Professor messer networking fundamentals

Networking Concepts

Encapsulation and Decapsulation

  • Encapsulation: The process of embedding application data with headers at various communication layers before transmission.

    • Application Layer: Starts with the original application data.

    • Transport Layer: Adds a TCP header to the application data.

    • Internet Layer: Further encapsulates data by adding an IP header.

    • Link Layer: Adds frame headers and trailers, preparing data for network transmission.

  • Decapsulation: The reverse process that occurs at the receiving end.

    • Data is unwrapped layer by layer:

      1. Frame header is removed at the link layer.

      2. IP header is removed at the Internet layer.

      3. TCP header is removed, revealing the original application data, ready for processing.

Communication Layers in the TCP/IP Model

  • Layers Identified:

    • Application Layer

    • Transport Layer

    • Internet Layer

    • Link Layer

  • Each layer adds specific headers relevant to its function, crucial for data transmission over networks.

Types of Networks

Baseband Networks

  • Definition: A type of network using a single cable to send digital signals, utilizing the total available bandwidth.

    • Can use copper or fiber as transmission medium.

    • Usage of Bandwidth: 100% of bandwidth is consumed when any signal is sent.

    • Bidirectional Communication: Allowed but not simultaneous; devices must take turns when communicating.

    • Standard in Ethernet communication: includes 100Mbps and 1Gbps.

Broadband Networks

  • Definition: Allows multiple signals to be sent over the same medium, operating on different frequencies.

    • Supports simultaneous communication across various channels and bidirectional communication.

    • Examples: Cable modems for internet, combination of internet, television, and voice signals.

Data Transmission Metrics

Baud Rate vs. Bit Rate

  • Baud Rate: Measures the number of signal changes per second in a modem connection, indicating how many symbols can be communicated.

    • Bit Rate: Refers to the total number of bits transmitted over a period of time.

    • Analogy: Compare baud rate to train carriages (number of signal changes), while bits (passengers) indicate total data transmitted.

Wavelength in Networking

  • Definition: The length over which a wave (signal) repeats, essential for communication frequency tuning.

    • Higher frequency leads to shorter wavelengths:

      • Example: 2.4GHz wireless network has wavelengths about 12 centimeters.

    • Fiber Optics Wavelengths:

      • Multi-mode fiber: 850nm and 1300nm.

      • Single-mode fiber: Up to 1550nm (1 nanometer = one billionth of a meter).

  • Importance of matching antennas to corresponding wavelengths for optimal signal transmission.