Final answer:
Neither Routers, Switches, Bridges, nor Hubs operate at the transport layer. These devices work at different layers of the OSI model such as network, data link, and physical layers respectively. A Gateway would be an example of a device associated with the transport layer.
Step-by-step explanation:
The transport layer is an important concept in network architecture, responsible for the logical communication between applications on different machines in a network. When looking at devices specifically associated with this layer, one should think about the devices that handle end-to-end communication and can facilitate transport layer functions such as segmentation, reassembly, and error checking.
Among the options given:
- Router (1) operates at the network layer, which is responsible for determining the optimal path for data transmission.
- Switch (2) and Bridge (3) work at the data link layer, helping to forward data and isolate traffic within LAN segments.
- Hub (4) operates at the physical layer, primarily acting as a basic connection point for devices in a network.
None of the listed devices operates specifically at the transport layer; they work at other layers of the OSI model. However, if the list included a Gateway, which can operate at higher layers, including the transport layer, it would be a suitable example.