What is a Network? & What are the Core Components of a Network?

"Collection of devices connected together to communicate and share resources is called a Network." or "The fabric that ties business applications (Web Browsers, FTP, Database Applications, Email, Instant Messengers, Online Gaming, Video conferencing/Streaming etc.,) together is called a Network".

The goal of a network is to establish communications and share resources throughout an organization or over the internet. Let’s take a look at some of the core building blocks (components) that make this communication possible:

• Personal Computers (PCs) and Servers: These devices serve as the endpoints in the network and are responsible for sending and receiving data to and from the network.
• Network Connections: You must have a way to attach a device to the network; this building block includes the network interface card (NIC), cabling and connectors.
• Hubs and Switches: These devices provide points on which all the end systems of a network can attach.
• Routers: Routers connect multiple networks together and find the best way to reach each network.
• WLAN devices: These devices connect wireless devices such as computers, printers, and tablets to the network. Since pretty much every device manufactured today has a wireless NIC, you just need to configure a basic access point (AP) to connect to a traditional wired network.
• Access Points or APs: These devices allow wireless devices to connect to a wired network and extend a collision domain from a switch. An AP can be a simple standalone device, but today they are usually managed by wireless controllers either in house or through the internet.
• WLAN Controllers: These are the devices that network administrators or network operations centers use to manage access points in medium to large to extremely large quantities. The WLAN controller automatically handles the configuration of wireless access points and was typically used only in larger enterprise systems.
• Firewalls & Intrusion Prevention Systems: These devices are network security systems that monitor and control the incoming and outgoing network traffic based on predetermined security rules, and is usually an Intrusion Detection & Protection System (IDS/IPS). Cisco PIX firewall and Cisco Adaptive Security Appliance (ASA) firewall typically establish a barrier between a trusted, secure internal network and the Internet, which is not secure or trusted.

These components can build a network within a local area (LAN) or across a wide area (WAN).

Interpretation of a Network Diagram or Placement of Core Network Components:

The following figures show placement of each of the core network components in a network topology: