The X.25 standard specifies protocols at the Physical, Data Link, and Network Layers of the OSI Model.
ATM
none of the above
The NIC operates on Layer 2 (Data Link Layer) of the OSI Model.
Network layer
generally layer 4, but SOCKS operates at layer 5, which allows it to work well with applications
TCP operates at Layer 4 which is Transport of the OSI Model!
FTP operates in application layer of ISO OSI layered model.
Which? Where are the Options?WAN Technologies operate & involve Layer1, Layer2 & Layer3 of OSI Model. Example of WAN Technology Protocols are Frame Relay, ATM & X.25 protocols.
Router works in Network Layer of OSI model
If you mean the MAC address, that's a layer-2 concept.
Routers and layer 3 switches work at Layer 3 of OSI model.
IP operates at layer 3, this is the NETWORK LAYER in the OSI Model. Network+ Guide to Networks Fifth Edition Ch02, pg56, Figure 2-7
It operates on the data link layer of the OSI model (level 2). The switch creates a separate collision domain for each port. Although some switches operate on level 3 of the model and are called multi-layer switches.