Chapter 6- Ethernet-VE2 2

Introduction to Networking

  • Course Code: CT043-3-1

  • Module: Ethernet (Frame)

Cisco Ethernet Switching

  • Understand the importance of Ethernet in networking and its basic operational structure.

Lesson Structure and Topics

Topics and Structure of the Lesson

  • Ethernet Frame: Explain the relationship between Ethernet sublayers and frame fields.

  • Ethernet MAC Address: Describe what an Ethernet MAC address is.

  • MAC Address Table: Explain how a switch builds its MAC address table and how it forwards frames.

  • Switch Speeds and Forwarding Methods: Describe methods of switching and port settings available on Layer 2 switch ports.

Key Terms to Master

  • Ethernet encapsulation

  • Data Link sublayers and MAC sublayers

  • Ethernet Frame Fields and MAC address

  • MAC address and Hexadecimal

  • Unicast, Multicast, and Broadcast MAC address

  • MAC address Table

  • Switching learning and Forwarding

  • Frame Forwarding and cut-through switching

  • Half and Full Duplex

  • Duplex and speed settings

  • Auto-MDIX

  • MAC and IP

  • Address Resolution Protocol (ARP)

  • ARP Broadcast and ARP Spoofing

OSI Model

Overview of the OSI Model Layers

  1. Application: Data (Application Layer)

  2. Presentation: Data Representation and Encryption

  3. Session: Data Interhost Communication

  4. Transport: Segments End-to-End Connections and Reliability

  5. Network: Packets Path Determination and Logical Addressing (IP)

  6. Data Link: Frames, MAC and LLC, Physical Addressing

  7. Physical: Bits, Media, Signal, and Binary Transmission

Ethernet Frames

Ethernet Operations

  • Ethernet Layers: Operates in Data Link Layer and Physical Layer.

  • Standards: Defined in IEEE 802.2 and 802.3 standards.

Data Link Sublayers

Functionality of Ethernet Sublayers

  1. LLC Sublayer (IEEE 802.2)

    • Identifies network layer protocols.

  2. MAC Sublayer (IEEE 802.3, 802.11, 802.15)

    • Responsible for data encapsulation and media access control.

MAC Sublayer Functions

  • Data Encapsulation: Consists of Ethernet frame, Ethernet addressing (source & destination MAC addresses), and error detection (FCS - Frame Check Sequence).

  • Media Access: Different standards over media (copper and fiber) using full-duplex and half-duplex.

    • Wired LAN: Operates in full-duplex, eliminates the need for CSMA/CD.

    • Wireless LAN: Shared half-duplex medium using CSMA/CA.

Ethernet Frame Fields

  • Size Specifications: Minimum frame size is 64 bytes; maximum is 1518 bytes.

    • Frames less than 64 bytes discard as collision fragments.

    • Frames over 1500 bytes signify jumbo/baby giant frames.

Ethernet MAC Address

MAC Address Representation

  • Format: 48-bit value expressed in 12 hexadecimal digits.

  • Example: 00-B0-D0-63-C2-26.

  • Uses ARP to view current MAC address with IPCONFIG /ALL.

Unique MAC Addressing

  • All MAC addresses must be unique within the LAN; obtained using a vendor OUI code.

Types of MAC Addresses

Unicast MAC Address

  • Unique address for single device communication.

Broadcast MAC Address

  • Destination = FF:FF:FF:FF:FF:FF; received by all devices on LAN.

Multicast MAC Address

  • Received by a group of devices; starting MAC address format (IPv4: 01-00-5E; IPv6: 33-33).

MAC Address Table

Switch Fundamentals

  • Layer 2 switch uses MAC addresses for forwarding, not concerned with data payload.

  • MAC address table is initially empty when the switch is powered on.

Switch Learning and Forwarding

  • Examines Source MAC addresses to learn the network topologies and make forwarding decisions.

  • Updates timer entries in the MAC address table by default up to 5 minutes.

Filtering Frames

  • By populating its MAC address table, a switch can filter frames to appropriate ports.

Switch Speeds and Forwarding Methods

Frame Forwarding Methods

  1. Store-and-Forward Switching: Entire frame received, CRC computed, and error-checked before forwarding.

  2. Cut-Through Switching: Forwarding starts as soon as the destination MAC is read; no error-checking.

    • Variants: Fast-forward and Fragment-free switching.

Duplex and Speed Settings

  • Full-Duplex: Concurrent send/receive.

  • Half-Duplex: One sends at a time.

  • Duplex Mismatch: Common performance issue; should synchronize settings.

Auto-MDIX Feature

  • Automatically configures the switch port for the correct crossover straight-through cable type.

MAC and IP Interactions

Same Network Connections

  • Layer 2 MAC addresses deliver frames between NICs on the same network.

Remote Network Connections

  • Uses default gateway MAC address when IP address is outside local network; ARP maps IP to MAC correspondence.

ARP Overview

Functions of ARP

  • Resolves IPv4 addresses to MACs, maintaining an ARP table to facilitate communication.

ARP Table Management

  • Entries expire based on cache timers; can be manually cleared.

ARP Issues

  • Excessive broadcasts and spoofing attacks can affect network performance; mitigation techniques should be employed.

Summary

  • Key Focus Areas:

    • Operation of Ethernet and switches.

    • Importance of ARP in facilitating network communication.


Creating a Plinko game using JavaScript involves designing the game logic and visuals. Here's a simplified outline of how to approach this:

Steps to Create a Plinko Game:

  1. Set Up the HTML Structure:

    • Create a canvas element in your HTML file where the game will be rendered.

    <canvas id="plinkoCanvas" width="500" height="600"></canvas>

  2. Initialize the Game in JavaScript:

    • Set up variables for the canvas, context, and game elements such as pegs, balls, and slots.

    const canvas = document.getElementById('plinkoCanvas');
const ctx = canvas.getContext('2d');
// Game variables
const pegs = []; // To hold peg objects
const balls = []; // To hold ball objects
const slots = []; // To hold score slots

  3. Define Pegs and Slots:

    • Create functions to draw pegs and slots on the canvas. For example:

    function drawPeg(x, y) {
    ctx.beginPath();
    ctx.arc(x, y, 5, 0, Math.PI * 2);
    ctx.fillStyle = '#fff';
    ctx.fill();
    ctx.closePath();
}

  4. Implement the Drop Logic for Balls:

    • Create a function to manage the dropping of balls, which will simulate the falling motion and interaction with pegs. For example:

    function dropBall() {
    let ball = { x: 250, y: 0, speed: 0 };
    balls.push(ball);
}

  5. Update and Draw the Game:

    • Use the requestAnimationFrame to continuously update the canvas and redraw pegs, balls, and slots based on their current states.

    function update() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    // Draw pegs
    for (let peg of pegs) { drawPeg(peg.x, peg.y); }
    // Draw balls
    for (let ball of balls) { /* Update and draw ball */ }
    // Check for collisions with pegs and update ball positions
    requestAnimationFrame(update);
}

  6. Handle Win/Loss Scenarios:

    • Determine where the ball lands in the slots and update scores accordingly.

  7. User Interaction:

    • Implement a way for users to "launch" a ball (e.g., by clicking a button) which triggers the dropBall function.

Additional Tips:

  • Use basic physics for ball movement (gravity, bouncing).

  • Customize styling, colors, and scoring system as per your design requirements.

  • Consider using libraries like p5.js for easier handling of graphics and physics.

This is a basic guideline to get you started. You can expand upon this with more features, such as sounds and animated effects.