Free Huawei H19-402_V1.0 Practice Exam with Questions & Answers

In Huawei data center network design, M-LAG (Multi-Chassis Link Aggregation) is widely used to build loop-free Layer 2 topologies without relying on Spanning Tree Protocol (STP) . This is a key advantage in modern CloudFabric architectures.

Traditional Layer 2 networks depend on STP to prevent loops, but STP introduces drawbacks such as blocked links, slow convergence, and inefficient bandwidth utilization . M-LAG eliminates these issues by allowing two physical switches to operate as a single logical device from the perspective of downstream nodes.

With M-LAG:

All links are active-active , maximizing bandwidth usage

Loop prevention is achieved through protocol mechanisms and peer-link synchronization , not STP

Convergence is much faster compared to STP-based designs

Network design becomes simpler and more predictable

Huawei best practices strongly recommend disabling STP in M-LAG-based data center fabrics , especially when combined with VXLAN EVPN, to achieve high performance, fast convergence, and simplified operations .

Therefore, the statement is TRUE .

Comprehensive and Detailed 150 to 200 words of Explanation From Huawei data center:

After rechecking against Huawei’s own materials, the verified multi-select answer is B and D . Huawei documentation for Elastic Load Balance, which is the load-balancing architecture referenced in Huawei cloud/data center designs, states that for Layer 4 traffic using TCP/UDP , incoming traffic is routed only through the LVS cluster . For Layer 7 traffic using HTTP/HTTPS , incoming traffic is routed first to the LVS cluster and then to the Nginx cluster before reaching backend servers. That means Huawei explicitly uses LVS for L4 load balancing and Nginx together with LVS for L7 load balancing.

By contrast, IP ECMP is a Layer 3 equal-cost forwarding/load-sharing mechanism, not an L4-L7 service load balancer in Huawei’s CloudFabric context. Huawei’s ECMP documentation discusses route-based traffic distribution in the IP layer, which is fundamentally different from application/service load balancing.

In Huawei CloudFabric architecture, the underlay network is the physical IP fabric, while the overlay network is a logical network built on top of it using technologies like VXLAN and BGP EVPN .

Option A is false because the overlay network does not require bare optical fibers . It operates independently of the physical medium and can run over any IP-based underlay (Ethernet, optical, etc.). The overlay abstracts the physical infrastructure.

Option B is correct : the underlay network is transparent to endpoints (servers, firewalls, routers). These devices only interact with the overlay and are unaware of the underlying transport.

Option C is correct : the overlay has its own forwarding plane (VXLAN encapsulation) and control plane (BGP EVPN) , enabling scalable and automated network virtualization.

Option D is correct : the overlay is a logical network built over the underlay , providing tenant isolation and flexible service deployment.

Huawei best practices emphasize decoupling overlay from underlay , ensuring flexibility, scalability, and simplified operations.

Therefore, the correct answer is A .

In Huawei CloudFabric and VXLAN-based data center designs, it is a best practice to use the IP address of a loopback interface as the VTEP (VXLAN Tunnel End Point) source address instead of a physical interface IP. This recommendation is based on reliability, stability, and operational flexibility.

A loopback interface is always in the UP state as long as the device is operational, whereas physical interfaces may go down due to link failures. If a physical interface IP is used as the VTEP source, any link failure would cause VXLAN tunnels to flap, impacting service continuity. In contrast, loopback interfaces remain reachable through the underlay network via dynamic routing protocols such as OSPF, IS-IS, or BGP, ensuring consistent tunnel endpoints.

Additionally, using loopback addresses supports ECMP (Equal-Cost Multi-Path) forwarding in the underlay, improving load balancing and network utilization. Huawei documentation strongly emphasizes this design principle to enhance VXLAN tunnel resilience and simplify network operations. Therefore, the statement is TRUE.

In Huawei data center networking, M-LAG (Multi-Chassis Link Aggregation Group) is a critical technology used to provide active-active access, high availability, and link redundancy . It allows a downstream device (such as a server) to establish a single logical Eth-Trunk across two separate physical switches (DeviceA and DeviceB).

From the server’s perspective, both upstream switches appear as one logical device , which eliminates the need for protocols like STP and enables simultaneous forwarding on all active links . This significantly improves bandwidth utilization and avoids blocked links.

The key advantage highlighted in the statement is the improvement of reliability from card-level to device-level . In traditional single-device link aggregation, failures are limited to interface cards. However, with M-LAG, even if an entire switch (device-level failure) goes down, traffic continues to flow through the other active switch without interruption.

Huawei CloudFabric widely adopts M-LAG + VXLAN EVPN to ensure high reliability, fast convergence, and continuous service availability .

Therefore, the statement is TRUE .

Huawei defines VXLAN (Virtual Extensible LAN) as an overlay virtualization technology that functions similarly to a Layer 2 VPN , enabling the extension of Layer 2 networks across Layer 3 infrastructures. VXLAN encapsulates Ethernet frames within UDP packets, allowing tenants to build isolated virtual networks over any IP underlay with reachable routing.

The statement is correct because VXLAN enables Layer 2 adjacency across geographically distributed data centers , which is a key requirement in cloud and virtualization environments. It supports large-scale multi-tenant isolation using VNIs (VXLAN Network Identifiers) , significantly exceeding VLAN limitations.

Additionally, VXLAN gateways (either centralized or distributed) play a crucial role. They provide communication:

Within VXLAN networks (intra-subnet and inter-subnet via distributed gateways)

Between VXLAN and traditional networks (e.g., bare-metal servers or legacy VLAN-based systems)

Huawei CloudFabric solutions heavily rely on VXLAN with BGP EVPN control plane to achieve scalable, automated, and efficient data center networking.

Therefore, the statement is TRUE .

In Huawei CloudFabric architecture, service integration and flexible deployment of security devices such as firewalls are key design principles. Firewalls can be deployed in multiple ways depending on service requirements, traffic patterns, and scalability considerations.

Firewalls can be connected to:

Service leaf nodes : These are dedicated nodes used for service insertion (e.g., firewall, load balancer). Traffic can be steered through these nodes using policy-based routing or service chaining.

Border leaf nodes (combined with service leaf role) : In some designs, border leaf nodes (which connect to external networks such as WAN or Internet) can also integrate service functions, including firewall connectivity. This reduces hardware requirements and simplifies deployment.

Huawei supports both centralized and distributed service deployment models , allowing firewalls to be flexibly inserted into the network fabric. Integration is typically achieved using VXLAN, EVPN, and service chaining technologies , ensuring seamless traffic steering and policy enforcement.

This flexibility enhances:

Network scalability

Security enforcement

Operational simplicity

Therefore, the statement is TRUE .

Huawei iMaster NCE-Fabric ZTP (Zero Touch Provisioning) is designed to enable automated, fast, and error-free deployment of data center network devices, significantly reducing manual configuration efforts.

All listed options are valid characteristics:

Plug-and-play (A): Devices can automatically obtain configurations once powered on and connected to the network, requiring minimal manual intervention.

Visualized device onboarding (B): The controller provides a graphical interface to monitor onboarding progress, topology, and device status, improving deployment visibility.

Link verification (C): ZTP includes automatic cabling and link detection/verification , ensuring correct physical connections before service provisioning.

Batch device onboarding (D): Multiple devices can be onboarded simultaneously, enabling large-scale data center deployment with high efficiency.

Huawei emphasizes ZTP as a key capability in CloudFabric for:

Rapid service rollout

Reduced human error

Standardized deployment

Simplified O & M

This aligns with Huawei’s goal of achieving fully automated and intelligent data center network provisioning .

Therefore, the correct answers are A, B, C, and D .

In Huawei M-LAG design, the peer-link is a critical connection between two M-LAG member devices used for synchronization of control information (such as MAC address tables, ARP entries, and state information) and for forwarding certain types of traffic like broadcast, multicast, and unknown unicast (BUM) traffic when necessary.

However, to prevent traffic loops and duplication , Huawei enforces strict isolation between peer-link interfaces and dual-homed M-LAG member interfaces . Specifically, this relationship is bidirectionally isolated , meaning traffic received from a dual-homed interface is not forwarded to the peer-link and then back to another dual-homed interface, and vice versa.

This bidirectional isolation ensures:

Loop prevention without relying on STP

Avoidance of duplicate packet forwarding

Efficient traffic handling in active-active scenarios

BUM traffic is only forwarded over the peer-link under controlled conditions, not blindly between all interfaces. Huawei CloudFabric best practices emphasize this isolation to maintain stable and predictable forwarding behavior in M-LAG deployments.

Therefore, the correct answer is C (Bidirectionally isolated) .

In IPv6, the concept of broadcast addresses does not exist , which is a fundamental difference from IPv4. Instead of broadcast, IPv6 uses multicast and anycast to achieve similar communication functions more efficiently. Therefore, statement B is false , as there is no such thing as an IPv6 broadcast address with all bits set to 1.

Statement A is correct: Unique Local Addresses (ULA) are intended for internal communication within a site or organization and are not routable on the public Internet, similar to IPv4 private addresses.

Statement C is also correct: Global Unicast Addresses in IPv6 are globally routable and function similarly to public IPv4 addresses, enabling end-to-end communication across networks.

Statement D is correct as well: Link-local addresses (FE80::/10) are automatically configured and used only for communication within the same local link (e.g., for neighbor discovery and routing protocols).

Huawei data center designs emphasize IPv6’s efficiency and scalability, particularly its elimination of broadcast traffic, which improves network performance and reduces unnecessary load.