3.4.1 Deployment Strategies: The Physics of Placement

• Random Deployment: Nodes are dropped from an aircraft (e.g., forest fire monitoring). Requires mathematical models (Poisson point process) to ensure a connected graph.
• Deterministic Deployment: Manual, planned placement (e.g., factory machines). Optimizes signal strength and minimizes gateways.
• Mobile Deployment: Sensors move autonomously (on drones/robots) to fix "Holes" in the network coverage or track a specific moving phenomenon.

3.4.2 The Technical Lifecycle of Node Discovery

1. Bootstrapping: Hardware self-test and loading initial security keys from ROM.
2. Neighborhood Discovery: Sending "Hello" or "DIS" (DODAG Information Solicitation) packets to find nearby active nodes and establish initial trust.
3. Gateway Discovery: Finding the "Edge Router" or "6LBR" that connects the local mesh to the global Internet.
4. Semantic Registration: The device registers its "Capability" (e.g., "I am an O2 sensor, 10-bit accuracy") with a directory service (like CoRE Resource Directory).

3.4.3 Neighbor Discovery (ND) in IoT (Optimizing RFC 4861)

Standard IPv6 ND relies on heavy multicast. IoT optimized ND:

• Registration Model: Nodes register their IPv6 address with the gateway using "EARO" (Address Registration Option).
• Whiteboard Approach: The gateway maintains a central list of all active nodes to prevent redundant multicasting across the whole mesh.

3.4.4 Coverage vs. Connectivity Metrics (Academic)

• k-Coverage: Every point in the physical area is monitored by at least 'k' sensors (ensuring reliability against sensor failure).
• Connectivity: The mathematical property that every node can reach the root gateway via a multi-hop path.