6.04 Compare and contrast Internet connection types, network types, and their features

Introduction 

In this lesson, you'll learn how different types of networks—whether they’re confined to a single building or spread across cities—enable us to solve problems and keep people connected. Understanding these networks not only helps you troubleshoot issues, but also empowers you to assist others in navigating the digital world more effectively. 

LANs and WANs 

Local Area Networks (LANs) 

A Local Area Network (LAN) is a group of computers and devices connected within a single geographical location, such as a building or campus. The computers are linked by cabling and network switches. LANs are typically within 1 or 2 kilometers (about 1 mile) of each other. The organization using the network usually owns and manages all LAN equipment and cabling. 

Key Features of a LAN: 

  • Covers a small area, like a building or nearby buildings. 

  • Devices are connected through cables and switches. 

  • Typically managed by the organization that owns it. 

Ethernet Standards for LANs 

Most cabled LANs use IEEE 802.3 Ethernet standards, which define how devices communicate over a network.

The standards use a naming convention xBASE-Y, where: 

  • x refers to the speed (data rate), and 

  • Y refers to the cable type. 

  • Common Ethernet Standards: 

    • 100BASE-T: Fast Ethernet over copper twisted pair cabling, with speeds of 100 Mbps. 

    • 1000BASE-T: Gigabit Ethernet over copper twisted pair, operating at 1 Gbps (1000 Mbps). This is the most common standard for LANs today. 

    • 10GBASE-T: Ethernet standard using copper cables at 10 Gbps. 

Data Transmission: Copper vs. Fiber Optic 

  • Copper Cabling: Uses electrical signals to transfer data. 

  • Fiber Optic Cabling: Uses pulses of light to send data, providing higher speeds and longer distance capabilities compared to copper.

Wireless LANs (WLANs) 

A Wireless Local Area Network (WLAN) uses radios and antennas instead of cables to transmit data. Most WLANs are based on the IEEE 802.11 standards, commonly known as Wi-Fi. Wi-Fi is often used alongside Ethernet in the same network, allowing both wired and wireless devices to communicate. 

Key Features of a WLAN: 

  • Wireless communication using radio signals. 

  • Based on the IEEE 802.11 (Wi-Fi) standards. 

  • Complements Ethernet by allowing both wired and wireless segments in a network.

Wide Area Networks (WANs) 

A Wide Area Network (WAN) connects multiple LANs over a broad geographic area, such as across cities, countries, or even continents. The Internet is a prime example of a WAN—a global network that connects many smaller networks. 

Key Features of a WAN: 

  • Covers large distances, linking different locations. 

  • Often relies on Internet Service Providers (ISPs) to provide the infrastructure, like cabling and networking equipment. 

  • Used by companies to connect multiple office locations to their central network. 

WAN Services 

Most organizations lease cabling and services from ISPs to connect their LANs across locations. For example, a company might use a WAN to link its branch offices to the main office.

Metropolitan Area Networks (MANs) 

A Metropolitan Area Network (MAN) covers a larger area than a LAN but is smaller than a WAN. A MAN typically spans an entire city or municipality.

Key Features of a MAN: 

  • Connects multiple networks within the same city or metropolitan area. 

  • Larger than a LAN but not as large as a WAN. 

  • Can be used by businesses with several networks in the same urban area. 

SOHO and Enterprise Networks 

SOHO (Small Office/Home Office) Networks 

A SOHO (Small Office/Home Office) LAN is a network designed for small businesses or home offices. It usually supports a few client devices, printers, and possibly a server. SOHO networks are often simple, relying on a single networking device called a SOHO router to provide LAN and Internet connectivity. This device may also be referred to as a broadband router or Internet router.

Key Features of a SOHO Network: 

  • Simple layout, often using one networking appliance. 

  • Connects client devices (computers, printers) to the Internet. 

  • Uses a SOHO router for LAN and Internet management. 

SOHO Router Functions: 

  • Provides Internet access to connected devices. 

  • Manages network traffic and connects devices on the LAN. 

  • Often includes basic firewall functionality for security. 

Enterprise Networks 

Enterprise networks support larger businesses or institutions. Unlike SOHO networks, enterprise networks use separate, dedicated devices for each function (e.g., routers, switches, and firewalls) to handle more clients and offer greater reliability. 

Key Features of an Enterprise Network: 

  • More complex and modular than SOHO networks. 

  • Uses dedicated appliances for each network function (routing, switching, firewalls, etc.). 

  • Designed to support many users and ensure high reliability. 

Enterprise Network Structure: 

  • Client Devices: Workstations, printers, laptops, and mobile devices connect to the network. 

  • Workgroup Switches: These connect client devices to core switches or distribution switches. 

  • Core/Distribution Switches: These connect different network segments, like workgroups, servers, and other parts of the network. 

  • Routers: Forward data between different network segments and out to the Internet. 

  • Firewalls: Protect the network by filtering incoming and outgoing traffic.

Protected Network Zones 

In an enterprise network, protected screened subnets are used to separate the private LAN from the public Internet. These subnets serve as a border between the internal network and the Internet, and traffic is strictly monitored and filtered. 

Key Functions of Network Border Services: 

  • Provide secure Internet access for employees. 

  • Manage email, remote access, and branch office connections through Virtual Private Networks (VPNs). 

  • Host web services for external clients and customers. 

Datacenters and Storage Area Networks (SANs) 

Roles in a Network: Servers and Clients 

  • Server Computer: Dedicated to running network applications and hosting shared resources (e.g., databases, websites, files). 

  • Client Computer: Used by end users to access these applications and resources to perform tasks. 

Server Rooms and Datacenters 

  • Server Room: A dedicated area within a company’s LAN where servers are housed. 

  • Datacenter: A larger facility designed specifically for hosting and managing server resources. Datacenters are built to ensure high availability and reliability for critical applications. 

Key Features of a Datacenter: 

  • Dedicated Networking: High-speed connections to manage heavy server traffic. 

  • Power: Uninterrupted power supplies (UPS) and backup generators to prevent downtime. 

  • Climate Control: Systems that regulate temperature and humidity to protect hardware. 

  • Physical Access Control: Security measures like biometric scanners or keycard access to control entry. 

Google Data Center, The Dalles, Oregon

For climate control a typical cold aisle with server rack fronts facing each other with a raised floor between that distributes cold air.

Storage Area Networks (SANs) 

A Storage Area Network (SAN) is a specialized network designed to provide fast, flexible access to storage resources for servers in an enterprise LAN or datacenter.

Purpose of a SAN: SANs create a shared storage pool that servers can use, making storage more flexible and easier to manage than using local disks on each server. 

  • How SANs Operate: A SAN is separate from the main network, meaning client devices (like PCs and laptops) do not access it directly. Only servers, such as those running databases or applications, connect to the SAN. 

  • Connectivity Technologies: 

    • Fiber Channel: A high-speed network technology used to connect servers to storage devices within a SAN. 

    • Internet SCSI (iSCSI): Allows servers to access SAN storage over IP-based networks.

Fibre Channel SAN connects servers to storage by way of Fibre Channel switches.

In a modern enterprise, SANs help improve storage management, scalability, and reliability by centralizing storage in a way that multiple servers can use. 

Personal Area Networks (PANs) 

A Personal Area Network (PAN) is a wireless network that connects devices over short distances, typically a few meters. It allows various devices to communicate and share data in a personal, localized space. 

Common Uses of PANs: 

  • Data Sharing: Connecting a PC to mobile devices or wearable tech like smartwatches for data transfer. 

  • Connecting Peripherals: Linking devices such as: 

    • Printers 

    • Headsets 

    • Speakers 

    • Video Displays 

This cell phone connected to a laptop allows them to communicate with each other, is an example of a personal area network (PAN)

Growth of PANs: 

With the rise of the Internet of Things (IoT), where everyday objects like home appliances and clothing become interconnected, the use of PANs is expanding. This growth is driven by the increasing number of devices that need to communicate with one another wirelessly. 

Summary 

You've made fantastic progress in understanding network types and their functions! From local and wide area networks (LANs and WANs) to smaller setups like SOHO networks and personal area networks (PANs), you're now familiar with key components that keep devices connected. You've also explored how data centers, storage area networks (SANs), and enterprise systems are designed to handle large-scale data processing and storage. Your grasp of these networking concepts puts you in a strong position to understand how modern organizations maintain efficient, secure, and scalable networks! Keep it up!