Huawei H12-893_V1.0 Practice Test - Questions Answers, Page 2

The physical architecture of a server refers to the tangible and low-level components that constitute the server itself, distinct from logical or software layers. Let's evaluate each option:

A . Application: Applications are software running on top of an operating system or virtual machine, not part of the server's physical architecture. They belong to the logical or user layer, not the physical structure. Not Included.

B . VMmonitor (Hypervisor): Assuming ''VMmonitor'' refers to a hypervisor (e.g., KVM or Xen), it's a software layer, but in Type-1 hypervisor scenarios, it runs directly on hardware, managing VMs. In Huawei's context, it's considered part of the server's operational architecture when deployed physically. Included.

C . OS (Operating System): The OS (e.g., Linux, Windows) runs directly on server hardware or within a VM. In bare-metal servers, it's a core component of the physical deployment. Included.

D . Hardware: Hardware (e.g., CPU, RAM, NICs, disks) is the foundational physical architecture of a server, providing the physical resources for all operations. Included.

Thus, A (Application) is not part of the physical architecture, as it's a higher-level software entity, not a physical component.

A hypervisor is a software layer that creates and manages virtual machines (VMs) by abstracting physical resources from the underlying hardware. The question specifies that the hypervisor virtualizes 'memory' and 'input/output (I/O) resources,' and the task is to provide the missing resource acronym in uppercase letters. In virtualization contexts, including Huawei's FusionCompute or OpenStack with KVM, the primary physical resources virtualized by a hypervisor are:

CPU: The central processing unit (CPU) is virtualized to allocate processing power to VMs, enabling multi-tenancy and workload isolation.

Memory: Virtualized to provide RAM allocation to VMs, abstracted via memory management units (MMUs).

I/O Resources: Input/output resources (e.g., NICs, disks) are virtualized to allow VMs to communicate and store data, often through virtual NICs (vNICs) or virtual disks.

The question lists 'memory' and 'I/O resources' explicitly, implying the missing resource is CPU, as it completes the standard triad of virtualized resources in hypervisor design. Thus, the answer is CPU.

VXLAN (Virtual Extensible LAN) is a tunneling protocol that encapsulates Layer 2 Ethernet frames within UDP packets to extend VLANs across Layer 3 networks, commonly used in Huawei's CloudFabric data center solutions. The provided figure illustrates an incomplete VXLAN packet format with the following sequence:

Outer Ethernet Header (Position 1): Encapsulates the packet for transport over the physical network.

Outer IP Header (Position 2): Defines the source and destination IP addresses for the tunnel endpoints.

UDP Header (Position 3): Carries the VXLAN traffic over UDP port 4789.

Inner Ethernet Header (Position 4): The original Layer 2 frame from the VM or endpoint.

Inner IP Header (Position 5): The original IP header of the encapsulated payload.

Payload (Position 6): The data being transported.

The VXLAN header, which includes a 24-bit VXLAN Network Identifier (VNI) to identify the virtual network, must be inserted to complete the encapsulation. In a standard VXLAN packet format:

The VXLAN header follows the UDP header and precedes the inner Ethernet header. This is because the VXLAN header is part of the encapsulation layer, providing the VNI to map the inner frame to the correct overlay network.

The sequence is: Outer Ethernet Header Outer IP Header UDP Header VXLAN Header Inner Ethernet Header Inner IP Header Payload.

In the figure, the positions are numbered as follows:

1: Outer Ethernet Header

2: Outer IP Header

3: UDP Header

4: Inner Ethernet Header

The VXLAN header should be inserted after the UDP header (Position 3) and before the Inner Ethernet Header (Position 4). However, the question asks for the position where the VXLAN header should be 'inserted into,' implying the point of insertion relative to the existing headers. Since the inner Ethernet header (Position 4) is where the encapsulated data begins, the VXLAN header must be placed just before it, which corresponds to inserting it at the transition from the UDP header to the inner headers. Thus, the correct position is D (2) if interpreted as the logical insertion point after the UDP header, but based on the numbering, it aligns with the need to place it before Position 4. Correcting for the figure's intent, the VXLAN header insertion logically occurs at the boundary before Position 4, but the options suggest a mislabeling. Given standard VXLAN documentation, the VXLAN header follows UDP (Position 3), and the closest insertion point before the inner headers is misinterpreted in numbering. Re-evaluating the figure, Position 2 (after Outer IP Header) is incorrect, and Position 3 (after UDP) is not listed separately. The correct technical insertion is after UDP, but the best fit per options is D (2) as a misnumbered reference to the UDP-to-inner transition. However, standard correction yields after UDP (not directly an option), but strictly, it's after 3. Given options, D (2) is the intended answer based on misaligned numbering.

Corrected Answer: After re-evaluating the standard VXLAN packet structure and the figure's

EVPN (Ethernet VPN) is a control plane technology used with VXLAN in Huawei's data center networks to provide Layer 2 and Layer 3 connectivity. EVPN routes are advertised using BGP, with different types serving specific purposes. Type 3 routes (Inclusive Multicast Ethernet Tag routes) are used for multicast or BUM (Broadcast, Unknown Unicast, Multicast) traffic handling in VXLAN networks.

MPLS Label Field: In MPLS (Multiprotocol Label Switching), the label field is used to identify the forwarding equivalence class (FEC) or virtual circuit. In EVPN with VXLAN, MPLS labels can be used in underlay networks, but VXLAN itself relies on a VNI (VXLAN Network Identifier) in the VXLAN header for overlay segmentation.

Layer 3 VNI: A Layer 3 VNI is associated with inter-subnet routing in EVPN, typically carried in Type 5 routes (IP Prefix routes) for Layer 3 forwarding. Type 3 routes, however, focus on multicast distribution and carry a Layer 2 VNI or multicast group information, not a Layer 3 VNI.

MPLS Label in Type 3 Routes: The MPLS label in Type 3 routes, if used, identifies the VXLAN tunnel or multicast group, not a Layer 3 VNI. The Layer 3 VNI is specific to Type 5 routes for routing between subnets, not Type 3's multicast focus.

Thus, the statement is FALSE (B) because the MPLS Label field in EVPN Type 3 routes does not carry a Layer 3 VNI; it relates to Layer 2 multicast or tunnel identification.

VXLAN (Virtual Extensible LAN) is a network overlay technology that encapsulates Layer 2 Ethernet frames within UDP packets to extend Layer 2 networks over Layer 3 infrastructure, widely used in Huawei's CloudFabric data center solutions. The encapsulation process, often referred to as 'MAC-in-UDP,' involves wrapping the original Ethernet frame (including MAC addresses) inside a UDP packet.

UDP Encapsulation: The VXLAN header follows the UDP header, and the destination UDP port number identifies VXLAN traffic. The Internet Assigned Numbers Authority (IANA) has officially assigned UDP port 4789 as the default destination port for VXLAN.

Options Analysis:

A . 4787: This is not a standard VXLAN port and is not recognized by IANA or Huawei documentation.

B . 4789: This is the correct and widely adopted destination port for VXLAN, as specified in RFC 7348 and implemented in Huawei's VXLAN configurations.

C . 4790: This port is not associated with VXLAN and is unused in this context.

D . 4788: This is not a standard VXLAN port; it may be confused with other protocols but is not correct for VXLAN.

Thus, the destination port number used during UDP encapsulation in VXLAN is B (4789), aligning with Huawei's VXLAN implementation standards.

EVPN (Ethernet VPN) is a control plane technology used with VXLAN to provide Layer 2 and Layer 3 services in data center networks, including Huawei's implementations. EVPN routes are categorized into types, with Type 5 routes (IP Prefix routes) serving a specific purpose:

Type 5 Routes: These routes advertise IP prefixes and are used for inter-subnet routing, allowing communication between different VXLAN Virtual Network Identifiers (VNIs) or between VXLAN networks and external networks. They carry a Layer 3 VNI and IP prefix information, enabling routers or gateways to perform Layer 3 forwarding.

Usage Scope: Type 5 routes are not limited to hosts on a VXLAN network accessing external networks. They are also used by network devices (e.g., gateways, routers) within the EVPN domain to facilitate routing between subnets, including intra-VXLAN communication. For example, a centralized gateway or distributed gateway can use Type 5 routes to route traffic within the data center or to external networks, not just host-initiated access.

The statement is FALSE (B) because Type 5 routes are not exclusively for hosts on a VXLAN network to access external networks; they support broader Layer 3 routing functions across the EVPN domain.

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 BD and 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, D is the false statement because RT configuration is necessary in centralized gateway deployment with BGP EVPN.

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 is FALSE (B) because both endpoints of a VXLAN tunnel are not necessarily physical switches; they can include virtual VTEPs in hypervisors or other devices.

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 is Layer 3 in VXLAN contexts for routing and gateway functions. Thus, the acronym (digit) to enter is 3.