Which term is always a reference point between a subscriber network and a service provider?

• A. SD-WAN UNI
• B. PVC
• C. UNI
• D. TVC

Answer: (C)

The key idea is the boundary between the customer’s network and the service provider’s network. This boundary is called the User-Network Interface, or UNI. It designates where the subscriber’s responsibilities end and the provider’s responsibilities begin, and it’s the reference point used for provisioning, SLAs, and fault isolation. In SD-WAN contexts you’ll see the SD-WAN-specific version called SD-WAN UNI, but the universal reference point remains UNI.

PVC and TVC are specific circuit concepts inside the provider’s network used for virtual connections, not the demarcation point between subscriber and provider.