Understanding User Isolation in the Same VLAN

In a traditional VLAN,all devices within the same VLAN can communicateunless additional security policies are applied.To isolate users within the same VLAN, the following technologies can be used:

✅B. Port Isolation (Private VLAN or Layer 2 Isolation)

Prevents communication between ports within the same VLAN.

Common in enterprise and campus networksto improve security.

Example:Isolating guest users from employees within the same VLAN.

✅C. IPSG (IP Source Guard)

BlocksIP address spoofingwithin the same VLAN.

UsesDHCP snooping binding tableto verify whether a device is using anauthorized IP address.

✅D. Ethernet Port Security

Limits the number of MAC addressesallowed per port.

Preventsunauthorized devicesfrom communicating within the VLAN.

❌A. Super VLAN (Incorrect Choice)

Super VLANgroups multiple VLANs under a single Layer 3 gateway, but it doesnot provide isolationwithin the same VLAN.

Real-World Application:

Public Wi-Fi Networks:Ensures thatusers within the same VLAN cannot communicatewith each other.

Enterprise Security:Prevents unauthorized access or attacks withinshared VLANs.

✅Reference:Huawei HCIE-Datacom Guide – VLAN Security and User Isolation Technologies