donian 1 network

Layer 1 - Physical

Hardware, cabling, and bit transmission.

Layer 2 - Data Link

MAC addresses and switches.

Layer 3 - Network

IP addresses and routers.

Layer 4 - Transport

End-to-end communication via TCP and UDP.

Layer 5 - Session

Manages and terminates communication sessions.

Layer 6 - Presentation

Data encryption, compression, and formatting.

Layer 7 - Application

The layer closest to the user (HTTP, FTP, SMTP).

Port 20/21

FTP (File Transfer Protocol).

Port 22

SSH and SFTP (Secure Shell/Secure File Transfer).

Port 23

Telnet (Unsecure remote access).

Port 53

DNS (Domain Name System).

Port 67/68

DHCP (Dynamic Host Configuration).

Port 80/443

HTTP/HTTPS (Web traffic).

Port 161/162

SNMP (Network Management/Traps).

Port 3389

RDP (Remote Desktop).

Single-mode Fiber

High-speed, long-distance laser transmission.

Multimode Fiber

LED-based, shorter distances (up to 2km).

Plenum Cable

Fire-rated jacket for air-handling spaces.

CIDR

Classless Inter-Domain Routing (e.g., /24).

APIPA

Self-assigned address (169.254.x.x) when DHCP fails.