%%{init: {'theme': 'base', 'themeVariables': { 'primaryColor': '#2C3E50', 'primaryTextColor': '#fff', 'primaryBorderColor': '#16A085', 'lineColor': '#E67E22', 'secondaryColor': '#16A085', 'tertiaryColor': '#E8F6F3', 'fontSize': '12px'}}}%%
timeline
title Ethernet Evolution for IoT
1983 : 10BASE5 : 10 Mbps Thick Coax
1985 : 10BASE2 : 10 Mbps Thin Coax
1990 : 10BASE-T : 10 Mbps Twisted Pair
1995 : 100BASE-T : 100 Mbps Fast Ethernet
1999 : 1000BASE-T : 1 Gbps Gigabit
2003 : PoE (802.3af) : 15.4W per port
2009 : PoE+ (802.3at) : 30W per port
2018 : PoE++ (802.3bt) : 90W per port
797 Wired Network Access: Ethernet for IoT
NoteLearning Objectives
By the end of this section, you will be able to:
- Understand the role of Ethernet (IEEE 802.3) in IoT deployments
- Compare different Ethernet standards (10BASE-T, 100BASE-T, 1000BASE-T)
- Identify appropriate use cases for wired IoT connectivity
- Evaluate advantages and disadvantages of Ethernet for IoT devices
- Understand Power over Ethernet (PoE) benefits for IoT installations
797.1 Prerequisites
Before diving into this chapter, you should be familiar with:
- Network Access and Physical Layer Overview: Understanding the role of physical and network access layers in the OSI model
- Networking Basics: Understanding fundamental networking concepts including protocol layers and data transmission principles
TipFor Beginners: What is Ethernet?
Ethernet is the most common wired networking technology. Think of Ethernet cables as highways for data - they’re fast, reliable, and can carry lots of traffic without interruption.
When you plug your computer into a router with a cable, that’s Ethernet! The cable has 8 wires inside arranged in twisted pairs that carry electrical signals representing your data.
| Term | Simple Explanation |
|---|---|
| Ethernet | Wired connection using twisted-pair cables (like RJ45 “phone jack” connectors) |
| 100BASE-T | Fast Ethernet - 100 Mbps (megabits per second) |
| 1000BASE-T | Gigabit Ethernet - 1000 Mbps (10x faster than 100BASE-T) |
| PoE | Power over Ethernet - delivers both data AND electricity through one cable |
| Cat5e/Cat6 | Cable quality ratings - higher numbers = better performance |
797.2 IEEE 802.3 Ethernet for IoT
IoT devices may be connected via a wired connection. For permanent installations, Ethernet is commonly used. The data rate using Ethernet can range from 10 Mbps to more than 1 Gbps (1000 Mbps).
797.2.1 Common Ethernet Standards
10BASE-T: 10 Mbps, found on small microcontrollers and legacy industrial equipment
100BASE-T: 100 Mbps (Fast Ethernet), common on higher-powered microcontrollers or single-board computers like Raspberry Pi
1000BASE-T: 1000 Mbps (Gigabit Ethernet), used for high-bandwidth applications like IP cameras and industrial gateways
NoteExamples of Ethernet-Connected IoT Devices
- IP Cameras: 4K video transmission. Transmitting 4K quality video over Wi-Fi may create problems due to data speed constraints
- VoIP Devices: Voice over IP communications requiring consistent quality
- Set-top Boxes: Video/audio streaming and storage
- Game Applications and Systems: Low-latency gaming
- Static Industrial Equipment: Manufacturing machinery, process control
- High-Security Sensors: Transmitting via wireless is viewed as high-risk; wired preferred
- High-Reliability Control: Robotics, medical applications requiring deterministic communication
797.2.2 Advantages of Ethernet for IoT
| Advantage | Description |
|---|---|
| High bandwidth | 10 Mbps to 10+ Gbps - supports any IoT data rate |
| High reliability | No radio interference, consistent performance |
| Low latency | Sub-millisecond latency for real-time control |
| Deterministic | Predictable timing (critical for industrial) |
| PoE capability | Single cable for data AND power |
| Security | Physical access required - no wireless eavesdropping |
797.2.3 Disadvantages of Ethernet for IoT
| Disadvantage | Description |
|---|---|
| Physical cabling | Requires cable runs to each device |
| Installation cost | Labor-intensive, especially retrofit |
| Limited mobility | Devices must be stationary |
| Not battery-powered | Requires mains or PoE infrastructure |
| Inflexible | Difficult to relocate devices |
TipMVU: Power over Ethernet (PoE)
Core Concept: PoE delivers DC power (15-90W) alongside data over standard Ethernet cables, eliminating separate power wiring for IoT devices like IP cameras, access points, and sensors.
Why It Matters: A single cable installation reduces deployment cost by 30-50% for devices that would otherwise need both Ethernet and power outlets. PoE switches also enable centralized power management and UPS backup for all connected devices.
Key Takeaway: Use PoE for any fixed IoT device consuming under 30W (cameras, access points, sensors, thin clients). PoE++ (802.3bt) extends this to 90W for devices like PTZ cameras and small displays. Always verify both ends support the same PoE standard.
797.3 Worked Example: Ethernet vs Wi-Fi for 4K Video
NoteWorked Example: Comparing Ethernet and Wi-Fi for Video Surveillance
Scenario: A warehouse needs 50 IP cameras for security. Each camera streams 4K video at 25 Mbps. The warehouse is 200m x 150m with metal shelving causing RF interference.
Given: - 50 cameras, each producing 25 Mbps video stream - Total bandwidth: 50 x 25 Mbps = 1,250 Mbps (1.25 Gbps) - Distance from cameras to switches: 50-80 meters - Environment: Metal shelving, forklifts, variable lighting
Analysis:
Option A: Wi-Fi 5 (802.11ac) - Theoretical: 6.9 Gbps shared - Practical: 1-2 Gbps shared across all devices - 50 cameras competing for airtime - Metal interference causes unpredictable dropouts - Result: Insufficient - video stuttering, dropped frames
Option B: Gigabit Ethernet with PoE+ - Each camera gets dedicated 1 Gbps port - 25 Mbps uses only 2.5% of available bandwidth - No radio interference - PoE+ provides up to 30W power per camera - Result: Optimal - consistent 4K streaming
Cost Comparison (50 cameras):
| Item | Wi-Fi | Ethernet |
|---|---|---|
| Infrastructure | $3,000 (6 APs) | $8,000 (2x 24-port PoE switches) |
| Cabling | $500 (power drops) | $5,000 (Cat6 runs) |
| Power outlets | $2,500 (50 outlets) | $0 (PoE) |
| Total | $6,000 | $13,000 |
| Reliability | Variable | Excellent |
Result: Ethernet costs more upfront but provides guaranteed performance. For mission-critical surveillance, the additional $7,000 is justified by eliminating video loss during incidents.
Key Insight: The text states cameras are Ethernet examples because “Transmitting 4K quality video over Wi-Fi may create problems due to data speed constraints.” Ethernet’s deterministic performance is essential for security applications.
797.4 Worked Example: Industrial Robot Control
NoteWorked Example: Selecting Protocol for Industrial Robots
Scenario: A factory needs to connect 50 industrial robots across a 200m x 150m floor. Robots require telemetry every 100ms with <10ms latency and zero packet loss for safety.
Given: - 50 robots with 100ms update interval - Latency requirement: <10ms - Packet loss: Zero tolerance (safety-critical) - Data per update: 500 bytes - Total bandwidth: 50 x (500 bytes x 8 / 0.1s) = 2 Mbps
Requirements Analysis:
| Requirement | Wi-Fi 6 | LoRaWAN | Zigbee | Ethernet+TSN |
|---|---|---|---|---|
| Latency | 3-200ms | 2500ms | 60ms | 0.069ms |
| Packet Loss | 1-5% | 5-10% | 5-10% | 0% |
| Deterministic | No | No | No | Yes |
| Bandwidth | 9.6 Gbps | 50 kbps | 250 kbps | 1 Gbps |
Analysis:
The text explicitly lists “Robotics, medical applications requiring deterministic communication” as Ethernet examples, citing advantages of “Low latency and jitter” and “Deterministic performance.”
- Wi-Fi: 3.7ms typical but 50-200ms worst-case spikes (non-deterministic). 1-5% packet loss unacceptable for robot safety.
- LoRaWAN: 2,500ms latency is 250x too slow. Transmission time (1.45s) exceeds update interval (100ms).
- Zigbee: 60ms latency > 10ms requirement. 250 kbps cannot support 50 robots reliably.
- Ethernet + TSN: 0.069ms latency with zero jitter. Time-Sensitive Networking guarantees bounded latency.
Result: Gigabit Ethernet with TSN (Time-Sensitive Networking) is the only viable option. TSN extensions (IEEE 802.1Qbv) provide deterministic scheduling, ensuring robot control packets are never delayed.
Key Insight: For safety-critical industrial control, only wired Ethernet can guarantee the bounded latency and zero packet loss required. Wireless protocols are fundamentally non-deterministic due to shared medium access.
ImportantKnowledge Check
797.5 Summary
Ethernet remains the gold standard for wired IoT connectivity, offering unmatched reliability and performance for stationary devices.
TipKey Takeaways
When to Use Ethernet: - High-bandwidth applications (video, large data transfers) - Mission-critical systems requiring deterministic timing - Security-sensitive deployments (no wireless eavesdropping) - Static installations where cabling is feasible - Devices that can benefit from PoE (cameras, access points, sensors)
Ethernet Standards for IoT: | Standard | Speed | Use Case | |———-|——-|———-| | 10BASE-T | 10 Mbps | Legacy equipment, simple sensors | | 100BASE-T | 100 Mbps | Microcontrollers, basic IoT | | 1000BASE-T | 1 Gbps | Cameras, gateways, industrial | | PoE/PoE+ | 15-30W | Cameras, APs, sensors | | PoE++ | 90W | PTZ cameras, displays |
Best Practices: 1. Use PoE whenever possible to simplify installation 2. Plan cable runs during construction (cheaper than retrofit) 3. Use Cat6 or better for future-proofing 4. Consider TSN for industrial control applications 5. Ethernet for backbone, wireless for edge where needed
797.6 What’s Next?
Continue to Wireless Network Access: Wi-Fi for IoT to explore IEEE 802.11 wireless protocols including Wi-Fi 6 and Wi-Fi HaLow designed specifically for IoT applications.