PHASE 04

Hardware, Transmission Media & Cabling

Physical copper & fiber optics specs, switches vs hubs, Power over Ethernet (PoE), fiber converter transceivers, and perimeter firewalls.

🛠️ Attachment Cabinet Troubleshooting: Fiber Converters & PoE

When network internet drops in an enterprise cabinet, check the Fiber Converter Transceiver lights (Link, TX, RX). If Link/RX LED is dark, the fiber line is disrupted. Also, devices like IP CCTV cameras and ceiling WAPs receive electrical power directly over CAT6 cabling using PoE (Power over Ethernet) switches.

1. Physical Transmission Media (Copper vs. Fiber Optic)

Copper Twisted Pair

UTP & STP Copper Cabling

Twisted pairs reduce electromagnetic interference (EMI) crosstalk.

CAT5e: Up to 1 Gbps at 100 meters (100 MHz bandwidth)
CAT6: Up to 10 Gbps up to 55 meters (250 MHz bandwidth)
CAT7: Fully shielded (S/FTP) up to 600 MHz for server racks
Termination: RJ45 connectors using T568B pinout standard

High Speed Optical

Fiber Optic Cables & Converters

Transmits data pulses of light through ultra-pure glass strands (FDDI). Completely immune to EMI.

Single-Mode (SMF): Laser light source, tiny 9µm core, long distance WAN ISP links (tens of kilometers)
Multi-Mode (MMF): LED light source, 50/62.5µm core, shorter data center inter-rack links
Fiber Converters: Converts optical pulses to electrical RJ45 copper signals; operates in TX (transmit) / RX (receive) pairs

2. Network Devices: Hubs vs. Managed Switches vs. Routers

Layer 1 Legacy

Network Hub

Repeats incoming bits to all ports simultaneously (broadcasting). Creates a single shared collision domain running on half-duplex (10Mbps).

⚠️ Outdated bad hardware—causes severe packet collisions.

Layer 2 Intelligent

Managed Switch

Inspects MAC addresses, maintains a MAC Table, and forwards frames strictly to the destination port in full-duplex mode (1Gbps - 10Gbps).

✓ Supports VLAN partitioning & PoE power delivery.

Layer 3 Perimeter

Enterprise Router

Connects separate distinct IP networks (LAN to WAN ISP link). Reads IP addresses to route packets across optimal paths.

🛡️ Houses ARP table, perimeter defense, NAT & firewall rules.

3. Power over Ethernet (PoE) & Perimeter Security

Power over Ethernet (PoE / IEEE 802.3af/at)

Delivers both DC power and Ethernet data simultaneously over a single CAT5e/6 cable. Eliminates the need for AC electrical outlets near ceiling Access Points, VoIP phones, and CCTV IP security cameras.

Firewalls & Intrusion Prevention (IDS/IPS)

Security appliance positioned at the perimeter of the enterprise network. Inspects packet state, blocks malicious traffic, and detects unauthorized penetration attempts before reaching internal servers.