Routing & RPL Protocol

Find the right routing, DODAG, mode, lab, or production-review chapter

Routing and RPL module index that directs learners to packet-routing fundamentals, RPL standards, DODAG construction, traffic modes, labs, and production review using evidence-based route choices.

Your guide: Packet Pete

“A packet you can’t trace is a claim you can’t defend — name the address, the route, and the hop that dropped it.”

Start With One Packet Path

A routing module is easiest to enter when you follow one packet from a tiny device toward the service that needs it. The packet may cross a sleepy sensor, a mesh parent, a border router, an IPv6 network, and a cloud endpoint, and each hop needs a reason to forward it.

Use this guide from that path outward. First ask what must move, in which direction, under which link and power limits. Then choose the chapter that helps explain the next-hop evidence, RPL structure, DODAG behavior, lab trace, or production review record.

This page is the route map for the routing and RPL module. Use it to choose the first chapter for the problem in front of you, then use the sidebar for the complete chapter list. The route map keeps the module navigable without trying to duplicate every chapter title.

Learning Objectives

By the end of this index, you should be able to:

• Choose between routing fundamentals, RPL concepts, DODAG behavior, traffic modes, labs, and production-review chapters.
• Explain where RPL fits in an IPv6 low-power and lossy network without treating it as a generic mesh synonym.
• Use RPL standards language consistently: LLN, DODAG, Rank, objective function, routing metric, upward route, downward route, and mode of operation.
• Pick a learning path from evidence: packet-forwarding question, constrained-device question, topology-construction question, or deployment-review question.

Module Route Map

Figure 1: Six-stage route map for the Routing and RPL module: routing fundamentals, routing labs and review, IPv6 and 6LoWPAN, RPL fundamentals, RPL DODAG and routing, and RPL labs and production, each labeled with its chapter count.

Choose A Starting Point

I need routing basics Start with Routing Fundamentals and Routing Overview when the question is how packets find a next hop.

I need forwarding mechanics Use Routing Tables, TTL, and Packet Switching when the problem is lookup, loop prevention, or hop-by-hop movement.

I need IoT routing fit Use Routing in IoT and Routing Connectivity when device constraints, gateway boundaries, or lossy links drive the design.

I need RPL vocabulary Start with RPL Fundamentals and Construction, then use RPL Core Concepts and RPL Introduction.

I need DODAG behavior Use DODAG Construction, DODAG Message Flow, Trickle and DODAG Maintenance, and DODAG Worked Example.

I need mode or deployment decisions Use RPL Routing Modes, Traffic and Design, Network Design Lab, and Production and Review.

Recommended Routes

New to packet routing

1. Routing Fundamentals
2. Routing Overview
3. Routing Basics
4. Routing Tables
5. TTL and Loop Limits
6. Routing Review Fundamentals

Building the RPL model

1. RPL Fundamentals and Construction
2. RPL Core Concepts
3. DODAG Construction
4. DODAG Message Flow
5. RPL Routing Modes
6. Traffic and Design

Reviewing a deployment

1. Routing in IoT
2. Convergence Review
3. RPL Network Design Lab
4. Production Framework
5. Production Scenarios
6. Summary Tools

Standards Anchor

RPL is specified for IPv6 low-power and lossy networks, not for every possible mesh. Keep the standards vocabulary tight while reading the module:

• RPL builds and maintains Destination-Oriented Directed Acyclic Graphs, with Rank used to express relative position toward a DODAG root.
• Routing metrics and constraints are separate from the objective function that interprets them.
• OF0 is the baseline objective function; MRHOF is a common objective function that uses hysteresis while minimizing a metric.
• RPL supports traffic toward a root, away from a root, and between devices inside the LLN, but the design evidence should still state which traffic pattern dominates.

The authoritative source set for these statements is RFC 6550 for RPL, RFC 6551 for LLN routing metrics, RFC 6552 for OF0, and RFC 6719 for MRHOF.

Decision Evidence

Packet evidence

• Destination prefix and next-hop behavior
• TTL or hop-limit behavior
• Route table ownership and update source

LLN evidence

• Device memory, energy, and duty-cycle constraints
• Observed link loss, asymmetry, and churn
• Gateway, root, and maintenance ownership

RPL evidence

• Objective function and metric choice
• DODAG construction and repair behavior
• Mode of operation and dominant traffic pattern

Knowledge Check

Match The Route

Order The Learning Path

Summary

Use this module in three layers. First, learn ordinary packet-routing mechanics. Second, connect those mechanics to constrained IoT links. Third, use RPL chapters to reason about DODAG construction, objective functions, routing modes, and production evidence. The fastest route is the one that matches the decision you need to make.

Concept Relationships

• Networking core provides addressing, packet structure, layered models, and transport assumptions.
• Network topologies explain why physical and logical structure affects route choice and failure behavior.
• 6LoWPAN and constrained IPv6 chapters explain the link-layer environment in which RPL is often used.
• RPL chapters turn those foundations into DODAG construction, Rank, metrics, modes of operation, and deployment review evidence.

What’s Next

If the routing vocabulary is still new, start with Routing Fundamentals. If the routing model is clear and the question is RPL-specific, start with RPL Fundamentals and Construction. If you are reviewing a design, use RPL Network Design Lab and Production and Review after the DODAG and mode chapters.