Data Communications and Networking

Data Communications and Networking

1. Network is a set of devices (often referred to as nodes) connected by communication links.

2. Network Criteria

   • 1- Performance
     • Depend on : 1- Number of user 2- Type of transmission media 3- Capabilities of connected H.W and the efficiency of SW
   • 2- Reliability
   • 3- security

3. Physical Structures

   • 1- Type of connection
     • point to point
     • multi point
   • 2- physical topology
     • mesh
       • 1- point-to-point link 2- have n-1 (I/O) ports for each device 3- has n(n-1)/2 physical connection to link n devices.
     • star
       • 1- point-to-point link 2- has n physical connection to link n devices.
       • tree topology
     • ring
       • 1- point-to-point link 2 - has n physical connection to link n devices.
     • bus
       • 1- multi point link 2- has one backbone and n drop lines
     • hybrid topology

4. Categories of Networks

   • LAN
   • MAN
   • WAN
   • determined by: 1- size 2- ownership 3-distance it cover 4- physical architecture.

5. By : Sarah AlNofal

6. Interconnection of Networks

   • Internet Service Providers (ISPs)
     • There are four levels of ISP :
       • 1- international service providers
       • 2- national service providers
       • 3- regional service providers
       • 4- local service providers
   • Protocols
     • Key elements of a protocol: Syntax, semantics and timing
   • Standards
     • Two categories: 1.De fact 2.De jure
   • Standards Organization
     • 1.International Organization for Standardization (ISO) 2. International Telecommunication Union Telecommunication standard sector ( ITU-T) 3. American National Standards Institute (ANSI) 4. Institute of Electrical and Electronics Engineers (IEEE) 5. Electronic Industries Association (EIA)

7. Data Communication

   • The Effectiveness of data communication depends on : 1- Delivery 2- Accuracy 3- Timeliness 4- Jitter
   • It is have Five components : 1- message 2- sender 3- receiver 4- transmission medium 5- protocol
   • Data Representation
     • The Data can be either: Text, numbers, images, audio, or video , each type have its own represent
   • Direction of Data Flow
     • 1-Simplex, 2- half duplex 3- full duplex