1027  Matter Protocol Stack and Data Model

1027.1 Matter Protocol Stack: Layered Architecture and Data Model

15 min | Advanced | P08.C46.U02

NoteLearning Objectives

By the end of this section, you will be able to:

• Understand Matter’s complete layered protocol architecture
• Explain how each layer contributes to interoperability
• Describe the Matter Data Model (nodes, endpoints, clusters, attributes, commands)
• Design endpoint structures for multi-function devices
• Map physical device capabilities to Matter cluster implementations

1027.2 Prerequisites

Before diving into this chapter, you should be familiar with:

• Matter Protocol Overview: Understanding what Matter is and why it was created
• Matter Architecture Overview: Introduction to Matter’s architectural concepts
• Networking Basics: IP addressing and network fundamentals
• IoT Protocols Overview: Context for Matter’s position in the protocol landscape

NoteRelated Chapters

Architecture Deep Dives: - Matter Interactions and Commissioning - How devices communicate - Matter Fabric and Security - Multi-admin and encryption

Device Implementation: - Matter Device Types and Clusters - Complete cluster library - Matter Implementation - SDKs and development

Transport: - Thread Fundamentals and Roles - Thread mesh networking

1027.3 For Beginners: Matter Architecture Simplified

TipUnderstanding Matter’s Building Blocks

Think of a Matter device like a well-organized office building:

• The Building (Node) = The physical device (a smart light, thermostat)
• Floors (Endpoints) = Different functional areas (main light, nightlight)
• Departments (Clusters) = Groups of related capabilities (On/Off, Level Control, Color)
• Employees (Attributes) = Specific pieces of information (current brightness: 80%)
• Actions (Commands) = Things you can ask departments to do (turn on, set brightness to 50%)

When you ask Alexa to “dim the living room light to 50%,” here’s what happens: 1. Alexa identifies the Node (your smart light) 2. Selects the correct Endpoint (main light, not nightlight) 3. Finds the Level Control Cluster 4. Sends a MoveToLevel Command with value 50% 5. The cluster updates its CurrentLevel Attribute to 50% 6. The light physically dims to 50%

1027.4 Matter Protocol Stack

1027.4.1 Complete Architecture Overview

Matter Protocol Stack

Figure 1027.1: The Matter protocol stack provides a complete solution for smart home device interoperability. Built on IPv6, it works seamlessly over Thread mesh networks, Wi-Fi, and Ethernet, enabling devices from different manufacturers to communicate using a common language.

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graph TB
    subgraph App["Application Layer"]
        DM[Data Model<br/>Clusters, Attributes, Commands]
        IM[Interaction Model<br/>Read, Write, Subscribe, Invoke]
    end

    subgraph SecLayer["Security Layer"]
        Sec[Message Layer Security<br/>AES-CCM Encryption]
        CASE[CASE: Certificate-Based Auth]
        PASE[PASE: Passcode-Based Auth]
    end

    subgraph MsgLayer["Message Layer"]
        ML[Message Framing<br/>Headers, Payloads, Acks]
    end

    subgraph TransLayer["Transport Layer"]
        MRP[MRP: Message Reliable Protocol<br/>Retransmission, Deduplication]
        UDP[UDP / TCP]
    end

    subgraph NetLayer["Network Layer"]
        IPv6[IPv6<br/>Addressing, Routing]
    end

    subgraph LinkLayer["Link Layer"]
        Thread[Thread<br/>802.15.4 + 6LoWPAN]
        Wi-Fi[Wi-Fi<br/>802.11]
        Eth[Ethernet<br/>802.3]
    end

    DM --> IM
    IM --> Sec
    Sec --> CASE
    Sec --> PASE
    CASE --> ML
    PASE --> ML
    ML --> MRP
    MRP --> UDP
    UDP --> IPv6
    IPv6 --> Thread
    IPv6 --> Wi-Fi
    IPv6 --> Eth

    style App fill:#16A085,stroke:#2C3E50,color:#fff
    style SecLayer fill:#E67E22,stroke:#2C3E50,color:#fff
    style MsgLayer fill:#2C3E50,stroke:#16A085,color:#fff
    style TransLayer fill:#2C3E50,stroke:#16A085,color:#fff
    style NetLayer fill:#7F8C8D,stroke:#2C3E50,color:#fff
    style LinkLayer fill:#7F8C8D,stroke:#2C3E50,color:#fff

Figure 1027.2: Matter protocol stack showing all layers from application to link layer

{fig-alt=“Matter protocol stack diagram showing six layers: Application Layer (teal) with Data Model and Interaction Model, Security Layer (orange) with AES-CCM and CASE/PASE authentication, Message Layer (navy) for framing, Transport Layer (navy) with MRP and UDP, Network Layer (gray) with IPv6, and Link Layer (gray) with Thread, Wi-Fi, and Ethernet options.”}

NoteAlternative View: Matter Security Architecture

This diagram focuses on Matter’s security mechanisms and trust model.

%% fig-alt: Matter security architecture showing certificate chain, session establishment, and encryption mechanisms
%%{init: {'theme': 'base', 'themeVariables': {'primaryColor': '#2C3E50', 'primaryTextColor': '#fff', 'primaryBorderColor': '#16A085', 'lineColor': '#E67E22'}}}%%
flowchart TB
    subgraph Trust["Trust Model"]
        PAA[Product Attestation<br/>Authority] --> PAI[Product Attestation<br/>Intermediate]
        PAI --> DAC[Device Attestation<br/>Certificate]
    end

    subgraph Session["Session Security"]
        PASE_S[PASE Session<br/>Passcode-based] --> TEMP[Temporary Keys<br/>Commissioning only]
        CASE_S[CASE Session<br/>Certificate-based] --> PERM[Permanent Keys<br/>Normal operation]
    end

    subgraph Msg["Message Protection"]
        MSG[Message] --> ENC[AES-128-CCM<br/>Encryption]
        ENC --> AUTH[Message Auth<br/>Integrity]
        AUTH --> ANTI[Anti-replay<br/>Counters]
    end

    DAC --> CASE_S
    PERM --> MSG

    style Trust fill:#E67E22,color:#fff
    style Session fill:#16A085,color:#fff
    style Msg fill:#2C3E50,color:#fff

1027.4.2 Layer Responsibilities

Layer	Component	Responsibility
Application	Data Model	Define device capabilities (what it can do)
Application	Interaction Model	Define how to access capabilities (how to control it)
Security	CASE/PASE	Establish secure sessions
Security	AES-CCM	Encrypt and authenticate messages
Message	Framing	Structure messages with headers and payloads
Transport	MRP	Ensure reliable delivery over UDP
Network	IPv6	Route packets between nodes
Link	Thread/Wi-Fi/Eth	Physical transmission

1027.4.3 Transport Layer Details

The Message Reliable Protocol (MRP) provides reliable delivery over UDP:

• Acknowledgments: Every message requiring reliability gets an ACK
• Retransmission: Configurable retry intervals (default 200ms initial, exponential backoff)
• Deduplication: Message counters prevent duplicate processing
• Timeout: Sessions expire after configurable idle periods

Why UDP instead of TCP?

Consideration	UDP + MRP	TCP
Latency	Lower (no connection setup)	Higher (3-way handshake)
Power	Lower (simpler stack)	Higher (state maintenance)
Sleepy devices	Better (stateless)	Problematic (connection timeouts)
Multicast	Supported	Not supported

1027.4.4 Link Layer Options

Matter operates over three transport networks:

Transport	Standard	Range	Power	Best For
Thread	802.15.4 + 6LoWPAN	10-30m	Very low	Battery sensors, locks
Wi-Fi	802.11	30-50m	High	Cameras, displays
Ethernet	802.3	Wired	Low	Border routers, hubs

1027.5 The Matter Data Model

1027.5.1 Core Concepts Hierarchy

The Matter Data Model defines how device capabilities are structured and accessed.

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graph TB
    Node[Node<br/>Physical Device] --> EP0[Endpoint 0<br/>Root/Utility]
    Node --> EP1[Endpoint 1<br/>Main Function]
    Node --> EP2[Endpoint 2<br/>Secondary Function]

    EP0 --> C0A[Basic Information<br/>Cluster]
    EP0 --> C0B[Network Commissioning<br/>Cluster]
    EP0 --> C0C[Administrator<br/>Commissioning Cluster]

    EP1 --> C1A[On/Off<br/>Cluster]
    EP1 --> C1B[Level Control<br/>Cluster]
    EP1 --> C1C[Color Control<br/>Cluster]

    C1A --> A1[OnOff<br/>Attribute: bool]
    C1B --> A2[CurrentLevel<br/>Attribute: uint8]
    C1B --> A3[MaxLevel<br/>Attribute: uint8]
    C1C --> A4[CurrentHue<br/>Attribute: uint8]

    C1A --> CMD1[Toggle<br/>Command]
    C1B --> CMD2[MoveToLevel<br/>Command]
    C1C --> CMD3[MoveToHue<br/>Command]

    style Node fill:#16A085,stroke:#2C3E50,color:#fff
    style EP0 fill:#E67E22,stroke:#2C3E50,color:#fff
    style EP1 fill:#E67E22,stroke:#2C3E50,color:#fff
    style EP2 fill:#E67E22,stroke:#2C3E50,color:#fff
    style C0A fill:#2C3E50,stroke:#16A085,color:#fff
    style C0B fill:#2C3E50,stroke:#16A085,color:#fff
    style C0C fill:#2C3E50,stroke:#16A085,color:#fff
    style C1A fill:#2C3E50,stroke:#16A085,color:#fff
    style C1B fill:#2C3E50,stroke:#16A085,color:#fff
    style C1C fill:#2C3E50,stroke:#16A085,color:#fff

Figure 1027.3: Matter Data Model hierarchy: Node to Endpoints to Clusters to Attributes and Commands

{fig-alt=“Matter Data Model hierarchy showing Node at top containing multiple Endpoints, each Endpoint containing Clusters, and each Cluster containing Attributes and Commands. Example shows a smart light with Endpoint 0 for utility clusters and Endpoint 1 for On/Off, Level Control, and Color Control clusters with their respective attributes and commands.”}

1027.5.2 Nodes

A Node is a uniquely addressable Matter entity—typically a physical device.

Node Properties: - Unique Node ID within a fabric (64-bit) - One or more Endpoints (functional units) - Network address (IPv6) - Cryptographic identity (device certificate)

Node Examples: | Physical Device | Matter Node | |—————–|————-| | Smart light bulb | Single node, 1-2 endpoints | | Smart power strip (4 outlets) | Single node, 4 endpoints | | Thread Border Router | Single node, bridge endpoint |

1027.5.3 Endpoints

An Endpoint is a logical container for related functionality within a node.

Standard Endpoints: | Endpoint | Purpose | Required Clusters | |———-|———|——————-| | Endpoint 0 | Root/Utility | Basic Information, Network Commissioning | | Endpoint 1+ | Application functions | Device-specific clusters |

Example: Smart Light with Nightlight

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graph TB
    Node[Node: Smart Bulb]

    subgraph EP0["Endpoint 0: Root (mandatory)"]
        C0A[Basic Information Cluster]
        C0B[Network Commissioning Cluster]
        C0C[Administrator Commissioning Cluster]
    end

    subgraph EP1["Endpoint 1: Main Light"]
        C1A[On/Off Cluster]
        C1B[Level Control Cluster]
        C1C[Color Control Cluster]
    end

    subgraph EP2["Endpoint 2: Nightlight"]
        C2A[On/Off Cluster]
        C2B[Level Control Cluster<br/>limited range]
    end

    Node --> EP0
    Node --> EP1
    Node --> EP2

    style Node fill:#16A085,stroke:#2C3E50,color:#fff
    style EP0 fill:#E67E22,stroke:#2C3E50,color:#fff
    style EP1 fill:#E67E22,stroke:#2C3E50,color:#fff
    style EP2 fill:#E67E22,stroke:#2C3E50,color:#fff
    style C0A fill:#2C3E50,stroke:#16A085,color:#fff
    style C0B fill:#2C3E50,stroke:#16A085,color:#fff
    style C0C fill:#2C3E50,stroke:#16A085,color:#fff
    style C1A fill:#2C3E50,stroke:#16A085,color:#fff
    style C1B fill:#2C3E50,stroke:#16A085,color:#fff
    style C1C fill:#2C3E50,stroke:#16A085,color:#fff
    style C2A fill:#2C3E50,stroke:#16A085,color:#fff
    style C2B fill:#2C3E50,stroke:#16A085,color:#fff

Figure 1027.4: Smart Light endpoint structure with main light and nightlight as separate endpoints

{fig-alt=“Smart Light endpoint structure diagram showing Node (Smart Bulb) in teal at top connecting to three endpoints in orange: Endpoint 0 (Root) containing Basic Information, Network Commissioning, and Administrator Commissioning clusters in navy; Endpoint 1 (Main Light) containing On/Off, Level Control, and Color Control clusters in navy; Endpoint 2 (Nightlight) containing On/Off and Level Control clusters with limited range in navy.”}

1027.5.4 Clusters

A Cluster is a collection of related attributes and commands representing a specific capability.

Cluster Types:

Category	Cluster Examples	Purpose
Utility	Basic Information, Binding	Device management
Lighting	On/Off, Level Control, Color Control	Light operations
HVAC	Thermostat, Fan Control	Climate control
Closure	Door Lock, Window Covering	Access and privacy
Sensors	Temperature, Humidity, Occupancy	Environmental data

Cluster Structure:

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graph LR
    subgraph OnOff["On/Off Cluster (0x0006)"]
        A1[OnOff<br/>Attribute 0x0000<br/>Type: Boolean]
        A2[GlobalSceneControl<br/>Attribute 0x4000<br/>Type: Boolean]
        C1[Off<br/>Command 0x00]
        C2[On<br/>Command 0x01]
        C3[Toggle<br/>Command 0x02]
        E1[StateChange<br/>Event]
    end

    style OnOff fill:#2C3E50,stroke:#16A085,color:#fff
    style A1 fill:#16A085,stroke:#2C3E50,color:#fff
    style A2 fill:#16A085,stroke:#2C3E50,color:#fff
    style C1 fill:#E67E22,stroke:#2C3E50,color:#fff
    style C2 fill:#E67E22,stroke:#2C3E50,color:#fff
    style C3 fill:#E67E22,stroke:#2C3E50,color:#fff
    style E1 fill:#7F8C8D,stroke:#2C3E50,color:#fff

Figure 1027.5: On/Off Cluster structure with attributes, commands, and events

{fig-alt=“On/Off Cluster structure diagram showing cluster ID 0x0006 containing: two attributes in teal (OnOff boolean 0x0000, GlobalSceneControl boolean 0x4000), three commands in orange (Off 0x00, On 0x01, Toggle 0x02), and one event in gray (StateChange). Demonstrates cluster organization with IDs and types.”}

1027.5.5 Attributes

Attributes are named, typed data values within a cluster:

Property	Description	Example
ID	Unique within cluster	0x0000 (OnOff)
Type	Data type	Boolean, uint8, string
Access	Read/Write permissions	R, RW
Quality	Nullable, Reportable, Persistent	Reportable

Common Attribute Types: - Boolean - true/false (On/Off state) - uint8 - 0-255 (brightness level) - int16 - -32768 to 32767 (temperature x 100) - string - Variable length (device name) - struct - Complex objects (color XY) - list - Arrays (supported features)

1027.5.6 Commands

Commands are actions that can be invoked on a cluster:

Property	Description
ID	Unique command identifier within cluster
Direction	Client-to-Server or Server-to-Client
Fields	Input parameters
Response	Expected response command

Example: MoveToLevel Command

Command: MoveToLevel (0x00)
Direction: Client -> Server
Fields:
  - Level (uint8): Target brightness 0-254
  - TransitionTime (uint16): Transition time in tenths of seconds
  - OptionsMask (uint8): Override options
  - OptionsOverride (uint8): Override values
Response: None (status only)

1027.6 Worked Example: Matter Device Type Implementation

NoteWorked Example: Designing a Smart Light Endpoint Structure

Scenario: You are designing a Matter-compatible smart light bulb with dimming and color temperature control. Define the endpoint structure, required clusters, and attribute implementation following Matter specification.

Given: - Device: Dimmable Color Temperature Light - Matter device type: 0x010C (Color Temperature Light) - Required features: On/Off, Brightness (0-254), Color Temperature (2700K-6500K) - Transport: Thread (802.15.4) - Target certification: Matter 1.2

Steps:

1. Define endpoint structure:

   Figure 1027.6

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   graph TB
       Node[Node: Smart Light Bulb]

       subgraph EP0["Endpoint 0: Root (Utility - mandatory)"]
           C0A["Basic Information Cluster (0x0028)"]
           C0B["General Commissioning Cluster (0x0030)"]
           C0C["Network Commissioning Cluster (0x0031)"]
           C0D["Administrator Commissioning Cluster (0x003C)"]
           C0E["Operational Credentials Cluster (0x003E)"]
       end

       subgraph EP1["Endpoint 1: Light (Application)"]
           C1A["Identify Cluster (0x0003)"]
           C1B["Groups Cluster (0x0004)"]
           C1C["On/Off Cluster (0x0006)"]
           C1D["Level Control Cluster (0x0008)"]
           C1E["Color Control Cluster (0x0300)"]
       end

       Node --> EP0
       Node --> EP1

       style Node fill:#16A085,stroke:#2C3E50,color:#fff
       style EP0 fill:#E67E22,stroke:#2C3E50,color:#fff
       style EP1 fill:#E67E22,stroke:#2C3E50,color:#fff
       style C0A fill:#2C3E50,stroke:#16A085,color:#fff
       style C0B fill:#2C3E50,stroke:#16A085,color:#fff
       style C0C fill:#2C3E50,stroke:#16A085,color:#fff
       style C0D fill:#2C3E50,stroke:#16A085,color:#fff
       style C0E fill:#2C3E50,stroke:#16A085,color:#fff
       style C1A fill:#2C3E50,stroke:#16A085,color:#fff
       style C1B fill:#2C3E50,stroke:#16A085,color:#fff
       style C1C fill:#2C3E50,stroke:#16A085,color:#fff
       style C1D fill:#2C3E50,stroke:#16A085,color:#fff
       style C1E fill:#2C3E50,stroke:#16A085,color:#fff

Matter Color Temperature Light device type endpoint structure with cluster IDs

{fig-alt=“Matter Color Temperature Light endpoint structure showing Node (Smart Light Bulb) in teal connecting to two endpoints in orange: Endpoint 0 (Root/Utility) containing five utility clusters with their hex IDs (Basic Information 0x0028, General Commissioning 0x0030, Network Commissioning 0x0031, Administrator Commissioning 0x003C, Operational Credentials 0x003E) in navy; Endpoint 1 (Light Application) containing five application clusters (Identify 0x0003, Groups 0x0004, On/Off 0x0006, Level Control 0x0008, Color Control 0x0300) in navy.”} :::

2. Implement On/Off Cluster (0x0006):
   • Attributes:
     • OnOff (0x0000): Boolean, read-only, reportable
     • GlobalSceneControl (0x4000): Boolean
   • Commands:
     • Off (0x00): Turn light off
     • On (0x01): Turn light on
     • Toggle (0x02): Toggle current state
   • Implementation: GPIO control to LED driver enable pin
3. Implement Level Control Cluster (0x0008):
   • Attributes:
     • CurrentLevel (0x0000): uint8 (0-254), read-only, reportable
     • MinLevel (0x0002): uint8 = 1
     • MaxLevel (0x0003): uint8 = 254
     • OnLevel (0x0011): uint8 (level when turned on)
   • Commands:
     • MoveToLevel (0x00): Level, TransitionTime, OptionsMask
     • Move (0x01): MoveMode, Rate
     • Step (0x02): StepMode, StepSize, TransitionTime
   • Implementation: PWM duty cycle control (0.4% to 100%)
4. Implement Color Control Cluster (0x0300) for Color Temperature:
   • Attributes:
     • ColorMode (0x0008): enum8 = 2 (Color Temperature mode)
     • ColorTemperatureMireds (0x0007): uint16, read-only, reportable
     • ColorTempPhysicalMinMireds (0x400B): uint16 = 153 (6500K)
     • ColorTempPhysicalMaxMireds (0x400C): uint16 = 370 (2700K)
   • Commands:
     • MoveToColorTemperature (0x0A): ColorTemperature, TransitionTime
   • Implementation: Dual-channel LED driver (warm + cool white mixing)
   • Conversion: Mireds = 1,000,000 / Kelvin

Result: Smart light implements Matter device type 0x010C with full dimming (0-254) and color temperature (2700K-6500K) support. Endpoint 0 handles commissioning and network management. Endpoint 1 provides application-level light control through On/Off, Level Control, and Color Control clusters.

Key Insight: Matter’s cluster-based architecture enables interoperability by standardizing behavior. Any Matter controller (Apple, Google, Amazon) can control this light identically because the On/Off, Level Control, and Color Control clusters have standardized attribute types, command formats, and expected behaviors defined in the Matter specification.

1027.7 Knowledge Check

WarningQuick Assessment

NoteAuto-Gradable Questions

Question 1: In Matter’s protocol stack, which layer is responsible for ensuring reliable message delivery over UDP?

B. The Message Reliable Protocol (MRP) in the Transport Layer provides acknowledgments, retransmission, and deduplication to ensure reliable delivery over connectionless UDP.

Question 2: How should a smart power strip with 4 individually controllable outlets be modeled in Matter?

D. Each independently controllable outlet should be its own endpoint with its own On/Off cluster. Endpoint 0 is always required for utility clusters. This allows controllers to address each outlet separately.

Question 3: What is the correct data type for the CurrentLevel attribute in the Level Control cluster?

C. CurrentLevel is a uint8 with valid range 0-254. The value 255 is reserved. This 8-bit representation balances precision with bandwidth efficiency for constrained devices.

1027.8 Key Takeaways

TipSummary

1. Matter’s protocol stack provides end-to-end interoperability from physical transport through application data models

2. The Data Model hierarchy is: Node (device) -> Endpoints (functional units) -> Clusters (capabilities) -> Attributes/Commands (data/actions)

3. Endpoint 0 is mandatory on every device for utility functions (Basic Info, Network Commissioning, Administrator Commissioning)

4. Clusters are reusable building blocks - the same On/Off cluster works identically on lights, plugs, fans, and any on/off device

5. MRP (Message Reliable Protocol) provides reliable delivery over UDP with acknowledgments, retransmission, and deduplication

6. Transport flexibility - Matter works over Thread (low-power mesh), Wi-Fi (high bandwidth), and Ethernet (wired reliability)

1027.9 What’s Next

Continue your Matter architecture deep-dive with:

• Matter Interactions and Commissioning - Learn how controllers read, write, subscribe, and invoke commands
• Matter Fabric and Security - Understand multi-admin, CASE/PASE, and encryption
• Matter Device Types and Clusters - Explore the complete cluster library