None, they communicate to the layer 7, however they do not operate at that layer(application)
7
email messages can be sent directly from user to user over the internet, whereas word processing software operates offline
datalink layer
The application layer (layer 7) is responsible for file transfer operations.
Network layer
TCP operates at transport layer
datalink layar
Layer 3-7
IGMP
generally layer 4, but SOCKS operates at layer 5, which allows it to work well with applications
Layer 7, Aplication
router operates on Layer 3 and can be used as a switch
FTP operates in application layer of ISO OSI layered model.