The AllJoyn® network architecture is dependent upon the network deployment scenario. This section captures the following deployment scenarios:
- Standalone AllJoyn network: A proximal network with a set of peer devices which could be connected over the same or different access mediums.
- Remote accessible AllJoyn network: A proximal network where services provided by devices are accessible and controllable from outside the proximal network.
Standalone AllJoyn network
A standalone AllJoyn network architecture is fairly simple with two or more peer nodes coming together to dynamically form an AllJoyn network. Peers can be connected over different access networks such as Wi-Fi. The AllJoyn advertisement and discovery mechanism takes care of seamlessly discovering these peers independent of the underlying transport being used.
The following figure captures the network architecture for a typical standalone AllJoyn network.
Figure: Standalone AllJoyn network architecture
NOTE: In a Wi-Fi deployment, the AllJoyn framework requires wireless isolation to be turned off at the access points to enable peer-to-peer communication.
Bridging multiple transports
A standalone AllJoyn network can involve nodes connected over both wireless and wired transport, e.g., nodes connected over Wi-Fi, PLC, and Ethernet. Nodes in such a network can communicate with each other as long as wireless isolation is not enabled on the Wi-Fi Access Point (AP).
The following figure captures the high-level network architecture for an AllJoyn network with devices connected over Wi-Fi, PLC, and Ethernet transports.
Figure: Bridging multiple transports
Remote accessible AllJoyn network
A remote accessible AllJoyn network is a proximal IoE network where services provided by devices are accessible and/or controllable from outside the proximal IoE network. The remote accessibility is achieved by having a Gateway node in the system. The Gateway node exposes device functionality and control to an existing cloud-based service either via standard Internet style APIs (e.g. REST). A mobile device outside the proximal IoE network can communicate with devices in the proximal IoE network via the cloud-based service and via the Gateway node.
The following figure captures the high-level network architecture for a remote accessible AllJoyn network.
Figure: Remote accessible AllJoyn network architecture
An AllJoyn-enabled device can support one or more AllJoyn applications. The AllJoyn router can be bundled with each of these applications on devices such as mobile phone and tablets. Alternately, the AllJoyn router can be installed separately as a standalone router on the device and multiple applications can make use of it; examples of devices include TVs and set-top boxes (STBs). There can also be hybrid deployment cases where a single device has both a bundled AllJoyn router for certain apps and a standalone AllJoyn router for other apps on the device.
NOTE; An app always looks for a preinstalled AllJoyn core, so this will only happen if the preinstalled AllJoyn core was a lower version than the bundled AllJoyn core.
The following deployment scenarios are captured for the AllJoyn device:
- Single app with bundled AllJoyn router
- Multiple apps with bundled AllJoyn router
- Multiple apps with standalone AllJoyn router
Single app with bundled AllJoyn router
In this deployment, the AllJoyn application package includes an app and an AllJoyn router. The app can support application-specific services as well as one or more service frameworks. The application connects to the AllJoyn router via the AllJoyn standard core library. In case of the bundled AllJoyn router, the communication between the app and AllJoyn router is local (within the same process) and can be done using function/API calls.
The following figure captures the AllJoyn device architecture for a single app with bundled AllJoyn router deployment scenario.
Figure: AllJoyn device architecture (single app with bundled AllJoyn router)
Multiple apps with bundled AllJoyn router
In this deployment, the AllJoyn-enabled device supports multiple applications. Each of these applications has a separate instance of an AllJoyn router bundled with that application package.
The following figure captures the AllJoyn device architecture for multiple apps with a bundled AllJoyn router deployment scenario.
Figure: AllJoyn device architecture (multiple apps with bundled AllJoyn router)
Multiple apps with standalone AllJoyn router
In this deployment, the AllJoyn-enabled device supports a standalone AllJoyn router. The multiple applications on the device connect using the same standalone AllJoyn router. The communication between an application and the standalone AllJoyn router happens across process boundaries and can happen over transports like UNIX domains sockets or TCP.
The following figure captures the AllJoyn device architecture for multiple apps with a standalone AllJoyn router deployment scenario.
Figure: AllJoyn device architecture (multiple apps with standalone AllJoyn router)
AllJoyn router architecture
The AllJoyn router provides a number of functionalities to enable key features of the AllJoyn framework. The following figure captures the functional architecture for the AllJoyn router.
Figure: AllJoyn router functional architecture
The AllJoyn router supports key features over multiple underlying transports. The Advertisement and Discovery module provides transport agnostic advertisement and discovery functionality. Similarly, modules shown for other features including Session, Data Exchange, and Sessionless Signal modules offer transport-agnostic functionality for those features. All these AllJoyn features work over various transports including Wi-Fi, wired transports, Bluetooth, and any local transport.
The AllJoyn bus management and control functions are provided by the Bus Management module. The Security module provides AllJoyn security functionality including SASL-based authentication.
The Message and Signal Transport layer provides functionality to encapsulate application layer signaling and data into D-Bus format message encapsulation. The Transport Abstraction Layer provides abstraction for various underlying transports for core AllJoyn features. The various transport-related modules provide that transport-specific functionality to accomplish core AllJoyn functions. The AllJoyn router supports an OS Abstraction Layer to interact with different underlying OS platforms.
Thin app architecture
An AllJoyn thin app is designed for energy-, memory-, and CPU-constrained devices. The thin app is designed to have a very small memory footprint and is typically single-threaded. The thin app includes the application code and AllJoyn thin core library (AJTCL); it does not include an AllJoyn router.
A thin AllJoyn device only has a lightweight thin app running on the device that makes use of an AllJoyn router running on a standard AllJoyn device to advertise, discover, and connect with AllJoyn peers. Communication between the thin app and the AllJoyn router occurs across device boundaries over TCP transport.
The following figure captures the AllJoyn thin app architecture.
Figure: AllJoyn thin app architecture
AllJoyn framework protocol stack
The following figure captures the high-level protocol stack for the AllJoyn framework.
Figure: AllJoyn protocol stack
At the top level, the AllJoyn framework protocol stack consists of an application providing a number of application layer services and supporting some service frameworks. These app layer services are defined by AllJoyn interfaces supported by the app. The app sits on top of the AllJoyn core library, which enables an app to invoke core AllJoyn functionality.
Below the AllJoyn core library sits the AllJoyn router that implements core AllJoyn features including advertisement/discovery, session establishment, sessionless signals, authentication, etc. The AllJoyn router supports multiple underlying transports for discovery and communication and provides an abstraction layer for each of the supported transport. The AllJoyn router belongs to the application layer in the standard OSI layering model.
Under the AllJoyn router reside the standard OSI layers: transport, network, layer 2 and physical layer.