COMPUTER NETWORK (TRANSPORT LAYER)
Transport Layer
o The transport layer is a 4th layer from the top.
o The main role of the transport layer is to provide the communication services
directly to the application processes running on different hosts.
o The transport layer provides a logical communication between application
processes running on different hosts. Although the application processes on
different hosts are not physically connected, application processes use the
logical communication provided by the transport layer to send the messages
to each other.
o The transport layer protocols are implemented in the end systems but not in
the network routers.
o A computer network provides more than one protocol to the network
applications. For example, TCP and UDP are two transport layer protocols
that provide a different set of services to the network layer.
o All transport layer protocols provide multiplexing/demultiplexing service. It also
provides other services such as reliable data transfer, bandwidth guarantees,
and delay guarantees.
o Each of the applications in the application layer has the ability to send a
message by using TCP or UDP. The application communicates by using either
of these two protocols. Both TCP and UDP will then communicate with the
internet protocol in the internet layer. The applications can read and write to
the transport layer. Therefore, we can say that communication is a two-way
process.
, COMPUTER NETWORK (TRANSPORT LAYER)
Services provided by the Transport Layer
The services provided by the transport layer are similar to those of the data link layer.
The data link layer provides the services within a single network while the transport
layer provides the services across an internetwork made up of many networks. The
data link layer controls the physical layer while the transport layer controls all the
lower layers.
The services provided by the transport layer protocols can be divided into five
categories:
o End-to-end
delivery
o Addressing o
Reliable delivery o
Flow control o
Multiplexing
Transport Layer
o The transport layer is a 4th layer from the top.
o The main role of the transport layer is to provide the communication services
directly to the application processes running on different hosts.
o The transport layer provides a logical communication between application
processes running on different hosts. Although the application processes on
different hosts are not physically connected, application processes use the
logical communication provided by the transport layer to send the messages
to each other.
o The transport layer protocols are implemented in the end systems but not in
the network routers.
o A computer network provides more than one protocol to the network
applications. For example, TCP and UDP are two transport layer protocols
that provide a different set of services to the network layer.
o All transport layer protocols provide multiplexing/demultiplexing service. It also
provides other services such as reliable data transfer, bandwidth guarantees,
and delay guarantees.
o Each of the applications in the application layer has the ability to send a
message by using TCP or UDP. The application communicates by using either
of these two protocols. Both TCP and UDP will then communicate with the
internet protocol in the internet layer. The applications can read and write to
the transport layer. Therefore, we can say that communication is a two-way
process.
, COMPUTER NETWORK (TRANSPORT LAYER)
Services provided by the Transport Layer
The services provided by the transport layer are similar to those of the data link layer.
The data link layer provides the services within a single network while the transport
layer provides the services across an internetwork made up of many networks. The
data link layer controls the physical layer while the transport layer controls all the
lower layers.
The services provided by the transport layer protocols can be divided into five
categories:
o End-to-end
delivery
o Addressing o
Reliable delivery o
Flow control o
Multiplexing
