• Network infrastructure is the hardware and software resources of an entire network which enable network connectivity, communication, operations and management of an enterprise network.
• It provides the communication path and services between users, processes, applications, services and external networks/the internet.
• Network infrastructure is typically part of the IT infrastructure found in most enterprise IT environments. The entire network infrastructure is interconnected, and can be used for internal communications, external communications or both.
• A typical network infrastructure includes:
  • Networking Hardware
    • Routers
    • Switches
    • LAN Cards
    • Wireless Routers
    • Cables
  • Network Services
    • Satellite
    • Wireless Protocols
    • IP Addressing
  • Networking Software
    • Network Operations and Management
    • Operating System
    • Firewall
    • Network Security Applications
• There are two type of transmission technology that are in use
  • Broadcast links
  • point to point link
• Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable.
• For data communications to occur, the communicating devices must be part of a communication system made up of a combination of hardware (physical equipment) and software (programs).

The effectiveness of a data communications system depends on four fundamental characteristics:
delivery, accuracy, timeliness, and jitter

1. Delivery: The system must deliver data to the correct destination. Data must be received by the intended device or user and only by that device or user.
2. Accuracy: The system must deliver the data accurately. Data that have been altered in transmission
   and left uncorrected are unusable.
3. Timeliness: The system must deliver data in a timely manner.
4. Jitter: Jitter refers to the variation in the packet arrival time. It is the uneven delay in the delivery of
   audio or video packets. For example, let us assume that video packets are sent every 30 millisecond. If
   some of the packets arrive with 30-ms delay and others with 40-ms delay, an uneven quality in the video
   is the result.