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

Understanding VXLAN and NVE Interfaces

VXLAN (Virtual Extensible LAN) allows for Layer 2 network extension over Layer 3 infrastructure.

???? Key VXLAN Components:

NVE (Network Virtualization Edge) Interface → VXLAN tunnels are created using one or more NVE interfaces.

BD (Bridge Domain) → Logical grouping of VXLAN traffic.

VNI (VXLAN Network Identifier) → 24-bit unique ID for traffic segmentation.

???? Analysis of Each Option:

✅ A. One NVE interface can be used for multiple VXLAN tunnels if ingress replication is used.

Correct: VXLAN tunnels can be dynamically learned using BGP EVPN, meaning multiple tunnels can use the same NVE interface.

✅ B. An NVE interface can be associated with multiple VNIs, allowing multiple BDs on one NVE.

Correct: Each NVE interface can carry multiple VNIs, reducing the need for separate interfaces.

❌ C. One NVE interface must be created per VXLAN tunnel.

Incorrect: Multiple VXLAN tunnels can share a single NVE interface.

❌ D. One NVE must be created for each BD.

Incorrect: One NVE can support multiple BDs.

???? Real-World Application:

Cloud Data Centers: VXLAN enables multi-tenant network segmentation.

Campus Networks: Simplifies Layer 2/Layer 3 connectivity across sites.

✅ Reference: Huawei HCIE-Datacom Guide – VXLAN and NVE Configuration

Comprehensive and Detailed Explanation:

VXLAN Symmetric IRB (Integrated Routing and Bridging) Forwarding is used for inter-subnet communication between different VXLAN networks.

✔ L3VNI is used for inter-subnet traffic → (A) Correct✔ Both ingress and egress VTEPs perform Layer 3 forwarding → (B) Correct

Why Are the Other Options Incorrect?

❌ C (Incorrect): The ingress VTEP uses both L2 and L3 forwarding (not just L2).❌ D (Incorrect): The egress VTEP also performs L3 forwarding before sending packets to the destination VTEP.

???? Reference: Huawei HCIE Datacom – VXLAN Symmetric IRB Forwarding

Understanding BGP Link State (BGP-LS)

???? What is BGP-LS?

BGP-LS (BGP Link-State) is an extension of BGP that allows routers to exchange network topology information via Link-State NLRI.

Helps SDN controllers and path computation elements (PCEs) make intelligent routing decisions.

???? What Does BGP-LS Advertise?✅ Node Information – Router IDs, Loopbacks✅ Link Information – Bandwidth, Delay, Cost✅ Prefix Information – Network Subnets✅ Topology Information – Full network graph

Why is the Answer TRUE?

✅ BGP-LS introduces a new NLRI format for advertising link-state information.✅ NLRI (Network Layer Reachability Information) is used to distribute topology data to SDN controllers.✅ It improves path optimization by enabling centralized traffic engineering decisions.

Real-World Application:

SDN-Based Traffic Engineering: Used in Segment Routing (SR) networks for centralized path selection.

MPLS TE (Traffic Engineering): Optimizes network paths dynamically based on real-time link-state data.

✅ Reference: Huawei HCIE-Datacom Guide – BGP Link-State (BGP-LS) Fundamentals

Authentication Header (AH) in IPsec

The Authentication Header (AH) protocol is part of IPsec and provides authentication, integrity, and replay protection but does NOT provide encryption.

✅ B. AH provides data origin authentication.

Ensures that packets come from a trusted source using cryptographic signatures.

✅ C. AH provides anti-replay protection.

Uses sequence numbers to prevent attackers from replaying old packets.

✅ D. AH provides data integrity authentication.

Ensures data integrity by verifying that packets have not been tampered with during transmission.

❌ A. AH provides packet encryption – Incorrect!

AH does not encrypt packet contents. It only authenticates headers.

ESP (Encapsulating Security Payload) is used for encryption in IPsec.

Reference from Huawei HCIE-Datacom Documentation:

Huawei IPsec Configuration Guide – AH vs. ESP

HCIE-Datacom Training Material – IPsec Security Mechanisms

Understanding Telemetry Encoding Formats

???? What is Telemetry?

Telemetry is a real-time network monitoring method that provides high-frequency data collection.

Used in AI-driven networks for predictive analytics and automation.

???? Common Telemetry Encoding Formats:

✅ GPB (Google Protocol Buffers)

Highly efficient binary format that reduces message size and CPU overhead.

Commonly used for high-speed, real-time analytics.

✅ JSON (JavaScript Object Notation)

Human-readable format, widely used in RESTful APIs.

Less efficient than GPB in high-speed telemetry but easier to debug.

???? Why is the Answer FALSE?❌ GPB is not mandatory; JSON can also be used in telemetry.✅ Huawei supports both GPB and JSON telemetry encoding formats.

Real-World Application:

Cloud Networking: Uses GPB for fast data collection and JSON for API-based telemetry visualization.

AI-Driven Networks: High-speed AI analytics leverage GPB encoding for efficiency.

✅ Reference: Huawei HCIE-Datacom Guide – Telemetry Encoding Formats and Data Collection

Comprehensive and Detailed Explanation:

✔ SR-MPLS Policy candidate paths are used for flexible path selection and load balancing in Segment Routing (SR-MPLS) networks.

✔ Correct Statements:✅ (A) Each candidate path can have multiple segment lists, each with its own weight for load balancing.✅ (B) Load balancing is supported both between candidate paths and within segment lists.✅ (C) An SR-MPLS Policy can contain multiple candidate paths, each with a preference value.✅ (D) The candidate path with the highest preference is selected as the primary path.

???? Reference: Huawei HCIE Datacom – SR-MPLS Policy Path Selection

Understanding SSH Authentication and Key Exchange

???? What Happens When an SSH Client Connects to a Server?1️⃣ Key Exchange Phase (KEX)

Even if only password authentication is used, SSH still performs key exchange.

The server and client negotiate encryption keys using algorithms like Diffie-Hellman (DH).

2️⃣ User Authentication Phase

After encryption keys are exchanged, the user authenticates using a username and password.

Why is the Answer FALSE?

❌ Even with password authentication, SSH still performs key exchange to establish an encrypted session.✅ The SSH session is always encrypted using cryptographic keys generated during KEX.

Real-World Application:

Secure Remote Access: Protects login credentials from MITM (Man-in-the-Middle) attacks.

Cloud & Datacenter Networks: Ensures secure SSH connections across remote infrastructure.

✅ Reference: Huawei HCIE-Datacom Guide – SSH Key Exchange and Authentication

Understanding Network Monitoring Data Categories

???? Network devices operate across three functional planes:

✅ A. Management Plane:

Handles device configuration, authentication, and monitoring.

Example: SNMP, SSH, NETCONF logs.

✅ B. Data Plane (Forwarding Plane):

Handles packet forwarding and switching.

Example: Interface statistics, traffic rates, dropped packets.

✅ C. Control Plane:

Handles routing, signaling, and protocol operations.

Example: BGP, OSPF, and MPLS signaling messages.

❌ D. Monitoring Plane (Incorrect Choice):

There is no "monitoring plane" in network architecture.

Monitoring tools collect data from management, control, and data planes, but do not form a separate plane.

Why is the Answer D (Monitoring-plane data)?

❌ Monitoring-plane does not exist as a separate category in network architecture.✅ O&M tools collect data from management, control, and data planes, but do not define a separate "monitoring plane".

Real-World Application:

Huawei iMaster NCE-Campus & iMaster NCE-WAN collect real-time network statistics and alarms.

Network Performance Monitoring (NPM) tools analyze control-plane events to detect failures.

✅ Reference: Huawei HCIE-Datacom Guide – Network Planes and Performance Monitoring

Understanding User Isolation in the Same VLAN

In a traditional VLAN, all devices within the same VLAN can communicate unless additional security policies are applied. To isolate users within the same VLAN, the following technologies can be used:

✅ B. Port Isolation (Private VLAN or Layer 2 Isolation)

Prevents communication between ports within the same VLAN.

Common in enterprise and campus networks to improve security.

Example: Isolating guest users from employees within the same VLAN.

✅ C. IPSG (IP Source Guard)

Blocks IP address spoofing within the same VLAN.

Uses DHCP snooping binding table to verify whether a device is using an authorized IP address.

✅ D. Ethernet Port Security

Limits the number of MAC addresses allowed per port.

Prevents unauthorized devices from communicating within the VLAN.

❌ A. Super VLAN (Incorrect Choice)

Super VLAN groups multiple VLANs under a single Layer 3 gateway, but it does not provide isolation within the same VLAN.

Real-World Application:

Public Wi-Fi Networks: Ensures that users within the same VLAN cannot communicate with each other.

Enterprise Security: Prevents unauthorized access or attacks within shared VLANs.

✅ Reference: Huawei HCIE-Datacom Guide – VLAN Security and User Isolation Technologies

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