In-Depth Notes on Wired and Wireless Local Area Networks

Information Sharing
- Facilitates improved decision-making by allowing different users to access the same data simultaneously.
- Reduces data duplication and inconsistency as users can work from a single source of truth, ensuring everyone has the latest information.
Resource Sharing
- Peripherals like printers, scanners, and copiers can be shared among multiple clients, leading to cost savings and reduced equipment needs.
- Centralized storage options allow users to access shared files without needing multiple copies on individual machines.
Software Sharing
- Software licenses can be purchased on a per-seat basis rather than for each individual machine, making it more economical.
- Applications reside on a server which simplifies maintenance and upgrades, allowing for quicker rollouts of updates and patches.
Device Management
- Simplifies software updates and configuration management across all connected devices, ensuring consistency in application versions and settings.
- Network administrators can monitor, control, and configure devices remotely, streamlining system management.

Clients
- Devices (like computers, tablets, and smartphones) that request information from servers, allowing users to access resources available on the network.
Servers
- Powerful machines that provide information or services to clients, handling requests while managing data and resources.
Network Interface Cards (NICs)
- Essential devices that connect computers to the network, equipped with a unique MAC address that identifies them.
- Operate at Layers 1 (Physical layer) and 2 (Data link layer) of the OSI model, facilitating communication on the network and is commonly built into motherboards.
Network Cables
Hubs / Switches / Access Points
Software

Wired NIC: Connects a computer to a wired network via cable, ensuring reliable data transmission.
Wireless NIC: Functions as a radio transmitter for wireless networks, allowing for mobility without physical connections.
Most desktops have wired NICs, while most laptops are equipped with both wired and wireless NICs to enable versatile connectivity.

Commonly use:
- Unshielded Twisted-Pair (UTP): Low cost and widely used for general networking purposes.
- Shielded Twisted-Pair (STP): Provides better protection against electrical interference, making it suitable for environments like factories.
- Fiber-Optic Cable: Offers superior performance with higher data rates and is less susceptible to interference but at a higher cost and installation complexity.

Utilize radio waves for data transmission between NICs and access points (APs), allowing for flexibility in device placement.
Operate mainly in 2.4 GHz and 5 GHz frequency ranges to balance speed and range.
It is crucial to ensure that APs do not interfere with one another; therefore, each AP must use different channels to optimize performance without overlap.

Name	Type	Max Data Rate	Used by
Category 3	UTP	10 Mbps	10BASE-T
Category 5	UTP/STP	100 Mbps	100BASE-T
Category 5e	UTP/STP	1 Gbps	1000BASE-T
Category 6/6a	UTP/STP	10 Gbps	10GBASE-T
OM1 (62.5/125 µm)	Fiber	1-10 Gbps	1000BASE-SX
OM3 (50/125 µm)	Fiber	10-100 Gbps	10GBASE-SR

Hubs: Basic junction points allowing devices to connect; function primarily as signal repeaters without processing data packets.
Switches: Intelligent devices that direct traffic and determine the best path for data to ensure that it reaches only the intended recipient, enhancing overall efficiency.

Use radio waves to connect wireless clients to wired networks, enabling devices without physical connections to communicate effectively.
Can utilize Power over Ethernet (PoE), which simplifies the installation process by reducing the number of cables needed for power and data transmission.

Network Operating System (NOS): Centralizes management functions and operations on both servers and clients, facilitating communication within the network.
Provides directory services about LAN resources via Active Directory Services (ADS), enabling efficient resource navigation and user management.
Enhances collaboration and security within LANs by implementing user authentication, permissions, and data encryption protocols.

Defined by IEEE 802.3 standards; foundational for most LANs today, ensuring devices can communicate effectively over wired connections.
Topology: Refers to the layout of a network, including both logical (conceptual) representations of how data flows) and physical (actual installation and placement of network hardware).
Hub-Based Ethernet: A ethernet network connects all devices through a central hub that broadcasts data to every device, leading to network congestion and collisions. It operates at the Physical Layer (Layer 1) and is inexpensive but inefficient for modern networking.
Switch-Based Ethernet: A ethernet network connects devices through a switch that forwards data only to the intended recipient, reducing traffic congestion and improving speed. It operates at the Data Link Layer (Layer 2) and is widely used for its efficiency, full-duplex communication, and ability to handle high-performance networking.

CSMA/CD (Carrier Sense Multiple Access with Collision Detection): The most common wired access method, enabling multiple devices to share the same communication channel effectively.
Collision Handling: If a collision occurs (two devices transmitting at once), devices wait a random time before retransmitting, significantly reducing the likelihood of a subsequent collision.

Known as Wi-Fi; governed by IEEE 802.11 standards, allowing devices to connect wirelessly, enabling greater mobility and flexibility.
Employs radio frequencies for transmission and features security solutions, including WEP, WPA, and WPA2 to ensure encrypted and secure access.

Best practice: Use wired LANs as the primary networking backbone while incorporating wireless as a supplemental layer due to challenges related to interference with wireless signals.
Conduct comprehensive site surveys to assess coverage, potential sources of interference, existing wired infrastructure, and optimal placements for access points.

Strategies to enhance throughput involve identifying bottlenecks, upgrading devices, segmenting networks, and actively managing network demand to ensure efficiency.
Implement load balancing across servers, upgrade client machines periodically, and optimize server performance for an overall improvement in network productivity.

The commoditization of LAN equipment is driving down costs and improving access to technology.
A notable shift towards wireless technologies, especially in small office/home office (SOHO) environments, is reshaping networking norms.
The influence of the Internet of Things (IoT) poses new challenges and opportunities for future LAN design, requiring adaptability and scalability in network infrastructures.