Network devices

Network

A computer network is a digital telecommunications network which allows nodes to share resources. Eg: 2 PCs connected through a cable.

Nodes

• Router

• Switch

• Firewall (hardware)

• Server - device that provides functions or services for clients

• Client - device that accesses a service made available by a server. (together with server - end hosts/points)

Switches

• used to forward traffic within a LAN (provide connectivity to hosts within same LAN)

• have many network interfaces/ports for endhosts to connect to (usually 24+)

• do not provide connectivity between LANs or over the internet

• Cisco - Catalyst

Routers

• are used to provide connectivity between LANs

• used to send data over the internet

• have fewer network interfaces than switches

• Cisco - ISR

Firewalls

• monitor and control network traffic based on configured rules

• can be placed 'inside the network' or 'outside the network'

• 'Next generation firewalls' when they include modern and advanced filtering capabilities (IPS - Intrusion Prevention System)

• Cisco - ASA, Firepower

• Network firewalls - hardware devices that filter traffic between networks

• Host-based firewalls - software applications that filter traffic entering and exiting a host machine, like PC