Preamble:
This space will be utilized to synthesize my notes and help improve my learning process while I study for the CompTIA Network+ N10-009 certification exam. Please follow along for more Network+ notes and feel free to ask any questions or, if I get something wrong, offer suggestions to correct any mistakes.

A network can be as simple as two computer systems linked by transmission media like cables or radio waves that share protocols (rules) for exchanging data. A computer in this setup is called a "node," and nodes are connected by links. Nodes can send, receive, and forward data (traffic), while links are the pathways that enable communication between them. Nodes can be categorized into two types: Intermediate Nodes and End Systems. Intermediate Nodes handle forwarding functions, helping move traffic to its intended destination. End System Nodes are devices that send or receive data, and they are commonly known as Hosts.

Client-Server vs. Peer-to-Peer Networks

End System nodes are classified as either Clients or Servers. Servers provide services to other hosts on the network—for example, a File Server that shares files or a Print Server that manages print jobs. Clients request and use these services, such as accessing files from a File Server or sending print jobs to a Print Server.

There are generally two types of network topologies: Client-Server and Peer-to-Peer.

Client-Server: In this network type, devices like desktops, laptops, and tablets act as clients. These clients connect to more powerful computers called servers that provide various services. All resources are centrally provided, managed, and secured.

Peer-to-Peer: In this network type, each host functions as both a client and a server. This decentralized model distributes management, provisioning, security, and data throughout the network. A typical example of peer-to-peer networking is a small office setup: Host1 stores files needed by Host2. Host2 can access a shared folder on Host1 to work on these files. When finished, Host2 can print the work using a printer connected to Host3. Peer-to-Peer networks can also be referred to as Workgroups.

Enterprise/Business’ typically implement a Client-Server model while home networks generally use Peer-to-Peer.

Appliances, Applications, and Functions

Networks can have Appliances, Applications and functions to help with computing.

Appliances: A network appliance is a computer with an operating system and software designed to perform a specific network task or role. Examples include switches, routers, wireless access points, firewalls, load balancers, and proxies. An appliance can be either a physical hardware device with its own CPU, RAM, and storage, or a virtual appliance running on a hypervisor on a host device like a server or desktop computer. A single hypervisor can support multiple virtual appliances simultaneously, depending on its hardware specifications.

Applications:

Applications are software programs that run network services. These services enable nodes to perform useful tasks like sharing files, sending emails, or printing documents.

Functions:

Networks can be configured with additional properties to perform specific functions. For example, a virtual private network (VPN) allows secure connections to a local network from across the internet. Quality of service (QOS) functions optimize network traffic by prioritizing certain types, such as Voice Over IP (VOIP) or video streaming.

Network Types

Network types are categorized by their size and scope. Size refers to the number of nodes, while scope describes the geographical area where nodes share network space.

Local Area Networks (LAN):

A LAN operates within a single geographical location, where nodes connect directly through cables or short-range wireless technologies (WiFi). Typically, a single organization or user owns and manages the networking equipment. Examples of LANs include:

1. Home network: A simple setup with an all-in-one router/wireless access point connected to your laptop.
2. Small office/home office (SOHO): A business network with a centralized server, client devices, and printers, usually operating through a single internet router.
3. Small and medium-sized enterprise (SME): A network supporting dozens of users, utilizing structured cabling and multiple switches and routers to manage traffic.
4. Enterprise LAN: A large-scale network supporting hundreds or thousands of servers and clients, requiring enterprise-grade switches and routers.
5. Datacenter: A specialized network hosting only servers and storage, without end-user client devices.

Wide Area Network (WAN):

A WAN functions as a "network of networks" connected by long-distance links. In business settings, this could connect a central office with branch offices. WANs can link multiple LANs or enable remote workers to access an Enterprise LAN via the Internet. They typically operate using leased network devices and links managed by service providers.

Network Topology:

Network topology describes the physical or logical structure of a network in terms of nodes and links.

A physical topology describes how nodes are connected by transmission media. For example, nodes may be connected directly via a single cable, or they may connect to a network switch using separate cables for each node.

A logical topology describes how data flows through a network. Using the previous examples, the logical topology remains the same regardless of how devices are physically connected—what matters is that nodes can communicate with each other.

The simplest topology is the point-to-point link, where two nodes connect via a single link. A point-to-point link can be physical or logical. For example, on a WAN, two router appliances might be physically linked through multiple intermediate networks and devices but still share a logical point-to-point link, where each addresses only the other router. In either case, the 1:1 relationship defines a point-to-point link.

Star Topology

In a star topology, each endpoint node connects to a central appliance like a switch or router. This central node mediates all communications between endpoints. Star topologies are the most widely used physical topology today. A similar design—the hub and spoke topology—looks similar but serves a different context. While star topologies are common in LANs, hub and spoke designs are typically used in WANs.

Mesh Topology

Mesh topologies are commonly used in WANs, especially with public networks like the internet. A full mesh network requires each node to have a point-to-point link with every other node. While this provides maximum redundancy, it becomes impractical as networks grow. The number of links required for a full mesh topology can be calculated using:

n(n–1)/2

N is the number of nodes

Due to this exponential growth in connections, networks often use a hybrid mesh approach instead, where only the most important devices have fault-tolerant links.

Thanks for joining me with the start of my networking learning process. I hope you were able to learn something new about computer networking! Make sure to subscribe here for my next set of notes which will be around the OSI model concepts.