Correct Option: A. Virtual Local Area Networks (VLANs)
VLANs are widely used in cloud and traditional environments to provide logical separation of network traffic. In a multi-tenant cloud environment, VLANs help ensure that one customer's network traffic is isolated from another’s, providing a key layer of segmentation and security.
From CSA Security Guidance v4.0 – Domain 7: Infrastructure Security:
“To isolate tenants in multi-tenant environments, cloud providers often rely on mechanisms such as VLANs, VXLANs, or other software-defined networking technologies. VLANs ensure that different customer environments remain logically separated even though they share the same physical infrastructure.”
— Domain 7: Infrastructure Security, CSA Security Guidance v4.0
Why the Other Options Are Incorrect:
B. Resource pooling➤ Refers to shared infrastructure in the cloud. It enables multi-tenancy but does not enforce separation between tenants.
C. Software-defined networking (SDN)➤ SDN provides flexibility and programmability in networking. While it can support separation, VLANs are the actual mechanism used for enforcing it.
D. Elasticity➤ Elasticity refers to scaling resources up/down based on demand. It has nothing to do with tenant isolation or network separation.
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