Defining Data Communication needs, Transmission Hierarchy, Optical Networks: SONET/SDH standard, Architecture, Format, Hardware, Configuration, advantages

1. Module 1
Data Communication
By: Ms. Pradnya Saval

2. Contents
• Defining Data Communication
• Transmission Hierarchy
• Optical Networks:
• SONET/SDH Architecture
• SONET Structure
• SONET Format
• SONET Hardware

3. Data Communication
• Data communications refers to the transmission of this digital data between
two or more computers and a computer network or data network is a
telecommunications network that allows computers to exchange data.
• The physical connection between networked computing devices is
established using either cable media or wireless media.
• The best-known computer network is the Internet.

4. Need of Data Communication
• Increased LAN and application interconnectivity between departments, customers,
and suppliers.
• The movement of mainframe applications to a client-server architecture.
• The movement of applications on a network.
• People can communicate and share information virtually instantaneously across the
entire globe.
• Education and business concerns can take place no matter where the individual
parties are located.

5. Basics of a Network
• Elements of a network:
• Station
• Routers
• Categories
• LAN
• MAN
• WAN
• Topology
• Bus
• Ring
• Star
• Mesh
• Transmission Media
• Guided Media
• Twisted Pair
• Coaxial
• Fibre Optic
• Unguided Media
• Radiowaves
• Micowaves
• Infrared

6. What is an Optical Network?
• An Optical Network is basically a communication network used for the
exchange of information through an optical fiber cable between one end to
another.
• It is one of the quickest networks used for data communication.
• The data signal through an optical fiber is transmitted in the form of light
pulses. So, optical networks are used in order to have optical signal
transmission.

7. Advantages of Optical Network
• Ease of transmitting.
• Permits large data carrying capacity and longer distance transmission than
other cables.
• Low production cost of the cable.
• Supports high bandwidth.
• Signal can be transmitted to longer distances.
• Networking system is more flexible than other transmission systems.

8. SONET - Introduction
• Synchronous Optical Network
• Enhanced version: Synchronous Digital Hierarchy
• SONET is used as a transport network to carry loads from other WANs.
• A standard to be used for fiber optics
• It is a technology for service providers to internationally standardize and
control broadband network transport through common fiber interface
called as midspan meet.

9. Advantages of SONET/SDH
• Reduction of equipment's needed.
• Increased network reliability and availability.
• Centralized fault isolation and management of payload (traffic carried)
• Allows easy access for switching and multiplexing
• Flexible architecture able to accommodate future requirements.

10. Transmission Methods
• Synchronous
• Plesiochronous
• Asynchronous
• SONET/SDH is a synchronous network using synchronous TDM
multiplexing.
• All clocks in the system are locked to a master clock.

11. SONET Architecture
• The architecture of SONET includes:
• Signals
• Devices
• Connections

12. SONET Signals
• SONET defines a hierarchy of electrical signaling levels called as
synchronous transport signals (STSs).
• Each STS level (STS-1 to STS-192) supports certain data rate specified in
megabits/sec.
• Corresponding optical signals are called as Optical carriers (OCs).
• SDH specifies a similar system called as synchronous transport module
(STM).

13. SONET data rates

14. SONET Devices

15. SONET Connections
• The devices in SONET are connected using the following connections:
• Sections
• Lines
• Paths

16. SONET Layers
• The SONET standard includes four functional layers:
• Path
• Line
• Section
• Photonic (physical)

17. SONET Frame Format

18. STS-1 frames in Transmission

19. SONET Frame Format - Key Points
• A SONET STS-n signal is transmitted at 8000 frames per second.
• Each byte in a SONET frame can carry a digitized voice channel.
• In SONET, the data rate of an STS-n signal is n times the data rate of an
STS-1 signal.
• In SONET, the duration of any frame is 125 μs.

20. SONET Frame Format (Cont..)
• Example1: Find the data rate of an STS-1 signal.
• Solution: STS-1, like other STS signals, sends 8000 frames per second. Each
STS-1 frame is made of 9 by (1 × 90) bytes. Each byte is made of 8 bits. The
data rate is:

21. SONET Frame Format (Cont..)
• Example2: Find the data rate of an STS-3 signal.
• Solution: STS-3, like other STS signals, sends 8000 frames per second. Each
STS-3 frame is made of 9 by (3 × 90) bytes. Each byte is made of 8 bits. The
data rate is:

22. SONET Frame Format (Cont..)
• Example3: What is the duration of an STS-1 frame? STS-3 frame? STS-n
frame?
• Solution: In SONET, 8000 frames are sent per second. This means that the
duration of an STS-1, STS-3, or STS-n frame is the same and equal to
1/8000 s, or 125 μs.

23. STS-n Frame Format

24. Section Overhead in STS-n Frame Format

25. Line Overhead in STS-n Frame Format

26. Path Overhead in STS-n Frame Format