Cheatsheet: Networking Hardware

1. Cable Types and Connectors

1.1 Twisted Pair Cables

1.2 Ethernet Cable Categories

1.3 Twisted Pair Connectors

1.4 Cable Wiring Standards

1.5 Fiber Optic Cables

1.6 Fiber Optic Connectors

1.7 Coaxial Cable

1.8 Coaxial Connectors

1.9 Plenum vs Non-Plenum

2. Network Devices

2.1 Hub

• Layer 1 (Physical) device
• Broadcasts incoming data to all ports
• Creates single collision domain
• Half-duplex communication
• Obsolete technology

2.2 Switch

• Layer 2 (Data Link) device; some Layer 3 capable (managed switches)
• Forwards frames based on MAC address table
• Each port is separate collision domain
• Full-duplex communication
• Learns MAC addresses dynamically
• PoE (Power over Ethernet) capable models available

2.2.1 Switch Types

2.3 Router

• Layer 3 (Network) device
• Routes packets between different networks/subnets
• Uses IP addresses and routing tables
• Separates broadcast domains
• NAT (Network Address Translation) capable
• Firewall features in SOHO models

2.4 Access Point (WAP)

• Provides wireless network connectivity
• Connects to wired switch via Ethernet
• Can support multiple SSIDs
• PoE powered in many deployments
• Autonomous or controller-based management

2.5 Wireless LAN Controller

• Centralized management of multiple access points
• Configuration, security, and monitoring
• Roaming support across APs
• Enterprise wireless deployments

2.6 Modem

2.7 Firewall

• Controls traffic based on security rules
• Stateful inspection of packets
• Port filtering and application control
• Network-based or host-based
• DMZ configuration support

2.8 Patch Panel

• Centralized cable termination point
• Mounted in rack; connects wall jacks to switches
• 110 or Krone punch-down blocks
• Organized cable management
• Facilitates easy reconfiguration

2.9 PoE Devices

• Injector: adds power to non-PoE switch port
• Splitter: separates power from data for non-PoE devices

2.10 Network Attached Storage (NAS)

• Dedicated file storage device on network
• Accessible via SMB/CIFS, NFS, AFP
• RAID support for redundancy
• Web-based management interface

2.11 Load Balancer

• Distributes traffic across multiple servers
• Improves availability and performance
• Health checking and failover
• Round-robin, least-connections, IP hash algorithms

2.12 Proxy Server

• Intermediary between clients and internet
• Content filtering and caching
• Hides internal IP addresses
• Access control and logging

3. Network Tools and Equipment

3.1 Cable Crimper

• Attaches RJ45 or RJ11 connectors to cables
• Crimps connector pins into wire conductors
• Required for custom cable lengths

3.2 Cable Stripper

• Removes outer jacket from cable
• Adjustable for different cable gauges
• Prevents damage to inner conductors

3.3 Punch-Down Tool

• 110 and Krone blade types
• Terminates wires into patch panels and keystone jacks
• Cuts excess wire during termination

3.4 Wire Snips/Cutters

• Flush-cut for clean wire ends
• Trims conductors before crimping

3.5 Cable Tester

• Verifies cable continuity and wiring order
• Detects opens, shorts, miswires, split pairs
• LED indicators for each wire pair
• Basic connectivity testing

3.6 Tone Generator and Probe

• Tone generator: sends signal down cable
• Probe (toner): detects signal audibly
• Traces cables in walls, patch panels, bundles
• Identifies unlabeled cables

3.7 Loopback Plug

• Tests network port functionality
• Redirects transmit to receive pins
• RJ45 or fiber versions
• Diagnostic testing tool

3.8 Network Tap

• Copies network traffic for monitoring
• Passive device; no packet modification
• Security monitoring and troubleshooting

3.9 Fusion Splicer

• Permanently joins fiber optic cables
• Uses electric arc to melt and fuse fibers
• Precision alignment required
• Low signal loss connection

3.10 Optical Time Domain Reflectometer (OTDR)

• Tests fiber optic cable integrity
• Measures length, attenuation, breaks
• Locates faults and splice points
• Sends light pulse and analyzes reflections

3.11 Light Meter/Power Meter

• Measures optical signal strength (dBm)
• Verifies acceptable fiber signal levels
• Used with light source for loss testing

3.12 Multimeter

• Measures voltage, current, resistance
• Tests PoE voltage on network cables
• Verifies power supply outputs

3.13 Cable Certifier

• Advanced cable testing beyond basic testers
• Certifies cable meets Cat 5e/6/6a specifications
• Measures attenuation, NEXT, return loss, delay skew
• Generates certification reports
• Validates installation compliance

3.14 Spectrum Analyzer

• Analyzes wireless frequencies and interference
• Identifies channel congestion and noise sources
• Optimizes wireless network placement
• Detects rogue access points

4. Ethernet Standards

4.1 Common Ethernet Standards

4.2 PoE Standards Reference

• Uses pins 1, 2, 3, 6 (data pairs) or 4, 5, 7, 8 (spare pairs)
• Mode A: power on data pairs
• Mode B: power on spare pairs
• Backward compatible (PoE+ devices work with PoE)

5. Connector Pin-Outs and Wiring

5.1 T568A Pin-Out

1. White/Green
2. Green
3. White/Orange
4. Blue
5. White/Blue
6. Orange
7. White/Brown
8. Brown

5.2 T568B Pin-Out

1. White/Orange
2. Orange
3. White/Green
4. Blue
5. White/Blue
6. Green
7. White/Brown
8. Brown

5.3 Active Pins for Ethernet

• 10/100Base-T: pins 1, 2, 3, 6 (2 pairs)
• 1000Base-T: pins 1, 2, 3, 4, 5, 6, 7, 8 (all 4 pairs)
• Transmit on pins 1, 2; receive on pins 3, 6 (10/100)

6. Installation and Deployment Considerations

6.1 Cable Distance Limitations

• Twisted pair: 100m max (90m horizontal + 10m patch cables)
• Multi-mode fiber: 220m-2km (depends on standard and wavelength)
• Single-mode fiber: 10-40+ km (depends on standard)
• Exceeding distance causes signal degradation and packet loss

6.2 EMI/RFI Considerations

• Keep cables away from fluorescent lights, motors, power lines
• Minimum 12 inches from electrical conduit
• Use STP or fiber in high-interference environments
• Avoid parallel runs with power cables

6.3 Cable Management Best Practices

• Label all cables at both ends
• Use cable trays and raceways
• Avoid tight bends (4x cable diameter minimum bend radius)
• Do not exceed 25 lbs pull tension for Cat 6
• No kinks or crushing of cables
• Maintain twist rate up to termination point

6.4 Fiber Optic Handling

• Clean connectors before mating (alcohol wipes, lint-free)
• Never look into fiber ends
• Use dust caps when disconnected
• Minimum bend radius: 10x cable diameter
• Inspect for cracks and scratches

6.5 Rack Installation

• Standard 19-inch equipment racks
• 1U = 1.75 inches height
• Bottom-to-top: UPS, patch panel, switches, servers, cable management
• Leave space for airflow and cooling