H12-921-V1-0 Sample Questions & Answers

This is true. The microsegmentation model in solutions like Huawei CloudFabric (similar to Cisco ACI) operates on a zero-trust, whitelist principle. By default, all traffic between different EPGs is denied, even if they belong to the same VRF or subnet. A contract, which defines the allowed protocols and ports, must be explicitly configured and applied between the source and destination EPGs to permit communication.

In a tightly integrated environment, when a developer creates a LoadBalancer service in Kubernetes, the API request is intercepted. The Huawei CNI plugin communicates this request to the iMaster NCE-Fabric controller. NCE-Fabric then orchestrates the allocation of an external IP address (from a predefined pool) and programs the border leaf switches with the necessary NAT and load balancing rules to direct external traffic to the correct service pods.

This design is the optimal solution. Deploying distributed anycast gateways on all VTEPs (leaf switches) in both data centers allows VMs to use a consistent gateway IP regardless of their location. Extending the EVPN control plane between the DCs allows for the exchange of L2 (MAC/IP) and L3 (IP Prefix) reachability information. This enables seamless L2 extension for VM mobility and ensures that inter-DC traffic is routed optimally without trombone effects. EVPN multihoming on the DCI links provides redundancy and load balancing.

The oversubscription ratio is calculated by dividing the total bandwidth of the server-facing ports (downlinks) by the total bandwidth of the uplink ports.
Total Downlink Bandwidth = 48 ports * 25 Gbps = 1200 Gbps.
Total Uplink Bandwidth = 8 ports * 100 Gbps = 800 Gbps.
Ratio = Downlink / Uplink = 1200 / 800 = 1.5.
Therefore, the oversubscription ratio is 1.5:1.

The HTTP status code 401 Unauthorized specifically indicates that the request lacks valid authentication credentials. Before making functional API calls to iMaster NCE-Fabric, a client must first authenticate (typically with a username/password) to a login endpoint to obtain a temporary access token. This token must then be included in the header (e.g., X-Auth-Token) of all subsequent requests. A missing or expired token will result in a 401 error.

While high bandwidth is important, distributed storage systems like FusionStorage are extremely sensitive to latency. Data is often replicated across multiple nodes for redundancy, and I/O operations require coordination and acknowledgments between these nodes. High or unpredictable latency (jitter) can severely delay these operations, leading to poor application performance. Therefore, designing a network with low, consistent latency is the most critical factor.

The EVPN Type-3 route is used to automate the discovery of VTEPs participating in a specific VNI and to establish tunnels for forwarding BUM traffic. When a VTEP learns of a new VNI, it advertises a Type-3 route. Other VTEPs receive this route and add the originating VTEP to a flood list for that VNI. This allows for the creation of an ingress replication tree to handle BUM traffic without manual configuration.

This is the ideal solution. The application servers and database servers would be placed into separate Endpoint Groups (EPGs). This provides the initial isolation (microsegmentation). Then, a Service Function Chain (SFC) would be created that defines the virtual firewall as a service function. A contract linking the two EPGs would be configured to use this SFC, forcing all communication between them to be inspected by the firewall, thus meeting the compliance requirements in an automated, policy-driven manner.

The standard and most scalable design for interconnecting multiple spine-leaf PoDs is to introduce a third tier, known as the 'Super Spine' or 'Core' layer. The spine switches from each PoD connect to all super spine switches. This creates a three-stage Clos network that maintains predictable latency and allows for seamless inter-PoD communication and horizontal scaling of the data center.

This is true. A key principle of SDN controllers like iMaster NCE-Fabric is to act as the single source of truth for the network configuration. The controller maintains the desired state and continuously ensures the network devices conform to it. Manual changes made via CLI are considered 'out-of-band' and will be detected during synchronization. NCE-Fabric will then overwrite these manual changes to restore the centrally defined configuration, ensuring consistency and preventing configuration drift.