1. NETWORKING DEVICES

What is a network?

A computer network is a digital telecommunications network allows NODES to share RESOURCES.

A CLIENT is a device that accesses a service made available by a SERVER.

A SERVER is a device that provides functions or services for CLIENTS.

• Note : The same device can be a CLIENT in some situations and a SERVER in other situations. Ex: A Peer-to-Peer network.

SWITCHES (Level 2):

• provide connectivity to hosts within the same LAN (Local Area Network)
• Have many network interfaces/ports for End Hosts to connect to.
• DO NOT provide connectivity between LANs/over the Internet.

ROUTERS (Level 3):

• have fewer network interfaces than switches.
• are used to provide connectivity BETWEEN LANs.
• are used to send data over the Internet.

FIREWALL (Can be Level 3,4, and 7):

• Firewalls are specialty hardware network security devices that control network traffic entering/exiting your network.
• Can be places "inside" or "outside" the network.
• Monitor and control network traffic based on configured rules.
• Are known as "Next-Generation Firewalls" when they include more modern and advanced filtering capabilities.
• Host-based firewalls are software applications that filter traffic entering and exiting a host machine, like a PC.