Application layer, and Transport layer.
Find information about transport layer and its functions at wikipedia: http://en.wikipedia.org/wiki/Transport_Layer#Transport_Layer_functions
Transport layer and Network layer.
Layer 4 transport
False.
TCP and UDP
The two that are most commonly used are called TCP and UDP.
No. It is the Data Link layer that IEEE has divided into two sublayers. The Data Link layers are Logical Link Control and Media Access Control.
physical & data link layers
two applications communicating the data
because in the data link layer two routers communitate directly via a physical channel , whereas at the transport layer this physical channel is replaced by the entire subnet. In the data link layer ,it is not necessary for a router to specify which router it wants to talk to each outgoing line uniquely specifies a panicular router . In the transport layer explicit addressing of destinations is required.
There are actually two different GTP protocols. GTP (Go Text Protocol) is basically an application layer protocol, although the definition is a bit fuzzy. GTP (GPRS Tunneling Protocol) is a transport layer protocol that is used in conjunction with another transport layer protocol (TCP or UDP).
UDP