Zephyr Connectivity: IP Networking

Build memory-efficient, cloud-connected applications using Zephyr's modular IP stack and industry-standard IoT protocols.

Core Workflows

1. Protocol Selection

Choose the right protocol (LwM2M, CoAP, MQTT) based on your device's power and management needs.

• Reference: [protocol_selection.md](references/protocol_selection.md)
• Key Tools: CONFIG_COAP, CONFIG_LWM2M, CONFIG_MQTT_LIB.

2. IP Stack Configuration

Tune the networking stack to save Flash and RAM while ensuring reliable communication.

• Reference: [ip_stack_config.md](references/ip_stack_config.md)
• Key Tools: CONFIG_NET_IPV4, CONFIG_NET_BUF_RX_COUNT, DNS resolver.

3. SDK & Module Integration

Integrate external cloud SDKs and libraries as first-class Zephyr modules.

• Reference: [sdk_module_integration.md](references/sdk_module_integration.md)
• Key Tools: west.yml, zephyr/module.yml, name-allowlist.

Quick Start (Kconfig for CoAP)

# Minimal stack for CoAP over UDP
CONFIG_NETWORKING=y
CONFIG_NET_UDP=y
CONFIG_NET_IPV4=y
CONFIG_COAP=y
CONFIG_DNS_RESOLVER=y

Professional Patterns (Cloud Connectivity)

• Extreme Trimming: Disable TCP and IPv6 if not strictly required to reclaim 10KB+ of RAM.
• Manifest Control: Use an allow-list in your west.yml to prevent cloning hundreds of megabytes of unused vendor modules.
• Async DNS: Use the asynchronous DNS resolver to prevent blocking the main application thread during host lookup.

Automation Tools

• [net_config_audit.py](scripts/net_config_audit.py): Audit prj.conf networking flags for protocol/profile consistency.

Examples & Templates

• [prj_minimal_coap.conf](assets/prj_minimal_coap.conf): Starter footprint-trimmed CoAP-over-UDP configuration.

Validation Checklist

• [ ] Device obtains network connectivity and resolves DNS for the configured backend.
• [ ] Selected protocol path (CoAP, MQTT, or LwM2M) completes connect and message exchange.
• [ ] Disabled stack features (for example IPv6 or TCP) are absent from final .config when trimmed.
• [ ] RAM/Flash footprint meets the expected optimization target after stack tuning.

Resources

• [References](references/):
• protocol_selection.md: LwM2M vs CoAP vs MQTT.
• ip_stack_config.md: Optimizing buffers and disabling unused protocols.
• sdk_module_integration.md: West manifest management and SDK modules.
• [Scripts](scripts/):
• net_config_audit.py: Quick audit helper for IP stack Kconfig flags.
• [Assets](assets/):
• prj_minimal_coap.conf: Baseline minimal IP profile template.