✅

Dest-name: Dest1 → The destination group name is Dest1. ✅

Protocol: gRPC → Data push uses the gRPC protocol. ✅

Vpn-name: - (empty) → No VPN encapsulation is used. ❌

Incorrect Answer Explanation:

❌ C. " VPN encapsulation is used for data push " → Incorrect!

The Vpn-name field is empty, indicating that VPN encapsulation is NOT enabled for telemetry data transport.

Reference from Huawei HCIE-Datacom Documentation:

Huawei Telemetry Configuration Guide – Destination and Data Push Methods

HCIE-Datacom Study Material – gRPC and Telemetry Data Streaming

Huawei iMaster NCE-Campus Wi-Fi Location-Based Services (LBS) use HTTP/HTTPS to send location data (such as AP association, signal strength, timestamp, etc.) to an external LBS platform.

The standard format for such data exchange is JSON (JavaScript Object Notation).

JSON is lightweight, readable, and widely supported by modern web APIs and platforms.

Other options:

XML: Used in legacy systems, heavier format.

HTML: Used for page rendering, not data transfer.

YAML: Used mainly in configurations, not standard for HTTP APIs.

Correct answer: C. JSON

When selecting core devices for a WAN in enterprise networks, considerations typically include:

Service volume: Ensures the core device can handle expected traffic.

Physical location: Important for latency, redundancy, and network design.

Node quantity: Affects topology, scalability, and routing complexity.

Device naming conventions, however, are purely administrative and do not affect the functional selection of core devices.

Correct answer: A. Device naming conventions

In hot standby (active-active/load balancing) scenarios, Quick Session Backup is critical. This function ensures that session entries are immediately synchronized between firewalls to handle asymmetric traffic (where return traffic goes through a different firewall than the forward traffic).

Without it, the return packet may be dropped due to missing session information on the alternate firewall.

Exact Extract - HCIE-Datacom Security Module:

“When VGMP is in load balancing mode, quick session backup must be enabled to prevent traffic loss due to inconsistent forward and return paths.”

BGP EVPN Route Types in VXLAN:

BGP EVPN Type 2 Route (MAC/IP Advertisement Route)

Used for host reachability advertisement.

Carries MAC and IP address information of endpoints.

Does not carry an IP Prefix field (Type 5 routes handle prefixes).

Correct Explanation of Answer Choices:✅ IP Address (B) is included – Used for host mobility and reachability.✅ L3VNI (C) is included – Used for Layer 3 VXLAN routing.✅ L2VNI (D) is included – Used for Layer 2 VXLAN bridging.❌ IP Prefix (A) is not included in Type 2 routes – It is part of EVPN Type 5 routes for prefix advertisement.

Reference from Huawei HCIE-Datacom Documentation:

Huawei VXLAN BGP EVPN Configuration Guide – Type 2 vs. Type 5 Routes

HCIE-Datacom Training Material – VXLAN Overlay Networks and BGP EVPN

In SRv6 (Segment Routing over IPv6), flavors are extensions to standard SRv6 instructions that define how the Segment Routing Header (SRH) is handled at specific points:

PSP (Penultimate Segment Pop): Instructs the penultimate node to remove the SRH before reaching the last node → ✅

USD (Ultimate Segment Decapsulation): Instructs the final segment to remove the SRH and IPv6 header, exposing the payload → ✅

PSD (Penultimate Segment Decapsulation): Instructs the penultimate node to remove the SRH and deliver the payload → ✅

USP (Ultimate Segment Pop) is not a standard flavor in Huawei SRv6 implementations → ❌

Correct answers: A, B, D

Comprehensive and Detailed In-Depth Explanation:

To support SR-MPLS (Segment Routing over MPLS), OSPF uses Type 10 Opaque LSAs to advertise Segment Routing (SR) capabilities and information.

Type 10 Opaque LSA (B): Used for distributing application-specific information within an OSPF area. In SR-MPLS, it carries the SID/Label mappings and other SR-related information.

Type 7 NSSA External LSA (A): Used to advertise external routes within an NSSA, not related to SR-MPLS.

Type 1 Router LSA (C): Advertises the router’s interfaces and links but does not carry SR-specific information.

Type 2 Network LSA (D): Advertises the links of a broadcast or NBMA network, not used for SR-MPLS.

Therefore, the correct answer is B (Type 10 Opaque LSA), as it enables the advertisement of SR information.

Understanding MPLS Label Retention Modes

In MPLS (Multiprotocol Label Switching), a Label Switching Router (LSR) can operate in one of two label retention modes:

1️⃣ Liberal Label Retention Mode (LLRM)

Stores all labels received from neighbors, even if they are not immediately used.

Advantage: Fast convergence during link failures.

Disadvantage: Consumes more memory & label space.

2️⃣ Conservative Label Retention Mode (CLRM)

Only keeps labels for the best next-hop path.

Advantage: Saves memory & label space.

Disadvantage: Slower convergence when topology changes.

Why are C and D Correct?

✅ C. An LSR reserves all labels distributed by its neighbor.

Correct: In Liberal Mode, the router accepts and stores all labels received, even for non-best paths.

✅ D. The liberal mode requires more memory and label space.

Correct: Since the router keeps all labels, it requires higher memory & storage.

Why are A and B Incorrect?

❌ A. An LSR retains labels from a neighboring LSR only when the neighbor is its next hop.

Incorrect: This describes Conservative Mode, not Liberal Mode.

❌ B. This label retention mode saves memory and label space.

Incorrect: Liberal Mode consumes more memory, not less.

Real-World Application

Liberal Mode is used in large-scale MPLS networks where fast failover is critical.

Conservative Mode is preferred in memory-constrained environments.

✅ Reference: Huawei HCIE-Datacom Study Guide – MPLS Label Retention Modes

BGP EVPN in VXLAN Tunneling

✅ A. MP_REACH_NLRI is used to carry routing information.

MP_REACH_NLRI (Multiprotocol Reachable Network Layer Reachability Information) is used in BGP updates to carry VXLAN reachability information.

✅ B. Several BGP EVPN routes are defined through BGP extension.

BGP EVPN introduces multiple route types, such as Type 2 (MAC/IP Advertisement), Type 3 (Inclusive Multicast), and Type 5 (IP Prefix Advertisement).

✅ D. MP_REACH_NLRI is used to carry the RT.

RT (Route Target) defines route import/export policies in VPN environments.

MP_REACH_NLRI carries the RT attribute in BGP EVPN updates.

❌ Incorrect Answer:

❌ C. MP_REACH_NLRI is used to carry the RD.

Wrong! The Route Distinguisher (RD) is carried inside BGP attributes, but not in MP_REACH_NLRI.

Reference from Huawei HCIE-Datacom Documentation:

Huawei VXLAN BGP EVPN Configuration Guide – BGP EVPN Route Types

HCIE-Datacom Training Material – VXLAN Dynamic Tunnel Establishment

Comprehensive and Detailed In-Depth Explanation:

MACsec (Media Access Control Security) is a security protocol that provides secure communication over Ethernet links. It operates at the MAC layer (Layer 2) and offers the following key security services:

Integrity Check (B): Ensures that data has not been tampered with during transmission.

User Data Encryption (C): Protects data confidentiality by encrypting the payload.

Data Source Authenticity Verification (D): Confirms that the data originates from a legitimate source by using security associations.

Controllability Check (A) is not a service provided by MACsec. The term " controllability " typically relates to network management and configuration control rather than data security. MACsec primarily focuses on protecting data integrity, confidentiality, and authenticity, rather than controlling network elements or configurations.

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.

The incorrect statement is Option C, which says “A site can only belong to only one VPN.” This is false because a single site can belong to multiple VPNs if needed. For example, in some enterprise designs, a site may be part of both the Finance VPN and the Management VPN by configuring multiple routing instances (VRFs) and policies accordingly.

Exact Extract - HCIE-Datacom VPN Technologies Chapter:

“A site may be associated with one or more VPNs, depending on business requirements. This is achieved through VRF and route-target configurations.”

In MPLS VPN, packets are forwarded using two labels:

Outer label (Transport Label) – Used by the MPLS backbone for forwarding.

Inner label (VPN Label) – Used by the egress PE to identify the correct VPN instance.

Explanation of Correct Options:

✅ A. The egress PE sends the data packet to the correct VPN based on the inner label.

The inner label is assigned by the egress PE and determines the final destination VPN instance.

✅ B. The penultimate hop removes the outer label before forwarding the data packet to a peer egress PE.

Penultimate Hop Popping (PHP) occurs when the second-to-last router (P router) removes the outer MPLS label before forwarding to the egress PE.

This reduces the processing overhead on the egress PE.

✅ D. The penultimate-hop device receives a packet with an outer label.

The outer label is used to forward the packet across the MPLS backbone.

Before reaching the egress PE, the penultimate router still has the outer label and processes it.

Incorrect Option:

❌ C. The IP data packet received by the egress LSR is without labels.

This is incorrect because the inner label (VPN label) is still present when the packet reaches the egress PE.

Only the outer label is removed by PHP, not the inner VPN label.

Reference from Huawei HCIE-Datacom Documentation:

Huawei MPLS VPN Configuration Guide – Label Processing

HCIE-Datacom MPLS Traffic Engineering and PHP Mechanism

Huawei iMaster NCE-Campus MPLS VPN Implementation Guide

Dynamic VLAN Authorization in Huawei CloudCampus

Dynamic VLAN assignment allows users to be placed into specific VLANs based on authentication methods, ensuring security and network segmentation.

Correct Explanations:

✅ A. Wired users using 802.1X authentication receive VLAN assignments dynamically.

After authentication, the access control system (e.g., iMaster NCE-Campus) assigns VLANs dynamically.

✅ C. Wireless users using 802.1X authentication also receive VLAN assignments.

Similar to wired users, wireless 802.1X authentication allows dynamic VLAN assignment via the RADIUS server.

✅ D. Wired users using MAC authentication can receive VLAN assignments.

If a user does not support 802.1X, MAC authentication can still be used to assign VLANs dynamically.

Incorrect Statement Explanation:

❌ B. When wireless users pass Portal authentication, they join the authorization VLANs delivered to edge nodes.

Wrong! In Portal authentication, VLAN assignment is not dynamically delivered because Portal authentication typically applies access policies, not VLAN changes.

Dynamic VLAN assignment is mainly used with 802.1X or MAC authentication.

Reference from Huawei HCIE-Datacom Documentation:

Huawei CloudCampus Configuration Guide – Dynamic VLAN Assignment and Authentication

HCIE-Datacom Training Material – VLAN Authorization in Virtualized Campus Networks

Comprehensive and Detailed In-Depth Explanation:

In NETCONF (Network Configuration Protocol), the < config > operation can include operation attributes to specify how configuration data is handled:

merge (B): Merges the new configuration with the existing one.

replace: Replaces the existing configuration with the new one.

create (C): Creates a new configuration node, but will fail if the node already exists.

delete: Deletes an existing configuration node.

remove (A): Removes an existing node, but if the node does not exist, it will not generate an error.

The attribute " update " (D) is not a valid NETCONF operation attribute.

D is the correct answer as it does not exist within the NETCONF operation attribute set.

Comprehensive and Detailed In-Depth Explanation:

By default, OSPF does not automatically associate a domain ID with a process ID. The concept of " domain ID " is primarily used when redistributing routes between OSPF and BGP, particularly in MPLS VPN scenarios. The domain ID in OSPF helps maintain loop prevention and correct route advertisement between different OSPF domains. You can manually configure the domain ID using the domain-id command within the OSPF process view, but it is not inherently set to the process ID.

Comprehensive and Detailed In-Depth Explanation:

The statement A is incorrect because enabling DHCP snooping in the VLAN view only takes effect on interfaces within that specific VLAN that have DHCP snooping configured. It does not automatically apply to all interfaces of the device. Each interface within the VLAN must individually be configured or marked as trusted/untrusted.

B: Correct, as DHCP snooping, when enabled globally without any additional specifications, defaults to processing DHCPv4 messages.

C: Correct, as DHCP snooping can protect against DHCP spoofing attacks by marking interfaces as trusted or untrusted.

D: Correct, enabling DHCP snooping on an interface means it will monitor all DHCP messages on that specific interface.

There are three standard inter-AS MPLS VPN options, as per RFC 4364:

Option A (Back-to-Back VRF):

VRFs are directly connected between ASBRs using routing exchange (like static/BGP).

No label switching between ASs — no MPLS label needed between ASs.

Option B (EBGP Label Exchange):

ASBRs exchange labeled VPNv4 routes via EBGP.

One MPLS label is required — MPLS forwarding across AS boundary is used.

Option C (End-to-End LSP):

Full end-to-end LSP is created across ASs.

MPLS labels are definitely used end-to-end, even between ASs.

Option D (Commonly vendor-specific extensions based on Option B/C):

Similar to Option C — requires MPLS labels.

So:

B. Option B — needs MPLS label ✅

D. Option D — also needs MPLS label ✅

A. Option A — no MPLS label ❌

C. Option C — also uses MPLS label ✅, but not listed as an answer option in this question format (should have been).

Assuming valid options are A, B, D, the correct ones needing MPLS labels are:

Correct answers: B, D

Forwarding Equivalence Class (FEC) is a key concept in MPLS (Multiprotocol Label Switching), where packets with the same forwarding characteristics are grouped into an FEC and assigned a label.

Correct Answers (Cannot be Used for FEC Allocation):

A. Fragment Offset – Incorrect as an FEC allocation standard

Fragment offset is used for reassembling fragmented IP packets at the receiver side.

It is not relevant for MPLS label assignment.

B. Application Protocol – Incorrect as an FEC allocation standard

MPLS does not classify packets based on application-layer protocols (e.g., HTTP, FTP).

It works mainly at Layer 2 and Layer 3.

Incorrect Answers (Valid FEC Allocation Standards):

C. Destination Address – Valid FEC allocation criterion

One of the most common MPLS FEC classifications.

Packets with the same destination are grouped into the same FEC.

D. Class of Service (CoS) – Valid FEC allocation criterion

MPLS uses CoS-based traffic classification (e.g., Exp bits in MPLS headers).

Different CoS levels can be mapped to different labels.

Reference from Huawei HCIE-Datacom Documentation:

Huawei MPLS Technology Guide – FEC and Label Assignment

HCIE-Datacom MPLS VPN Configuration Guide