Network Communication Protocols

• Protocols are vital for computer communication across networks.
• Ensure correct message formatting, sizing, timing, encoding, encapsulation, and patterning.
• Protocols establish a common language for devices, enabling interoperability and effective data exchange.
• Without protocols, devices cannot understand each other, leading to communication failures.
• Common protocols: HTTP, TCP, IP, and Ethernet, each plays specific roles in network communication.
• Protocol stack visualizes the layered approach to networking.

Key Components of Protocols

• Message Format: Specifies the structure of messages for receiver understanding.
• Message Size: Defines the maximum size of data packets, which varies.
• Timing: Governs data transmission speed and device timing, impacting network efficiency.
• Encoding: Converts messages into bits, then into transmittable signals (electrical, optical, or radio).
• Encapsulation: Adds headers with addressing info for proper routing.

Message Patterns and Acknowledgments

• Reliable communication protocols require acknowledgment of receipt before the next message (TCP).
• Others stream data without acknowledgment for efficiency (video streaming).
• Understanding patterns is crucial for robust network applications to handle various scenarios.

Definition and Role of Standards

• Standards: Formalized rules dictating networking protocol implementation, ensuring consistency.
• Facilitate communication between different devices and enable interoperability.
• Internet standards: Developed through discussion, problem-solving, and testing, often documented in RFCs (Request for Comments).
• The IETF (Internet Engineering Task Force) is a key organization in the development and maintenance of these standards.

The RFC Process

• Each proposed standard undergoes a rigorous development and approval process, tracked through numbered RFC documents.
• RFCs document the evolution of standards, providing transparency and historical context.

Understanding Protocol Stacks

• Protocol stack: Layered representation of networking protocols, each layer having a specific function.
• The TCP/IP model: Application, Transport, Internet, and Network Access layers.
• Each layer operates independently, allowing for modular design and easier troubleshooting.

The OSI Model

• OSI (Open Systems Interconnection) model: Seven layers of network communication.
• Application Layer: Interfaces with user applications, provides data representation and dialog control.
• Presentation Layer: Ensures data is in a usable format, handles encryption and compression.
• Session Layer: Manages sessions and controls dialogues between applications.
• Transport Layer: Responsible for reliable data transfer and segmentation.
• Network Layer: Handles routing and forwarding of packets across the network.
• Data Link Layer: Manages node-to-node data transfer and error detection.
• Physical Layer: Defines the physical means of transmitting data over the network.

Types of Network Media

• Modern networks use metal wires, fiber-optic cables, and wireless transmission.
• Metal Wires: Traditional copper cables, transmitting data as electrical impulses.
• Fiber-Optic Cables: Use light pulses, offering high speed and resistance to interference.
• Wireless Transmission: Employs electromagnetic waves.

Criteria for Choosing Media

• Factors to consider: maximum distance, environmental conditions, data volume/speed, and cost.
• Maximum distance the media can effectively transmit signals.
• Environmental conditions where the media will be installed (e.g., indoor vs. outdoor).
• Data volume and transmission speed requirements.
• Cost of installation and maintenance of the media.

Ethernet Protocol Standards

• Ethernet standards: Define frame format, size, timing, and encoding.
• Ethernet frames contain source/ destination MAC addresses.
• Encapsulation: Wrapping data in frames for transmission.

Access Layer Functionality

• Access layer connects end devices, providing the first point of contact.
• Ethernet hubs and switches are key devices.
• Switches offer improved performance by reducing collisions through MAC address tables.
• Switches dynamically learn and update MAC addresses, optimizing data flow.