Which technology uses permanent virtual connections in its terminology?

ATM, or Asynchronous Transfer Mode, is the technology that uses the term "permanent virtual connections" in its terminology. In ATM networks, virtual connections refer to paths that data can take through the network, and these can be either permanent or switched. Permanent Virtual Connections (PVCs) are tightly defined connections that are set up in advance and remain established for ongoing communication. This differs from switched virtual connections (SVCs), which can be set up on-the-fly as needed.

The usage of PVCs in ATM is particularly key for applications needing constant bandwidth, such as voice and video traffic. This form of connection allows for predictable performance characteristics, valuable in networks where quality of service is crucial.

In contrast, technologies such as Ethernet, Wi-Fi, and Token Ring primarily rely on different methods of data transmission and connection establishment, and they do not specifically utilize the terminology of permanent virtual connections. Ethernet works on a frame-based transmission using a shared medium, Wi-Fi is based on wireless communication standards without the concept of virtual connections, and Token Ring employs a token-passing protocol to manage access to the network. Hence, ATM stands out with its specific terminology and architecture related to permanent virtual connections.