In cloud environments, virtual machines (VMs) connect to virtual networks to enable communication. Identifying the network to which a VM interface is connected is essential for proper configuration and isolation. Let’s analyze each option:

A. virtual network ID

Correct:Thevirtual network IDuniquely identifies the virtual network to which a VM interface is connected. This ID is used to logically group VMs and ensure they can communicate within the same network while maintaining isolation from other networks.

B. machine access control (MAC)

Incorrect:The MAC address is a hardware identifier for a network interface card (NIC). While it is unique to each interface, it does not identify the network to which the VM is connected.

C. Virtual Extensible LAN (VXLAN)

Incorrect:VXLAN is a tunneling protocol used to create overlay networks in cloud environments. While VXLAN encapsulates traffic, it does not directly identify the network to which a VM interface is connected.

D. virtual tunnel endpoint (VTEP)

Incorrect:A VTEP is a component of overlay networks (e.g., VXLAN) that encapsulates and decapsulates traffic. It is used to establish tunnels but does not identify the virtual network itself.

Why Virtual Network ID?

Logical Isolation:The virtual network ID ensures that VMs are logically grouped into isolated networks, enabling secure and efficient communication.

Scalability:Virtual networks allow cloud environments to scale by supporting multiple isolated networks within the same infrastructure.

JNCIA Cloud References:

The JNCIA-Cloud certification emphasizes understanding virtual networking concepts, including virtual networks and their identifiers. Virtual network IDs are fundamental to cloud architectures, enabling multi-tenancy and network segmentation.

For example, Juniper Contrail uses virtual network IDs to manage connectivity and isolation for VMs in cloud environments. Proper configuration of virtual networks ensures seamless communication and security.