Topic - What is a Network?

What is a Network?
1. What is a Network?
A network connects two or more devices so they can share data and resources (files, printers, internet).
Types
LAN (Local Area Network): Home, office, school
MAN (Metropolitan Area Network): City-wide
WAN (Wide Area Network): Internet, large corporate networks

2. Switch
A switch connects devices inside a LAN and forwards data based on MAC addresses.
Types
Unmanaged: Plug-and-play, no configuration
Managed: Full control (VLANs, STP, security)
Smart: Limited management

3 Switch: Can also route (acts like a router)

3. Router
A router connects different networks and forwards packets based on IP addresses.
Routing Types
Static Routing: Manual routes
Dynamic Routing: Automatic (RIP, OSPF, EIGRP, BGP)
Default Route: “Gateway of last resort”

4. VLAN (Virtual LAN)
A VLAN logically separates a switch into multiple virtual networks.
Types
Default VLAN
Data VLAN
Voice VLAN
Native VLAN
✅ Improves security, performance, and management

5. Trunking
Trunking allows multiple VLANs to travel over a single physical link between switches or switch–router.
Types
802.1Q (Dot1Q): Industry standard ✅
ISL: Cisco proprietary (obsolete)

6. EtherChannel
EtherChannel bundles multiple physical links into one logical link.
Benefits
Higher bandwidth
Redundancy
STP sees it as one link
Types
PAgP (Cisco)
LACP (Standard)
Static (Manual)

7. STP (Spanning Tree Protocol)
STP prevents network loops by blocking redundant paths.
Types
STP
RSTP (Rapid STP) (the image incorrectly says “NSTP”)

8. ACL (Access Control List
An ACL filters network traffic based on rules.
Types
Standard ACL: Source IP only
Extended ACL: Source, destination, protocol, port
Named ACL: ACLs with names instead of numbers

Security takeaway:
Understanding how traffic flows, segments, and gets filtered is critical for firewall rules, IDS/IPS tuning, Zero Trust, and incident response.
You can’t defend what you don’t understand.

#Networking #CyberSecurity #NetworkSecurity #CCNA #SOC #Infosec #SecurityFundamentals

Subsection: IT Knowledge
Section: Student Zone

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