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=====================================================================
                         LAN TOPOLOGIES CHEATSHEET
=====================================================================


---------------------------------------------------------------------
                             TABLE OF CONTENTS
---------------------------------------------------------------------
1. Overview of LAN Topologies
2. Topologies Explained
   - Star Topology
   - Bus Topology
   - Ring Topology
3. Networking Devices
   - Switches
   - Routers
4. Subnetting Basics
5. Key Networking Protocols
   - ARP
   - DHCP
6. Comparison of Topologies
7. Conclusion

=====================================================================
1. OVERVIEW OF LAN TOPOLOGIES
=====================================================================
LAN Topology: Refers to the design or structure of a network.
Key topologies: Star, Bus, Ring.

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2. TOPOLOGIES EXPLAINED
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----------------------
  STAR TOPOLOGY
----------------------
- Definition:
  Devices connect to a central hub or switch.
- Advantages:
  * Highly scalable.
  * Easy to add/remove devices.
  * Fault isolation is simpler.
- Disadvantages:
  * Expensive (more cabling, central devices).
  * Central point of failure.

----------------------
  BUS TOPOLOGY
----------------------
- Definition:
  Devices connect via a single backbone cable.
- Advantages:
  * Low cost and easy setup.
- Disadvantages:
  * Bottlenecks due to shared bandwidth.
  * Single point of failure in the backbone.
  * Troubleshooting is challenging.

----------------------
  RING TOPOLOGY
----------------------
- Definition:
  Devices form a closed loop, passing data in one direction.
- Advantages:
  * Low cabling requirements.
  * Less prone to traffic bottlenecks.
- Disadvantages:
  * Break in the ring halts the network.
  * Data travels inefficiently across all devices.

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3. NETWORKING DEVICES
=====================================================================

----------------------
  SWITCH
----------------------
- Definition:
  Connects multiple devices, directing traffic only where needed.
- Key Features:
  * Reduces network congestion.
  * Commonly used in larger networks.

----------------------
  ROUTER
----------------------
- Definition:
  Connects different networks and routes data between them.
- Key Features:
  * Enables internet connectivity.
  * Adds redundancy and alternative paths.

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4. SUBNETTING BASICS
=====================================================================
- Definition:
  Divides a network into smaller sub-networks (subnets).
- Purpose:
  * Organize devices into logical groups.
  * Enhance security and efficiency.
- Key Components:
  * Network Address: Identifies the network (e.g., 192.168.1.0).
  * Host Address: Identifies a device (e.g., 192.168.1.100).
  * Default Gateway: Device connecting to other networks 
                     (e.g., 192.168.1.254).

=====================================================================
5. KEY NETWORKING PROTOCOLS
=====================================================================

----------------------
  ARP (Address Resolution Protocol)
----------------------
- Function: Maps IP addresses to MAC addresses.
- Key Concepts:
  * ARP Request: Broadcast to find a MAC address.
  * ARP Reply: Response with the requested MAC address.

----------------------
  DHCP (Dynamic Host Configuration Protocol)
----------------------
- Function: Assigns IP addresses dynamically.
- Packet Types:
  1. DHCP Discover: Device requests an IP.
  2. DHCP Offer: Server offers an IP.
  3. DHCP Request: Device accepts the offer.
  4. DHCP ACK: Server confirms allocation.

=====================================================================
6. COMPARISON OF TOPOLOGIES
=====================================================================
| TOPOLOGY   | COST      | SCALABILITY | REDUNDANCY | TROUBLESHOOTING |
|------------|-----------|-------------|------------|-----------------|
| STAR       | High      | Excellent   | Medium     | Moderate        |
| BUS        | Low       | Poor        | None       | Difficult       |
| RING       | Medium    | Limited     | None       | Easy            |

=====================================================================
7. CONCLUSION
=====================================================================
LAN topologies define how devices are arranged and interact within a 
network. 
- Star topology dominates modern networks due to scalability.
- Bus and Ring are cost-effective but have significant limitations.
Understanding these topologies, alongside protocols like ARP and DHCP, 
ensures robust and efficient network design.