1039  Z-Wave Source Routing and Network Healing

1039.1 When to Heal Your Z-Wave Network

Required After: - Adding new mains-powered devices (routing slaves) - Moving mains-powered devices - Removing devices from network - Persistent communication failures

Best Practices: - Schedule: Nightly healing during low-use hours (3-4 AM) - After Changes: Heal after adding/moving routers - Symptom: If devices become unreachable, heal network - Frequency: At least monthly for large networks

Healing Time: - Small network (< 30 devices): 5-10 minutes - Medium network (30-100 devices): 15-30 minutes - Large network (100-232 devices): 30-60 minutes

1039.2 Z-Wave Security

Z-Wave has evolved through multiple security frameworks:

1039.2.1 Security Generations

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graph LR
    A[Z-Wave Security Evolution] --> B[No Security<br/>Legacy Devices]
    A --> C[S0 Security<br/>2003-2016]
    A --> D[S2 Security<br/>2017+]

    B --> B1[No Encryption<br/>No Authentication]

    C --> C1[AES-128 Encryption<br/>Weak Key Exchange]
    C --> C2[Single Security Level<br/>Basic Protection]

    D --> D1[S2 Unauthenticated<br/>Basic Devices]
    D --> D2[S2 Authenticated<br/>Standard Devices]
    D --> D3[S2 Access Control<br/>Locks & Alarms]

    D1 --> E1[ECDH Key Exchange<br/>No User Verification]
    D2 --> E2[ECDH + DSK PIN<br/>QR Code Pairing]
    D3 --> E3[ECDH + DSK PIN<br/>Highest Security]

    style A fill:#E67E22,stroke:#2C3E50,color:#fff
    style B fill:#7F8C8D,stroke:#2C3E50,color:#fff
    style C fill:#c0392b,stroke:#2C3E50,color:#fff
    style D fill:#27ae60,stroke:#2C3E50,color:#fff

Figure 1039.1: Z-Wave Security Evolution: Legacy, S0, and S2 Framework Comparison

{fig-alt=“Z-Wave security evolution timeline showing progression from no security in legacy devices through S0 security (2003-2016) with weak key exchange, to modern S2 security (2017+) with three levels: unauthenticated (basic), authenticated (standard with DSK PIN), and access control (highest security for locks and alarms)”}

1039.2.2 Security Framework Comparison

Feature	No Security	S0 Security	S2 Unauthenticated	S2 Authenticated	S2 Access Control
Encryption	❌ None	⚠️ AES-128	✅ AES-128	✅ AES-128	✅ AES-128
Authentication	❌ No	⚠️ Weak	⚠️ None	✅ DSK	✅ DSK + PIN
Key Exchange	N/A	Insecure	ECDH	ECDH	ECDH
Replay Protection	❌ No	⚠️ Basic	✅ Nonce	✅ Nonce	✅ Nonce
Key Verification	N/A	❌ No	❌ No	✅ Yes	✅ Yes
Use Case	Legacy	Legacy	Basic devices	Smart home	Locks, alarms
Overhead	0%	~30%	~15%	~15%	~15%
Battery Impact	Lowest	High	Medium	Medium	Medium

1039.2.3 S2 Security (Recommended)

S2 Security (introduced 2017) provides bank-level security for Z-Wave:

NoteQuiz 4: Z-Wave Security

Question 6: A Z-Wave smart lock uses Z-Wave Security 2 (S2) with the “Authenticated” security class. What cryptographic key exchange mechanism is used during device inclusion (pairing)?

💡 Explanation: Z-Wave Security 2 (S2) uses Elliptic Curve Diffie-Hellman (ECDH) for key exchange, with a user-entered 5-digit DSA (Device Specific Authentication) PIN to prevent man-in-the-middle attacks during inclusion. During pairing, the controller and device exchange public keys over-the-air, and the user enters the PIN from the device’s QR code or manual. This authenticates both parties and derives a unique encryption key. S2 is significantly more secure than legacy S0 (which had a known zero-key vulnerability) and provides AES-128-CCM encryption for all subsequent communications.

1039.3 S2 Security Features

1. Three Security Levels: - S2 Access Control: Highest security for locks, garage doors, alarms - S2 Authenticated: Standard security for lights, sensors, switches - S2 Unauthenticated: Basic security for low-value devices

2. Key Features: - ECDH Key Exchange: Elliptic curve Diffie-Hellman for secure key exchange - DSK (Device Specific Key): Unique key per device, usually QR code or printed on device - Nonce-Based: Replay attack protection - Forward Secrecy: Compromised message doesn’t compromise future messages

3. Inclusion Process (S2 Authenticated): 1. User scans DSK (QR code or manually enters first 5 digits) 2. Key Exchange: Device and controller exchange keys using ECDH 3. Verification: User confirms DSK matches (prevents man-in-the-middle) 4. Network Key: Device receives encrypted network key 5. Secure Communication: All future messages encrypted

4. Benefits: - Reduced Overhead: ~15% vs ~30% (S0) - Better Battery Life: Less encryption overhead - Stronger Security: Modern cryptography - User-Friendly: QR code scanning simplifies inclusion

1039.4 Z-Wave Plus and Z-Wave Long Range

1039.4.1 Z-Wave Plus (2013, updated 2020)

Z-Wave Plus is a certification program with enhanced features:

Key Improvements: - Better Range: ~30% longer range than Classic - More Battery Life: ~50% improvement - Better RF Performance: 500-series and 700-series chips - Self-Healing: Improved automatic route optimization - Over-The-Air Updates: Firmware updates via Z-Wave - Beaming: Wake battery devices for incoming commands - Network Wide Inclusion: Add devices from anywhere in network - S2 Security: Mandatory in Plus v2

1039.4.2 Z-Wave Long Range (2020)

Z-Wave LR extends range dramatically:

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graph TB
    A[Z-Wave Long Range<br/>700 Series] --> B[Range Extension]
    A --> C[Topology Change]
    A --> D[Use Cases]

    B --> B1[Up to 1 km<br/>vs 100m Classic]
    B --> B2[Sub-GHz Frequencies<br/>Better Penetration]

    C --> C1[Star Topology<br/>Direct to Controller]
    C --> C2[No Mesh Hops<br/>Single-Hop Only]
    C --> C3[Coexists with Classic<br/>Dual-Mode Devices]

    D --> D1[Large Properties<br/>Farms, Estates]
    D --> D2[Outdoor Sensors<br/>Perimeter Security]
    D --> D3[Agriculture<br/>Soil Sensors]

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    style B fill:#16A085,stroke:#2C3E50,color:#fff
    style C fill:#2C3E50,stroke:#16A085,color:#fff
    style D fill:#7F8C8D,stroke:#2C3E50,color:#fff

Figure 1039.2: Z-Wave Long Range (LR): 1km Star Topology for Large Properties

{fig-alt=“Z-Wave Long Range (LR) architecture diagram showing range extension up to 1 km using sub-GHz frequencies, star topology with direct connection to controller instead of mesh, and use cases including large properties, outdoor sensors, and agricultural applications”}

Z-Wave LR Features: - Range: Up to 1 km (vs ~100m for Classic) - Data Rate: 100 kbps (same as Classic) - Topology: Star (no mesh) - Use Case: Large properties, agriculture, industrial - Coexistence: Can run alongside classic Z-Wave

Comparison:

Feature	Z-Wave Classic/Plus	Z-Wave Long Range
Range	30-100m	Up to 1 km
Topology	Mesh	Star (direct to controller)
Routing	Multi-hop	Single-hop only
Battery Life	Years	Years (similar)
Use Case	Home automation	Large areas, agriculture
Devices	232 per network	2000+ per controller

NoteQuiz 5: Z-Wave Plus and Z-Wave Long Range

1039.5 Z-Wave vs Zigbee vs Thread

The three main mesh protocols for home automation:

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graph TB
    A[Home Automation<br/>Mesh Protocols] --> B[Z-Wave]
    A --> C[Zigbee]
    A --> D[Thread]

    B --> B1[Sub-GHz 868/908 MHz<br/>232 Devices Max<br/>Proprietary<br/>Source Routing]

    C --> C1[2.4 GHz<br/>65,000 Devices<br/>Open IEEE 802.15.4<br/>Table Routing]

    D --> D1[2.4 GHz<br/>250 Devices<br/>Open IEEE 802.15.4<br/>Native IPv6]

    B1 --> E1[Best Range<br/>Less Interference<br/>Higher Cost]
    C1 --> E2[Lower Cost<br/>Large Scale<br/>Wi-Fi Interference]
    D1 --> E3[IP Native<br/>Matter Support<br/>Modern Design]

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    style C fill:#16A085,stroke:#2C3E50,color:#fff
    style D fill:#7F8C8D,stroke:#2C3E50,color:#fff

Figure 1039.3: Z-Wave vs Zigbee vs Thread: Home Automation Protocol Comparison

{fig-alt=“Comparison of three home automation mesh protocols: Z-Wave (sub-GHz, proprietary, best range with less interference but higher cost), Zigbee (2.4 GHz open standard with large scale support but Wi-Fi interference), and Thread (2.4 GHz with native IPv6 and Matter support, modern design)”}

Feature	Z-Wave	Zigbee	Thread	Wi-Fi
Frequency	Sub-GHz (868/908 MHz)	2.4 GHz	2.4 GHz	2.4/5 GHz
Max Devices	232	65,000	250	~250
Range (indoor)	30-100m	10-30m	10-30m	50-100m
Data Rate	100 kbps	250 kbps	250 kbps	1-1000 Mbps
Mesh Type	Source routing	Table routing	Table routing	No (standard)
Native IP	❌ No	❌ No	✅ IPv6	✅ Yes
Standard	Proprietary (Silicon Labs)	Open (IEEE 802.15.4)	Open (IEEE 802.15.4)	Open (IEEE 802.11)
Licensing	✅ Required (\[$) | ❌ Not required | ❌ Not required | ❌ Not required | | **Power** | Very Low | Very Low | Very Low | High | | **Security** | S2 (AES-128) | AES-128 | AES-128, DTLS | WPA2/3 | | **Interference** | Low (sub-GHz) | High (2.4 GHz crowded) | High (2.4 GHz) | High (2.4 GHz) | | **Interoperability** | High (certification) | Medium | High (Matter) | Very High | | **Cost per Device** | \]$ (licensing)	$	$	$$

1039.5.1 Strengths and Weaknesses

NoteQuiz 6: Z-Wave vs Zigbee vs Thread

Question 1: Why does Z-Wave use sub-GHz frequencies (868/908 MHz) instead of 2.4 GHz like Zigbee and Wi-Fi?

💡 Explanation: Sub-GHz frequencies (868/908 MHz) provide significant advantages for smart home applications: better range (100-150m outdoor vs 30-75m for 2.4 GHz), superior wall penetration (-3 to -6 dB per wall vs -6 to -12 dB), and much less interference from Wi-Fi, Bluetooth, and microwave ovens that crowd the 2.4 GHz band. Physics (Friis equation) shows 2.4 GHz has +8.4 dB worse path loss than 908 MHz. Lower frequencies can “bend” around obstacles better and penetrate building materials more effectively.

1039.6 Z-Wave Strengths

✅ Longer range (sub-GHz penetrates better) ✅ Less interference (dedicated frequency) ✅ Interoperability (strict certification) ✅ Mature ecosystem (20+ years) ✅ Single vendor (consistency)

❌ Proprietary (licensing fees, vendor lock-in) ❌ Regional frequencies (devices not globally compatible) ❌ Lower device limit (232 vs 65,000 Zigbee) ❌ Higher cost (licensing fees passed to consumer) ❌ No native IP (cannot connect directly to internet)

NoteZigbee Strengths

✅ Open standard (no licensing fees) ✅ Massive scale (65,000 devices) ✅ Lower cost (no licensing) ✅ Global (2.4 GHz worldwide)

❌ Shorter range (2.4 GHz) ❌ 2.4 GHz interference (Wi-Fi, Bluetooth) ❌ Interoperability issues (Zigbee vs Zigbee 3.0, profiles) ❌ No native IP

NoteThread Strengths

✅ Native IPv6 (direct internet connectivity) ✅ Matter ecosystem (Apple, Google, Amazon) ✅ Open standard (no licensing) ✅ Modern design (built for IoT from ground up)

❌ Newer (less mature, smaller ecosystem) ❌ Shorter range (2.4 GHz) ❌ 2.4 GHz interference ❌ Requires border router (gateway to internet)

1039.7 Hands-On Lab: Z-Wave Network Design