The document summarizes data communication networks and their architectures. It discusses the 7 layers of the OSI model from the physical layer to the application layer. It then describes 4 common network topologies: bus networks with devices connected along a single spine; branching networks with branches extending from a central spine; star networks with a central connecting node; and ring networks with devices connected in a circular configuration to form a closed loop.

1. DATA COMMUNICATION
NETWORK
By :-
HARSHKUMAR MANILAL PATEL
Lukhdhirji Engineering College
1st ME Power System
Enrollment No.:-130310737010

2.  Network Architectures
• Application Layer
• Presentation Layer
• Session Layer
• Transport Layer
• Network Layer
• Data Link Layer
• Physical Layer
 Typical Network Topologies
• Bus Network
• Branching Network
• Star Network
• Ring Network
Content:-

3. Network Architectures
• All electronic data communications equipment today use one
or more layer of the 7-layer OSI model.
• Each application may use one or all of the layers.
• The lowest level sa the simplest lavels,and they will use in
almost every application.
• The upper 4 lavels are more complex and are only use in more
sophisticated systems.
• This that you may work with only the first three or four layers
most of time.

4. 7 APPLICATION
6 PRESENTATION
5 SESSION
4 TRANSPORT
3 NETWORK
2 DATA LINK
1 PHYSICAL
The 7-layer OSI model

5. • This layer is the physical layer and it has the job of moving the
electrical signal from one point to another.
• This layer include the wire of cable through which data are
sent.
• This layer also includes the electrical on-off pulse that move
through the wire.
• This layer is only concerned with the physical medium of
transporting the signal from one point to another.
• This layer does not provide any error detection, error control,
or sequencing of data.
• This layer include wire specifications and cable termination
specifications.
1. The Physical Layer

6. • The data layer combines with the physical layer to make more
reliable system in that it add error detection and error
recovery methods.
• The rules for this layer are usually called protocols.
• This layer will include a means to start and stop the data flow,
away to package each part of the data.
• A means of sequencing when data are sent and when they are
received, a means to acknowledge that data have been
received.
• A means of providing timing that includes when the data are
being sent and how long to wait if data have not arrived.
2. The Data Link Layer

7. • The primary function of the network layer is to provide a
delivery mechanism for the transport layer.
• This use when the unit that is connected to the data
communications system is part of a multiple-unit network
rather than one single unit connected to only one other single
unit.
• The network layer use a combination of hardware and
software.
• Provide protocols like the x.21.x.25, and x.75.
• This also use when one network must interface with other
network.
3. The Network Layer

8. • The transport layer provides connections from one network to
another.
• Also provides a means of keeping the upper layers from
knowing what the lower layers are doing.
• This is the layer that begins to be different in various type of
network.
• With this possible to use a variety of different networks
because they are fundamentally similar in first three layer.
• In this layer and upper layers, the syatem tend to become very
complex and may have a variety of differences.
4. The Transport Layer

9. • The session layer establishes sessions between user,
maintains the sessions between users, terminates the
sessions between users.
• The major function of this layer also includes connections of
two separate open systems.ISO 8326 and CCITT.X212 are
standards for the session layer.
• When one unit on one network requests data from a unit on a
second network, the session layer directs the transport layer
to make proper connection.
• And regulate the flow of data smoothly interface the
connections and data flow between the two networks.
5. The Session Layer

10. • This layer transforms data information so that one network
can pass information to or receive information from another
network.
• The protocols for this layer are contained in ISO 8823 and
CCITT X.226.
• This layer works closely with the session layer to make the
connection between system works smoothiy.
• This layer is vital if you want to have the networks open to the
largest number of different users.
6. The Presentation Layer

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2
PLC
1
PLC
4
PLC
3
PLC
6
PLC
5
Shipping Receiving
Office
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Factory
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Quality ControlAccounting Process Engineering
Production Supervisor’s
Computer
Maintenance Supervisor’s
Computer

12. • This layer provides the functions of making all of the other
layers compatible when users must interconnect between
multiple network.
• The protocols in the application layer provide this function.
7. The Application Layer

13. Typical Network Topologies
• Local area networks can be classified as baseband or
broadband networks.
• A baseband network is usually limited to equipment that is
connected over short distances.
• A broadband network depends on multiplexing techniques to
split the network into multiple channels.

14. • Four Types Of network Topologies that are commonly use in
industrial data communications systems.
1. Bus
2. Branching
3. Star
4. Ring
Types Of Network Topologies

15. • This type of network is identified by one long spine with user
devices connected along the length of the network.
1. Bus Network
Bus Network

16. • Branching network is show in fig.
• The tree network is identified by one long spine and the
branches that flow from the spine.
• Each branch can also have branches.
2. Branching Network
Branching Network

17. • The star network is identified by a central node on the
network with all other branches of the network emanating
from the center node.
• The computer at the end of each branch can fail without
harming data that are passed to other branches.
• If the computer that acts as the central node fails, the entaire
network will become disabled.
3. Star Network

18. Star Network

19. • The ring network is identified by a main spine that is closed in
the shape of a ring.
• In both variations, data information flows in only one
direction around the ring.
• The first variation of this type of network shows the main
network spine connected in a circle and each node is tap off
the main spine, much like the bus network.
• The second variation of the ring network shows each tap as an
integral part of the ring.
4. Ring Network

20. Ring Network

21. Thank You