Introduction to Networks

What's a Network?

A Network is a group of devices that can send data to each other. Nowadays, we have invented transmission methods, such as Wi-Fi and Cables.

• Cabled Networks: devices connected thru a cable, the Ethernet Cable (or RJ45)

• Wireless Networks: devices connected thru radio frequencies, such as Wi-Fi.

Ethernet Standards

Speed	Name	Standard	Formal name	Max Distance
10 Mbps	Ethernet	802.3i	10BASE-T	100m
100 Mbps	Fast Ethernet	802.3u	100BASE-T	100m
1 Gbps	Gigabit Ethernet	802.3ab	1000BASE-T	100m
10 Gbps	10Gbit Ethernet	802.3an	10GBASE-T	100m

Trick to remember the standards: I U AB, AN

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Common type of Devices

Switches

• Catalyst 9200

• Catalyst 3650

Routers

• ISR 1000

• ISR 900

• ISR 4000

Firewalls

• ASA5500-X

• Firepower 2100

Next-Generation firewalls are firewalls that introduce modern functionalities and advanced filtering capabilities. They often include IPS, which is an Intrusion Prevention System.

While a Firewall decides if to block or let traffic pass thru the network, and IPS is responsible for analyzing the traffic and, eventually, blocking the packet.

Before Next-Generation Firewalls, IPS and Firewalls were two separate devices.