Integration at Home - SOA Architecture
Information Management Online, December 6, 2007
This month's column was contributed by Yogish Pai, Integration Consortium member and service-oriented architecture (SOA) practitioner.
Overview on Home Integration
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It all started when Microsoft came out with Universal Plug and Play (UPnP) capabilities to allow users to dynamically plug-in new devices such as mouse, keyboards, external storage, etc. As broadband started being widely adopted and people started having more than one PC at home, the network/wireless hubs also became popular within households. This required the device manufactures to adopt a standard for dynamic discovery, control, event notification, presentation, etc. As the PCs and all their peripherals were already supporting UPnP, it became the choice by default. UPnP is the architecture for peep-to-peer networking of PCs, networked appliances and wireless devices. It is a distributed, open architecture based on TCP/IP, UDP and HTTP.
Next came all the gaming consoles with internet connections and, as the networks hubs (both wired and wireless) were the gateways to the internet, these devices also started supporting UPnP. After the first major release of the gaming consoles, the subsequent releases started adding additional multimedia capabilities. These same capabilities were also available on PCs (and Macs) the storage requirements for households increased exponentially to store all the picture, music and video, personal documents, etc. Today these storage devices also come with multimedia and Web servers to present the content on demand to the user. Once again, the device manufactures leveraged UPnP not only to discover the devices and services but to control access to remote drives, files and control the audio and video play.
At the same time, the mobile phone devices had implemented Bluetooth a low-power, short-range wireless personal area network for exchanging information between devices such as mobile phones, laptops, PCs, digital cameras and video game consoles. As this was short range, most of the Bluetooth devices were the clients interacting with a server such as PCs and game consoles sending commands. These servers would, in turn, leverage UPnP if they needed to access or control remote content.
Until recently, the home automation technology was very expensive and not affordable by most of the households. With the introduction of ZigBee and Wibree low cost chips, the home automation industry has taken off. Home automation is not just for environment control such as light and temperature control, it has also expanded to control audio and video devices – all based on the IP networks. Basically the chip technology allows for control from the server to the client such as light switch, garage door and temperature controller. The servers leverage UPnP to control access to remote services, those not directly connected to the server the user is interacting with.
Basically UPnP is the underlying protocol that provides peer-to-peer networking capabilities within the household. However, due to some limitations of this protocol, Microsoft along with some of its partners proposed a new device profile Web services (DPWS) standard to replace UPnP. As this is not currently backward compatible with UPnP, all vendors are expected to support both UPnP and DPWS until there is convergence.
Independent of the protocol, the home integration is now real which unifies the PCs, gaming consoles and home automation from a console on any device.
Peer-to-Peer Network Overview
The concept of the P2P network is pretty straight forward. Whenever a peer joins a network, it multicasts its availability which triggers interaction between it and the other peers to acknowledge its existence and maintain the peer map. In addition, the peers may exchange device description, control information such as commands available. Once the peer network is established, the clients on any of these devices could control any remote device/resource. All these remote devices/resources could also be referred to as services available on the peer network.
One of the major limitations today is that these protocols used at home only support access from within the local network, i.e., the user cannot access these services from outside the house. The vendors are now actively working on expanding the standard to support remote secure access to these personal home integration services.
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