Virtual Local Area Networks (VLANs) logically divide a physical LAN into multiple broadcast domains.

According to the Huawei HCIA-Cloud Computing technical manual, the statement is TRUE. A Virtual Local Area Network (VLAN) is a technology used at the Data Link Layer (Layer 2) to partition a physical switch or a network into multiple logical segments. In a traditional local area network, all devices connected to the same set of switches belong to a single broadcast domain. This means that any broadcast packet (such as an ARP request) is sent to every single port, which can lead to "broadcast storms" and security vulnerabilities as the network scales.

VLAN technology solves this by logically dividing the physical infrastructure. Each VLAN acts as its own independent broadcast domain. Even if two hosts are physically plugged into the same switch, if they belong to different VLANs (e.g., VLAN 10 and VLAN 20), they cannot communicate directly at Layer 2. A broadcast sent by a host in VLAN 10 will only be received by other hosts in VLAN 10. This isolation provides two major benefits in a cloud environment:SecurityandEfficiency. Security is enhanced because traffic from one department or tenant is logically separated from others, preventing unauthorized sniffing. Efficiency is improved by reducing unnecessary broadcast traffic, which preserves bandwidth and CPU cycles on the connected hosts.

In Huawei’s virtualization platform,FusionCompute, VLANs are a critical component of "Distributed Virtual Switches" (DVS). When administrators create port groups for Virtual Machines, they often assign a VLAN ID to that group. This ensures that the virtual machines are logically placed in the correct network segment. For hosts in different VLANs to communicate, a Layer 3 device (like a router or a Layer 3 switch) must perform "inter-VLAN routing." This strict separation at the logical level is what allows cloud providers to host multiple tenants on shared physical hardware securely.

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