Huawei H19-402_V1.0 HCSP-Presales – Data Center Network Planning and Design V1.0 Exam Practice Test

In Huawei CloudFabric VXLAN design, distributed gateway architecture is a key enhancement over traditional centralized gateway models, especially for large-scale data centers.

Option A is correct because distributed gateways (typically deployed on leaf nodes) only maintain local ARP/MAC entries for directly connected hosts. This significantly reduces ARP table pressure compared to centralized gateways, where a single device must learn all entries. This improves scalability and performance , which is critical in multi-tenant environments.

Option C is also correct as Huawei leaf switches can simultaneously act as Layer 2 VXLAN gateways (bridging) and Layer 3 VXLAN gateways (routing) . This enables distributed inter-subnet routing directly at the access layer, reducing latency and improving east-west traffic efficiency.

Option B is incorrect because it describes a limitation of centralized gateways , where traffic must traverse a central node, leading to suboptimal paths. Distributed gateways eliminate this issue.

Option D is also incorrect as it again describes centralized gateway constraints, not distributed ones.

Thus, distributed VXLAN gateways provide better scalability, optimal forwarding paths, and flexible deployment , making A and C correct .

In Huawei CloudFabric solutions integrated with OpenStack, Neutron is the key component responsible for network service management and integration with external network controllers such as iMaster NCE-Fabric .

Neutron provides APIs for creating and managing network resources such as:

Networks (VXLAN/BD)

Subnets

Ports

Routers

iMaster NCE-Fabric integrates with Neutron via northbound APIs , allowing it to automatically translate cloud network requests into underlay and overlay configurations (e.g., VXLAN, EVPN, routing policies) on physical network devices.

Other components:

Nova (A) manages compute resources (VM lifecycle)

Keystone (B) handles authentication and identity services

Cinder (C) provides block storage services

These components do not directly interact with network controllers for fabric provisioning.

Huawei emphasizes tight integration between Neutron and iMaster NCE-Fabric to enable automated, policy-driven network deployment , which is essential for cloud data center operations.

Therefore, the correct answer is D (Neutron) .

In Huawei CloudFabric’s cloud-network integration scenario , the SDN controller iMaster NCE-Fabric must interconnect with multiple key components to enable end-to-end automation and orchestration .

Cloud platform (A): Platforms such as OpenStack or ManageOne integrate with iMaster NCE-Fabric via northbound APIs. This allows automatic network provisioning when tenants create networks, VMs, or services.

VMM (C - Virtual Machine Manager): Integration with virtualization platforms (e.g., VMware vCenter, FusionSphere) enables dynamic VM-aware networking, including automatic port and policy configuration.

Physical switch (D): These are the core devices controlled by iMaster NCE-Fabric. The controller pushes configurations (VXLAN, EVPN, routing) to build the underlay and overlay fabric.

Firewall (B) is typically integrated as a service device (VAS) but is not directly required to interconnect with the controller in all scenarios. It is usually inserted via service chaining rather than direct control-plane integration.

Huawei emphasizes controller-based automation , where iMaster NCE-Fabric coordinates between cloud platforms, virtualization systems, and physical network devices.

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

In OpenStack Neutron, the core network abstraction models are Network, Subnet, and Port , which align with Huawei CloudFabric’s logical network design principles. A Network represents a Layer 2 broadcast domain, similar to a VXLAN segment (VNI) in Huawei data center fabrics. It provides tenant-level isolation and forms the foundation for overlay networking.

A Subnet defines the Layer 3 IP addressing scheme within a network, including CIDR blocks, gateway addresses, and DHCP configurations. This aligns with Huawei’s underlay/overlay separation, where IP addressing is critical for both service reachability and automation.

A Port is the connection point between a virtual machine (VM) and the virtual network, equivalent to a virtual NIC. It carries MAC/IP bindings and security policies, similar to endpoint definitions in EVPN-based fabrics.

The option vRouter is incorrect because Neutron uses the concept of a Router , not “vRouter,” and it is considered a higher-layer service component rather than a fundamental network model. Huawei documentation consistently emphasizes these three as the foundational constructs for virtualized network design.

In Huawei CloudFabric and VXLAN-based overlay networking, the overlay provides abstraction, flexibility, and scalability by decoupling logical services from the physical infrastructure. NVEs (Network Virtualization Edge nodes) can indeed be deployed on physical switches (such as leaf switches), which is a fundamental capability of hardware-based VXLAN fabrics. Additionally, overlay networks are designed to meet the needs of private cloud environments, offering high performance, simplified O & M, and enhanced security through network segmentation (e.g., VXLAN VNIs).

Overlay networks also support access for both virtual machines and physical servers, ensuring consistent connectivity regardless of workload type.

However, statement D is incorrect. In Huawei’s architecture, especially with BGP EVPN-based VXLAN, the control plane is distributed rather than relying on a controller to synchronously deliver flow tables. Devices dynamically learn and exchange forwarding information using EVPN. Even in SDN-based scenarios with iMaster NCE-Fabric, policy delivery is not strictly synchronous flow table pushing in the traditional sense (like OpenFlow).

Therefore, “controller delivers flow tables synchronously” is not a standard capability of Huawei overlay networks, making option D incorrect.

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 .

RDMA (Remote Direct Memory Access) is a key technology in Huawei’s Intelligent Lossless Data Center Network , widely used in high-performance scenarios such as AI training, distributed storage, and HPC.

The statement is correct because RDMA enables direct memory-to-memory data transfer between servers without involving the CPU or operating system in the data path. This bypass mechanism significantly reduces overhead and enables:

Ultra-low latency (microsecond-level communication)

High throughput (efficient use of bandwidth)

Low CPU utilization , freeing compute resources for applications

Although RDMA was originally developed for InfiniBand networks , it is now widely used over Ethernet through technologies like RoCE (RDMA over Converged Ethernet) in Huawei CloudFabric solutions.

To support RDMA effectively, Huawei implements lossless Ethernet mechanisms such as PFC, ECN, and congestion control algorithms to ensure reliable packet delivery.

Therefore, the statement accurately describes RDMA characteristics and is TRUE .

The key difference between M-LAG and stacking in Huawei data center design lies in their control plane architecture and fault domains .

Option A is false because M-LAG does NOT have a centralized control plane . Instead, each device in an M-LAG pair maintains its own independent control plane , while synchronizing state information (such as MAC and ARP tables) over the peer-link. This distributed control design improves reliability and avoids a single point of failure.

Option B is correct : M-LAG involves two independent switches , both of which must be managed (though automation tools like iMaster NCE-Fabric simplify this).

Option C is correct : M-LAG provides fault domain isolation . A failure on one device does not impact the control plane of the other, enhancing network resilience.

Option D is correct : In contrast, stacking uses a single control plane , so upgrades can be more complex and potentially disruptive, affecting the entire stack.

Huawei best practices favor M-LAG over stacking in modern data centers due to its distributed control, higher reliability, and better fault isolation .

Therefore, the correct answer is A .

According to Huawei’s CloudFabric intelligent O & M description, the health model is built as a multi-dimensional evaluation system that assesses the network from five dimensions: device, network, protocol, overlay, and service . This means every option listed in the question is part of the CloudFabric health model. Huawei explains that this model integrates telemetry-assisted data such as configuration data, forwarding entry data, logs, and KPI performance information, allowing the platform to detect faults and risks in real time across these five layers.

In practical Huawei CloudFabric operations, the device layer focuses on node health, hardware state, and resource status; the network layer checks connectivity and path quality; the protocol layer verifies control-plane protocols and convergence behavior; the overlay layer evaluates virtualized forwarding networks such as VXLAN fabrics; and the service layer measures the actual service experience and traffic exchange status. Huawei explicitly presents these five as the full health-evaluation scope of CloudFabric intelligent O & M, so the correct response is all five options

In Huawei CloudFabric and modern data center architectures, the underlay and overlay networks are designed as independent layers with clear separation of responsibilities. The underlay network provides basic IP connectivity using standard Layer 3 routing (commonly using protocols such as OSPF, IS-IS, or even static routing), ensuring reliable transport between network devices.

The overlay network, typically implemented using VXLAN with BGP EVPN as the control plane, builds logical Layer 2/Layer 3 services on top of the underlay. Importantly, the overlay does not require the same routing protocol as the underlay. This independence allows flexible design, scalability, and easier evolution of services without modifying the physical infrastructure.

Option A is correct because endpoints (servers, VAS devices) are unaware of the underlay—they only interact with the overlay. Option C is correct as VXLAN is the mainstream overlay encapsulation technology. Option D correctly defines the overlay as a logical abstraction over the physical network.

Thus, statement B is false because Huawei explicitly supports different protocols between underlay and overlay layers.

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

Huawei data center materials describe a high-performance network using core technical indicators such as high throughput, low latency, and zero packet loss . These are the actual network characteristics used to evaluate whether a data center fabric can efficiently support AI computing, storage traffic, and east-west service communication. In Huawei’s intelligent lossless network design, the purpose is to build a fabric that forwards traffic at high speed, minimizes delay, and prevents packet loss under heavy load.

By contrast, Higher GPU computing power is not a direct network characteristic. It is an effect or business benefit that can result when the network performs well. Huawei explains that intelligent lossless networking improves AI cluster efficiency and helps computing resources operate more effectively, but GPU power itself belongs to the computing layer, not the network feature set. The network supports better GPU utilization; it does not define GPU computing power as one of its own characteristics.

Therefore, the correct answer is B .

In Huawei CloudFabric Solution, health check and intelligent O & M are performed across multiple key dimensions to ensure stable, secure, and efficient network operations. These dimensions provide a comprehensive view of the data center network’s health.

Capacity (A): Evaluates resource utilization such as bandwidth, device capacity, and scalability limits to prevent bottlenecks.

Status (B): Monitors the operational state of devices, links, and services (up/down, faults, alarms).

Connectivity (D): Verifies end-to-end network reachability, ensuring that services and tenants can communicate properly across the fabric.

Security policy (E): Checks correctness and consistency of policies such as ACLs, segmentation, and service chaining rules.

Performance (F): Measures latency, packet loss, throughput, and congestion, which are critical in modern workloads like AI and storage.

VM (C) is not considered a core health check dimension at the network level. It belongs more to the compute/virtualization domain rather than network O & M.

Huawei iMaster NCE-FabricInsight uses these dimensions to provide proactive fault detection, root cause analysis, and optimization recommendations , ensuring intelligent lifecycle management of the data center network.

In Huawei data center network design, particularly in large-scale CloudFabric architectures, Points of Delivery (PoDs) are a fundamental concept used to enable modular scalability, simplified management, and efficient resource pooling. A PoD typically consists of a group of servers, access switches (Leaf), and sometimes aggregation resources that function as a repeatable building block within the data center.

By dividing a data center into multiple PoDs, operators can achieve horizontal scalability , where additional capacity is added by deploying new PoDs without impacting existing services. This aligns with Huawei’s spine-leaf architecture, where each PoD connects to a common spine layer, ensuring consistent performance and low latency.

PoDs also improve fault isolation and operational efficiency , as issues can be contained within a specific module. From a management perspective, this structure simplifies provisioning, monitoring, and automation through platforms like iMaster NCE-Fabric.

Therefore, the statement is TRUE , as PoD-based design is a widely adopted best practice in Huawei data center planning and modern cloud infrastructures.

In Huawei CloudFabric design, M-LAG (Multi-Chassis Link Aggregation) is widely used to provide active-active forwarding and high availability at the access and border layers. When border leaf nodes are deployed in an M-LAG pair, they typically connect to upstream PE (Provider Edge) devices in a dual-homing (square topology) manner, ensuring both link-level and device-level redundancy.

However, Huawei design guidelines clearly state that an interconnection link (commonly called a peer-link or bypass link) between M-LAG devices is mandatory. This link is essential for synchronization of forwarding states, MAC address tables, ARP/ND entries, and control plane information between the two devices. It also ensures proper traffic forwarding in failure scenarios, such as when one device loses its uplinks but remains operational.

Without this peer-link, traffic consistency and loop prevention mechanisms cannot function correctly, leading to potential traffic loss or loops. Therefore, even in dual-egress scenarios with PE devices, the bypass/peer link is still required.

Hence, the statement is FALSE.

In Huawei routing principles, route selection follows a strict hierarchy. When multiple routing protocols advertise routes to the same destination, the system first compares the route preference (priority) , not the cost. The route with the lowest preference value (highest priority) is selected. Only within the same routing protocol are cost/metric values compared to determine the best route.

Option A is correct because only one optimal route is installed in the routing table at a time, based on protocol preference. Option B is also correct: direct routes are automatically generated for networks connected to local interfaces. Option C is valid as Huawei devices support route import (redistribution) between routing protocols, enabling flexible network design.

Option D is incorrect because it reverses the decision logic. It incorrectly states that cost is compared before priority, which contradicts Huawei’s routing selection process.

Therefore, the false statement is D .

In Huawei VXLAN architecture, all listed statements accurately reflect core design concepts used in CloudFabric deployments.

A is correct: a Virtual Interface (VBDIF/VirtualIF) is a Layer 3 interface associated with a Bridge Domain (BD) , enabling inter-subnet routing (distributed gateway function).

B is correct: Huawei VXLAN commonly uses a 1:1 mapping between VNI and BD , where the BD acts as the Layer 2 forwarding domain. This mapping ensures clear separation of tenant networks and simplifies forwarding logic.

C is correct: VXLAN encapsulation uses VTEP (VXLAN Tunnel Endpoint) IP addresses . The source IP is the local VTEP, and the destination IP is the remote VTEP. Together, they logically represent the VXLAN tunnel used for transporting overlay traffic across the IP underlay.

D is also correct: a VAP (Virtual Access Point) represents the service access interface. On Huawei CE switches, VAPs are typically implemented using VLAN-based access , meaning VLANs act as the entry point for VXLAN services.

These concepts are fundamental in Huawei EVPN-VXLAN fabrics, enabling scalable, multi-tenant, and automated data center networking.

Huawei’s AI Fabric solution is designed to build a unified, intelligent lossless data center network by integrating traditionally separate network infrastructures into a single converged Ethernet-based fabric.

The three integrated networks are:

Computing network (C): Handles east-west traffic between compute nodes (e.g., AI training clusters, GPU servers).

Storage network (B): Supports high-throughput, low-latency storage access (e.g., distributed storage systems like HDFS or Ceph).

Ethernet network (D): Provides the underlying IP-based transport, enabling unified connectivity and scalability.

Traditionally, InfiniBand (IB) networks were used for high-performance computing due to their low latency and RDMA capabilities. However, Huawei AI Fabric replaces IB with lossless Ethernet (RoCE-based) solutions, allowing all services (compute + storage + management) to run over a single Ethernet fabric .

This convergence reduces:

Network complexity

Capital and operational costs

Management overhead

While improving:

Resource utilization

Scalability

Automation

Therefore, the correct three networks are Storage, Computing, and Ethernet , making B, C, and D correct .

In Huawei CloudFabric architecture, server leaf nodes and service leaf nodes have distinct roles, even though both can function as NVEs (Network Virtualization Edge devices) in a VXLAN network.

A server leaf node primarily provides access for compute resources , such as physical servers and virtual machines. It acts as a common NVE, handling VXLAN encapsulation/decapsulation for tenant traffic and enabling communication within the overlay network.

However, firewalls and load balancers (LBs) are classified as value-added service (VAS) devices and are typically connected to service leaf nodes , not standard server leaf nodes. Service leaf nodes are specifically designed to handle service insertion, traffic steering, and policy-based forwarding required for these devices.

Although in some simplified deployments roles may be combined, Huawei standard design clearly separates:

Server leaf → compute access

Service leaf → VAS device access (FW, LB, etc.)

Therefore, the statement is FALSE , as server leaf nodes do not typically provide access for firewalls and load balancers in standard CloudFabric architecture.