đź”—

Overview of Inter Networking Devices

May 8, 2025

Cisco Certified Network Associate - Day 4: Inter Networking Devices

Introduction

  • Trainer: Imran Rafai
  • Focus: Inter networking devices for CCNA syllabus
  • Devices discussed: Hub, Switch, Router
  • End with data transmission methods
  • Move towards real-time scenarios and hands-on practice

Hub

  • Characteristics:

    • Non-intelligent device
    • Lacks hardware CAM table or MAC table
  • Functionality:

    • Repeats input data to all ports
    • Only one collision domain
    • One broadcast domain
  • Issues:

    • Cannot segregate communications
    • Poor performance with increased network size due to broadcast traffic

Switch

  • Characteristics:

    • Intelligent device with ASIC
  • Functionality:

    • Stores MAC addresses
    • Learns port connections within ~10 seconds
    • Allows specific destination communication without broadcasting
    • 24-port switch = 24 collision domains
    • One broadcast domain (assuming no VLAN configured)
  • Additional Info:

    • VLANs alter broadcast domain dynamics

Router

  • Characteristics:

    • Intelligent device
  • Functionality:

    • Many collision domains (dependent on number of ports)
    • Many broadcast domains
    • Serves as a network border device, directing traffic to the gateway if necessary
  • Operation:

    • Drops broadcast traffic not relevant to another domain
    • Each interface connects to a different network

Data Transmission

Local Network Transmission

  • Example:

    • Device 10.1.1.10 communicating with 10.1.1.11
  • Addressing:

    • Layer 3 (IP address) and Layer 2 (MAC address)
    • Uses ARP (Address Resolution Protocol) to find MAC addresses
  • Process:

    • Broadcast request via switch
    • Gets MAC address from the destination device
    • Sends data packet to the specific destination using learned MAC addresses

Transmission Across Networks

  • Example:

    • Device 10.1.1.10 communicating with 30.1.1.1
    • Subnet mask /24 (255.255.255.0)
  • Routing:

    • If destination is outside the local network, it forwards to the default gateway (router)
    • Router uses the routing table to determine the next hop
  • Process Impact:

    • Layer 2 addresses are updated at each step
    • Routers determine paths based on routing tables

Conclusion

  • Key devices for CCNA: Hub, Switch, Router
  • Understanding device functionalities and data flow is crucial
  • Encourages questions and further interaction via email or comments

Additional Resources

  • Address questions to [email protected]
  • Engage through comments on YouTube for further clarification