H12-893_V1.0 Questions and Answers

iMaster NCE-Fabric automates network configuration delivery in Huawei’s CloudFabric. Let’s evaluate each statement:

A. Logical switches are mainly used for Layer 3 communication between hosts on a VXLAN network. These switches correspond to Layer 3 gateway configurations such as VBDIF interface and VPN instance configurations on physical devices:This is false. Logical switches in iMaster NCE-Fabric primarily handle Layer 2 communication (e.g., bridging within a VNI), corresponding to Bridge Domains (BDs) and Layer 2 VNIs. Layer 3communication is managed by gateways, not logical switches.FALSE.

B. An end port represents an online host. It corresponds to the traffic encapsulation type (whether a VLAN tag is carried) configured on a Layer 2 sub-interface of a physical device:This is true. End ports map to host connections, with encapsulation (VLAN-tagged or untagged) configured on sub-interfaces.TRUE.

C. A logical port is equivalent to an independent physical port that is used by a host to connect to a VXLAN network. It corresponds to the Layer 2 sub-interface configuration on a physical device:This is true. Logical ports represent host connections, mapped to Layer 2 sub-interfaces for VXLAN access.TRUE.

D. Logical switches are mainly used for Layer 2 communication between hosts on a VXLAN network. These switches correspond to BD and Layer 2 VNI configurations on physical devices:This is true. Logical switches facilitate Layer 2 connectivity, aligning with BD and VNI settings.TRUE.

Thus,Ais the false statement because logical switches are for Layer 2, not Layer 3, communication.References:Huawei CloudFabric Data Center Network Solution – iMaster NCE-Fabric Configuration; HCIP-Data Center Network Training – Logical Network Mapping.

In Huawei’s CloudFabric Solution, iMaster NCE-Fabric automates overlay network (e.g., VXLAN) configuration, while the underlay network is manually deployed. Tenant hosts failing to access external networks indicate a connectivity issue, likely at the overlay-underlay boundary or security layer. Let’s evaluate each option as a possible cause:

A. No return route is configured on the PE:This is a possible cause. The Provider Edge (PE) device (e.g., border leaf or router) must have a return route to the tenant’s VXLAN network for external access. Without it, traffic from external networks cannot reach the DC.POSSIBLE CAUSE.

B. The engineer did not check whether the service loopback interface needs to be configured on the VXLAN network based on the switch model:This is a possible cause. Some Huawei switch models (e.g., CE series) require a service loopback interface as the VTEP source IP. If omitted or misconfigured based on the model, external connectivity fails.POSSIBLE CAUSE.

C. No firewall security policy is configured when host traffic passes through the firewall:This is a possible cause. If a firewall is in the path (e.g., between tenant VPC and external network), a missing security policy (e.g., allowing outbound traffic) blocks access.POSSIBLE CAUSE.

D. The MAC address of the NVE interface on the VXLAN network is not manually specified:This is not a possible cause. The Network Virtualization Edge (NVE) interface in VXLAN does not require a manually specified MAC address; it uses the switch’s system MAC or auto-generates one. iMaster NCE-Fabric typically handles this automatically, and manual specification is neither required nor a common fault point for external access issues.NOT A POSSIBLE CAUSE.

Thus,Dis not a possible cause of the fault.References:Huawei CloudFabric Data Center Network Solution – Troubleshooting Guide; HCIP-Data Center Network Training – VXLAN Connectivity.

Centralized gateway deployment using BGP EVPN in Huawei’s data center networks (e.g., CloudFabric) involves a gateway handling Layer 3 routing for VXLAN overlays. Let’s evaluate each statement:

A. When configuring a VTEP, you need to create a Layer 2 BD and bind a VNI to the Layer 2 BD:A Bridge Domain (BD) is a Layer 2 broadcast domain in VXLAN, and a Virtual Network Identifier (VNI) is bound to it to segment traffic. This is a standard step when configuring a VXLAN Tunnel Endpoint (VTEP) to map the overlay network.TRUE.

B. A VXLAN tunnel is identified by a pair of VTEP IP addresses and can be established if the local and remote VTEP IP addresses are reachable to each other at Layer 3:VXLAN tunnels are established between VTEPs using their IP addresses as endpoints. Layer 3 reachability (e.g., via underlay routing) is required for tunnel establishment.TRUE.

C. When BGP EVPN is used to dynamically establish a VXLAN tunnel, the local and remote VTEPs first establish a BGP EVPN peer relationship and then exchange BGP EVPN routes to transmit VNI and VTEP IP address information. A VXLAN tunnel is then dynamically established between them:In BGP EVPN, VTEPs establish a BGP peer relationship, exchange routes (e.g., Type 2 for MAC/IP or Type 3 for multicast), and share VNI and VTEP IP details, enabling dynamic tunnel setup.TRUE.

D. When configuring a VTEP, you need to create an EVPN Instance in the Layer 2 BDand configure an RD for the local EVPN instance. You do not need to configure an RT:An EVPN Instance (EVI) is created within a BD, and a Route Distinguisher (RD) is configured to make routes unique. However, Route Targets (RTs) are also required to control route import/export between EVPN peers, ensuring proper VNI and route distribution. Stating that RT configuration is not needed is incorrect, as RTs are essential for BGP EVPN operation.FALSE.

Thus,Dis the false statement because RT configuration is necessary in centralized gateway deployment with BGP EVPN.References:Huawei CloudFabric Data Center Network Solution – BGP EVPN Configuration; HCIP-Data Center Network Training – EVPN Gateway Deployment.

Multi-Chassis Link Aggregation Group (M-LAG) is a high-availability technology on Huawei CloudEngine (CE) series switches, where two switches appear as a single logical device to downstream devices. The peer-link between the M-LAG peers synchronizes critical information to ensure seamless failover if one device fails. Let’s evaluate the entries:

A. MAC Address Entries:MAC address tables map device MACs to ports. In M-LAG, synchronizing MAC entries ensures that both switches know the location of connected devices. If one switch fails, the surviving switch can forward Layer 2 traffic without relearning MAC addresses, preventing disruptions.Required.

B. Routing Entries:Routing entries (e.g., OSPF or BGP routes) are maintained at Layer 3 and typically synchronized via routing protocols, not M-LAG peer-link packets. M-LAG operates at Layer 2, and while Layer 3 can be overlaid (e.g., with VXLAN), routing table synchronization is not a standard M-LAG requirement.Not Required.

C. IGMP Entries:IGMP (Internet Group Management Protocol) entries track multicast group memberships. While useful for multicast traffic, they are not critical for basic unicast traffic forwarding in M-LAG failover scenarios. Huawei documentation indicates IGMP synchronization is optional and context-specific, not mandatory for general traffic continuity.Not Required.

D. ARP Entries:ARP (Address Resolution Protocol) entries map IP addresses to MAC addresses, crucial for Layer 2/Layer 3 communication. Synchronizing ARP entries ensures the surviving switch can resolve IP-to-MAC mappings post-failover, avoiding ARP flooding or traffic loss.Required.

Thus,A (MAC address entries) and D (ARP entries)are essential for M-LAG synchronization to maintain traffic forwarding during failover, per Huawei CE switch M-LAG design.References:Huawei CloudEngine Series Switch Configuration Guide – M-LAG Section; HCIP-Data Center Network Training – High Availability Technologies.

VXLAN (Virtual Extensible LAN) is a network overlay technology that extends Layer 2 networks over a Layer 3 underlay, commonly implemented in Huawei’s CloudFabric data center solutions. To enable access to a VXLAN network, service access points (e.g., interfaces or sub-interfaces) must be configured on devices such as switches or routers acting as VXLAN Tunnel Endpoints (VTEPs). The question mentions two access modes: "Layer ? sub-interface" and "binding," with the task to fill in the layer acronym in uppercase letters.

Context Analysis:The missing layer is indicated by a "?" and is part of a sub-interface configuration. In networking, sub-interfaces are typically associated with Layer 3 (e.g., for VLAN tagging or VXLAN integration), where they handle IP routing or mapping to overlay networks.

Access Modes:

Layer 3 Sub-Interface:This mode involves configuring a sub-interface on a Layer 3 device (e.g., a router or Layer 3 switch) to terminate VXLAN tunnels and perform routing. The sub-interface is associated with a VNI (VXLAN Network Identifier) and often uses a Layer 3 protocol (e.g., BGP EVPN) to connect to the VXLAN overlay.

Binding:This likely refers to binding a VNI to a Bridge Domain (BD) or interface, a common practice in Huawei’s VXLAN configuration to map the overlay network to a physical or logical port. This can occur at Layer 2 or Layer 3, but the sub-interface context suggests Layer 3 involvement.

The question’s structure implies the layer number for the sub-interface mode, which isLayer 3in VXLAN contexts for routing and gateway functions. Thus, the acronym (digit) to enter is3.References:Huawei CloudFabric Data Center Network Solution – VXLAN Configuration Guide; HCIP-Data Center Network Training – VXLAN Access Methods.

In Huawei’s CloudFabric Solution, iMaster NCE-Fabric is the SDN controller responsible for managing physical devices and virtual switches (vSwitches). The method of data collection is critical for network monitoring.

SNMP Usage:Simple Network Management Protocol (SNMP) is a traditional method for collecting alarms and logs from network devices. However, Huawei’s modern SDN controllers, including iMaster NCE-Fabric, primarily usetelemetry(e.g., gRPC, NETCONF) for real-time data collection from physical devices and vSwitches. Telemetry provides higher efficiency and granularity compared to SNMP.

CloudFabric Approach:The solution leverages telemetry-based data collection, as documented in FabricInsight and iMaster NCE-Fabric guides, to gather alarms, logs, and performance metrics. SNMP may be supported as a legacy option but is not the primary method in this context.

The statement isFALSE (B)because iMaster NCE-Fabric predominantly uses telemetry, not SNMP, for collecting alarms and logs.References:Huawei CloudFabric Data Center Network Solution – Monitoring and Telemetry; HCIP-Data Center Network Training – Data Collection Methods.

In a network overlay, VXLAN (Virtual Extensible LAN) tunnels extend Layer 2 networks over a Layer 3 underlay, commonly implemented in Huawei’s data center solutions. The endpoints of a VXLAN tunnel are VXLAN Tunnel Endpoints (VTEPs), which encapsulate and decapsulate traffic.

VTEP Roles:VTEPs can be physical switches (e.g., Huawei CloudEngine series), virtual switches (e.g., Open vSwitch on a hypervisor), or routers with VXLAN support. The endpoints are defined by their IP addresses, not their physical nature.

Deployment Flexibility:In modern data centers, VXLAN tunnels often connect physical switches to virtualized environments where VTEPs reside on hypervisors or servers hosting VMs. For example, a VM’s vNIC might connect to a virtual switch (VTEP) that tunnels to a physical switch VTEP. Thus, both endpoints are not always physical switches; one or both can be virtual.

The statement isFALSE (B)because both endpoints of a VXLAN tunnel are not necessarily physical switches; they can include virtual VTEPs in hypervisors or other devices.References:Huawei HCIP-Data Center Network Training – VXLAN Overlay; CloudFabric VXLAN Deployment Guide.

Traditional data center networks (DCNs) often suffer from single points of failure, limited scalability, and traffic bottlenecks. Both M-LAG and stacking address these issues, but their suitability for 24/7 service continuity differs.

M-LAG Benefits:M-LAG (Multi-Chassis Link Aggregation) on Huawei CE switches allows two devices to act as a single logical switch, providing active-active forwarding, high availability, and rapid failover (e.g., via peer-link synchronization). It supports non-stop service during device failures, making it ideal for 24/7 continuity.

Stacking Benefits:Stacking combines multiple switches into a single logical unit, sharing a control plane. While it improves scalability and simplifies management, a stack master failure can disrupt the entire stack unless redundancy is perfectly configured, potentially affecting service continuity.

Comparison:M-LAG’s decentralized design and real-time synchronization offer better fault isolation and recovery compared to stacking, where a master switch failure impacts the stack. Huawei documentation highlights M-LAG’s superiority for high-availability scenarios like 24/7 operations.

The statement isTRUE (A)because M-LAG is indeed a better choice than stacking for ensuring 24/7 service continuity due to its robust failover and redundancy features.References:Huawei CloudEngine Series Switch Configuration Guide – M-LAG vs. Stacking; HCIP-Data Center Network Training – High Availability Solutions.

The tenant service model in Huawei’s data center networks (e.g., CloudFabric with SDN) organizes resources for multi-tenancy. Let’s evaluate each statement:

A. A tenant can apply for independent compute, storage, and network resources:This is true. Tenants in a multi-tenant environment can request isolated compute (VMs), storage (volumes), and network (VLANs/VXLAN VNIs) resources, a core feature of Huawei’s tenant isolation model.TRUE.

B. One logical router is mapped to one VRF:This is true. A Virtual Routing and Forwarding (VRF) instance is associated with a logical router to provide isolated Layer 3 routing for a tenant, a standard practice in Huawei’s network virtualization.TRUE.

C. An EPG can have only one subnet:This is false. An Endpoint Group (EPG) in Huawei’s ACI-like models can span multiple subnets, grouping endpoints (e.g., VMs) based on policies, not limited to a single subnet.FALSE.

D. A subnet supports the access of only one VM:This is false. A subnet can support multiple VMs, as it defines an IP address range for a network segment, not a one-to-one VM mapping.FALSE.

Thus,A and Bare true statements about the tenant service model.References:Huawei CloudFabric Data Center Network Solution – Tenant Model; HCIP-Data Center Network Training – Multi-Tenancy.

In Linux, the operating system is divided intouser space(where applications run) andkernel space(where the OS core functions execute with privileged access to hardware). Let’s evaluate each function:

A. The NIC Driver Sends Data Frames:Network Interface Card (NIC) drivers operate in kernel space, managing hardware interactions like sending and receiving data frames. This is a low-level task requiring direct hardware access, handled by the kernel’s network stack.Included in Kernel Space.

B. Data Encapsulation:Data encapsulation (e.g., adding headers in the TCP/IP stack) occurs in the kernel’s network subsystem (e.g., via the protocol stack like IP or TCP). This process prepares packets for transmission and is a kernel-space function.Included in Kernel Space.

C. Bit Stream Transmission:This refers to the physical transmission of bits over thenetwork, managed by the NIC hardware and its driver in kernel space. The kernel coordinates with the NIC to send bit streams, making this a kernel-space function.Included in Kernel Space.

D. Data Encryption:Encryption (e.g., via OpenSSL or application-level VPNs) typically occurs in user space, where applications or libraries handle cryptographic operations. While the kernel supports encryption (e.g., IPsec in the network stack), the actual encryption logic is often offloaded to user-space tools, not a core kernel function in standard contexts.Not Typically in Kernel Space.

Thus,A, B, and Care functions included in the kernel space, aligning with Linux architecture in Huawei’s DCN context.References:Huawei HCIP-Data Center Network Training – Linux Basics; Linux Kernel Documentation – Kernel vs. User Space.

VXLAN (Virtual Extensible LAN) tunnels are used to encapsulate Layer 2 traffic over a Layer 3 network, a key component in Huawei’s CloudFabric data center solutions. Let’s evaluate each statement:

A. A VXLAN tunnel is identified by a pair of VTEPs:This is true. A VXLAN tunnel is identified by the pair of VXLAN Tunnel Endpoint (VTEP) IP addresses (local and remote), along with the VNI (VXLAN Network Identifier). This ensures unique tunnel identification.TRUE.

B. After a tunnel is established, if one end of the tunnel goes Down, the other end may not go Down:This is true. VXLAN tunnels are unidirectional, and the status of one end does not automatically affect the other unless the underlay network connectivity (e.g., Layer 3 reachability) is lost. The remote VTEP may remain operational if it can still encapsulate/decapsulate traffic.TRUE.

C. For a static tunnel, you need to manually configure the local and remote VNIs:This is true. In a static VXLAN tunnel, administrators must manually configure the VNI and VTEP IP addresses on both ends, as there is no dynamic control plane (e.g., BGP EVPN) to automate the process.TRUE.

D. Dynamic tunnels depend on EVPN Type 5 routes to transmit information:This is false. Dynamic VXLAN tunnels rely on BGP EVPN as the control plane, but Type 5 routes (IP Prefix routes) are specifically used for advertising host IP routes and external network routes, not for general tunnel establishment. Dynamic tunnel setup primarily uses Type 2 (MAC/IP Advertisement) and Type 3 (Multicast) routes to exchange VNI and VTEP information. Type 5 routes are relevant for Layer 3 routing, not the initial tunnel setup.FALSE.

Thus,Dis the false statement because dynamic tunnels depend on EVPN Type 2 and Type 3 routes, not Type 5, for initial establishment.References:Huawei CloudFabric Data Center Network Solution – VXLAN Configuration Guide; HCIP-Data Center Network Training – VXLAN Tunneling.

In Huawei’s spine-leaf DCN architecture, nodes have distinct roles:

A. Spine:The spine nodes form the backbone of the data center, providing high-speed IP forwarding between leaf nodes. They handle east-west traffic with non-blocking connectivity, making them the core backbone nodes.Correct.

B. DC1 leaf:This is not a standard node type; it may be a typo or misnomer. Leaf nodes connect to endpoints, not act as backbones.Incorrect.

C. Service leaf:Service leaf nodes connect to internal services (e.g., servers), not the backbone, focusing on access rather than high-speed forwarding.Incorrect.

D. Border leaf:Border leaf nodes connect to external networks, handling routing, not serving as the internal backbone.Incorrect.

Thus, the answer isA (Spine).References:Huawei CloudFabric Data Center Network Solution – Spine-Leaf Architecture; HCIP-Data Center Network Training – Node Roles.

Reliability in Huawei’s CloudFabric data centers is enhanced through various mechanisms. Let’s evaluate each option:

A. Power supply redundancy:This is true. Redundant power supplies (e.g., dual PSUs) ensure uninterrupted operation during power failures, a key reliability feature.TRUE.

B. M-LAG (Multi-Chassis Link Aggregation):This is true. M-LAG provides high availability by allowing active-active forwarding and failover between switches, enhancing network reliability.TRUE.

C. Monitor Link:This is false. Monitor Link is a Huawei feature for link status monitoring, not a direct reliability enhancement mechanism like redundancy or clustering.FALSE.

D. Controller cluster:This is true. A clustered SDN controller (e.g., iMaster NCE-Fabric) ensures high availability and failover, improving network management reliability.TRUE.

Thus,A, B, and Denhance DC reliability.References:Huawei CloudFabric Data Center Network Solution – Reliability Features; HCIP-Data Center Network Training – High Availability.