1. Public Switched Telephone Network (PSTN)

2. Communication networking
Networking modes
Connection oriented
Connectionless
Switching modes
Circuit switching
Packet switching

3. Connection oriented Pros Cons Switching Modes Guaranteed service
Efficient bandwidth utilization
Cons
Delay in connection setup
Switching
Circuit switching – PSTN, SDH/SONET, DWDM
Packet switching – X.25, Frame Relay, ATM
Modes
Depending on estimated traffic- PVC
Depending on demand- SVC

4. Connection oriented

5. Connectionless

6. Data Communications

7. Evolution of Data Networking Architecture
Time
Architecture
1970s
Standalone mainframes
Early 1980s
Networked mainframes
Standalone workstations
Early to late 1980s
Local area networking
Mid-1980s to mid-1990s
LAN internetworking
Mid-1990s
Internet commercialization
Mid- to late 1990s
Application-driven networks
Late 1990s
Remote-access workers
Early 2000s
Home area networking
Mid-2000s
Personal area network and the Internet

8. Data Traffic Communications
Applications
Web surfing and s
Transaction processing
File transfer
Interactive computing and information retrieval

9. Data Flow Aspects of data flow
DTE – DCE – Transmission Channel – Physical Interface
Modems and modulation
Data transmission types
Simplex
Half duplex
Full duplex
Coding scheme
Data transmission modes
Asynchronous
Synchronous
Error control

10. DTE, DCE, Tx. DTE DCE Tx and Rx info Error control
Establishes, maintains and terminates the session between DTE and the Channel
Channel coding
PBX, Modem

11. Modems and modulation
Conversion of digital to analog for Tx medium

12. Modulation schemes Single-carrier Multicarrier
Sub-band divided single carrier

13. Scheme
Description
Single carrier
2B1Q
4 levels of amplitude for 2 bits/Hz. ISDN, HDSL
64-QAM
Modulates both amplitude and phase. 6 bits/Hz
256-QAM
?? Bits/Hz
16-QAM
?? bits/Hz
QPSK
Phase modulation. Over the air transmission, broadcast and satellite channels
CAP
Carrier amplitude phase modulation. Combination of amplitude and phase modulation
Multicarrier
OFDM
Orthogonal frequency division multiplexing. For wireless broadcast and broadband solutions a, g,
DMT
Discrete multitone. Variable spectral efficiency for each sub-bands. DSL

14. OSI Reference Layer