H19-402_V1.0 HCSP-Presales – Data Center Network Planning and Design V1.0 Questions and Answers

Huawei data center solutions emphasize the transition toward all-flash data centers as a key enabler of enterprise digital transformation. Traditional HDD-based storage systems cannot meet the performance requirements of modern applications such as AI, big data analytics, cloud computing, and real-time services .

SSD (Solid-State Drive) technology provides significant advantages over HDDs, including:

Ultra-low latency (microseconds vs milliseconds)

High IOPS (Input/Output Operations Per Second)

Better reliability and durability (no mechanical parts)

Lower power consumption and higher density

As a result, SSDs have become the mainstream storage medium in modern data centers, especially in Huawei’s all-flash storage solutions (e.g., OceanStor Dorado) .

All-flash data centers enable:

Faster application response times

Improved user experience

Efficient support for AI and distributed workloads

Simplified storage architecture

Huawei promotes integrating all-flash storage with intelligent lossless networks (RoCE-based) to achieve end-to-end high-performance infrastructure.

Therefore, the statement is TRUE .

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 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 .

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) .

The statement is false due to an incorrect description of in-band management communication .

Huawei iMaster NCE-Fabric indeed supports both in-band and out-of-band deployment modes , but the interfaces used are misrepresented:

In in-band mode , iMaster NCE-Fabric uses southbound interfaces (not northbound) to communicate with switches over the service network . These southbound interfaces are responsible for delivering configurations and collecting device information.

In out-of-band mode , the description is correct: the controller connects to device management interfaces via a dedicated management network , ensuring separation from service traffic.

The confusion arises because:

Northbound interfaces are used for communication between the controller and upper-layer systems (e.g., cloud platforms like OpenStack or ManageOne).

Southbound interfaces are used for communication between the controller and network devices .

Huawei architecture strictly separates these roles to enable clear control-plane layering and automation .

Therefore, because the statement incorrectly mentions northbound interfaces in in-band mode , the correct answer is FALSE .

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 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.

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 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 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 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 CloudFabric and cloud networking models (aligned with OpenStack and SDN-based architectures), a VPC (Virtual Private Cloud) represents an isolated tenant network environment that contains multiple logical networking components.

Within a VPC:

A logical router provides Layer 3 routing and interconnection between subnets . Typically, one logical router is associated with a VPC to manage north-south and east-west routing.

Multiple logical switches (VXLAN networks or BDs) can be created to represent different Layer 2 segments within the same tenant environment.

Each logical switch can have multiple logical ports , which represent VM interfaces, containers, or service endpoints connected to the network.

This hierarchical design allows:

Flexible network segmentation

Multi-tier application deployment (web/app/db tiers)

Scalable tenant isolation

Huawei CloudFabric, integrated with platforms like iMaster NCE-Fabric and ManageOne , automates the creation and orchestration of these components.

Therefore, the statement is TRUE , as it accurately reflects the standard VPC network model.

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 architecture, logical switches are a key abstraction used to simplify network service deployment and management. These logical switches are built on top of VXLAN Layer 2 networks and represent virtualized broadcast domains (similar to VLANs, but more scalable).

Huawei extends the function of these logical switches by integrating distributed Layer 3 gateway capabilities directly into them. This means that each logical switch can provide both Layer 2 connectivity and Layer 3 routing services (commonly referred to as distributed gateways). These gateways are typically implemented on leaf nodes using VXLAN with BGP EVPN as the control plane.

As a result, traffic between subnets can be routed locally at the ingress leaf switch without needing to traverse to a centralized gateway, significantly improving efficiency and reducing latency. Logical ports connected to these logical switches automatically receive gateway services, enabling seamless inter-subnet communication.

This design aligns with Huawei’s intent of decoupling physical and logical networks while providing scalable, agile, and highly efficient data center networking. Therefore, the statement is TRUE.

In Huawei’s intelligent O & M architecture, NETCONF is a modern network management protocol designed for transactional, reliable, and concurrent-safe configuration management . One of its key features is the lock mechanism , which allows a user or system to lock a configuration datastore (such as candidate or running configuration) to prevent other users or processes from making conflicting changes simultaneously. This ensures consistency, atomic operations, and rollback capability , which are critical in automated data center environments like CloudFabric.

On the other hand, SNMP (Simple Network Management Protocol) is primarily designed for monitoring and basic configuration , but it lacks advanced transaction control features. SNMP does not support configuration locking or transactional commits, meaning multiple users can overwrite each other’s changes, potentially leading to configuration inconsistencies.

Huawei strongly recommends using NETCONF/YANG-based automation (e.g., via iMaster NCE-Fabric) for modern data center operations because it provides structured data modeling, conflict prevention, and programmability , which SNMP cannot offer.

Therefore, the statement is TRUE .