（）is the 4th layer of the OSI reference model responsible for reliable network communication between end nodes.

A:Data link layer B:Session layer C:Transport layer D:Application layer

In the data link layer, the data unit is called (71) ．

A:flame B:Packet C:Signal D:APDU

Which OSI layer does a Router operate at

A:the Physical Layer B:the Data Link Layer C:the Transfer Layer D:the Network Layer

Which OSI layer does a bridge operate at

A:the Physical Layer B:the Network Layer C:the Transport Layer D:the Data Link Layer

Which OSI layer does a Bridge operate at ( )

A:the Physical Layer B:the Data Link Layer C:the Transport Layer D:the Network Layer

Transport gateways connect byte streams in the transport layer. Application gateways allow interworking above

A:network layer B:data link layer C:transport layer D:application layer

Which OSI layer are both SLIP and PPP belonged to ( )

A:the Physical Layer B:the Network Layer C:the Data Link Layer D:the Transport Layer

Transport gateways connect byte streams in the transport layer. Application gateways allow interworking above

A:network layer B:data link layer C:transport layer D:application layer