RIPlink: gateways that harness the power of Internet Protocol for efficient Zigbee and PLC networks

By Wavecom

The majority of communication systems are now designed around Internet Protocol (IP), which is the most standard and widely deployed architecture. By defining a clear separation between networks and services, IP offers interoperability and extensibility, resulting in lower up-front investments, maintenance cost savings and future-proofing of long-life products. M2M (machine-to-machine) applications remain the exception to the rule since they do not yet widely use IP technology. One of the reasons is that many M2M solutions cannot efficiently support IP from end-to-end. The burden on resource-constrained devices and limited bandwidth networks has until now been considered a show stopper.

To overcome the technological barriers that currently limit connected M2M growth, Wavecom has designed an innovative technology that extends IP networks’ reach to low-resource machines. This Remote IP – RIPlinkTM – technology was designed specifically to save resources (memory, CPU, battery life, bandwidth) while enabling standard TCP and UDP applications to be ported on any device and connected over any non-IP network. This includes in particular low power RF networks, such as ZigBee or Power Line Communication (PLC) wired networks.

Thanks to a RIPlink Gateway device that is connected on one side to the IP network, and on the other side to one or more non-IP networks, standard TCP or UDP applications can run on non-IP devices  and have access to the IP network resources. No IP stack is required on the device since the underlying non-IP network remains unchanged. The application on the device is independent from the non-IP network, in the same way that IP applications are independent from their underlying IP network.

With RIPlink, IP solutions can easily operate over heterogeneous IP and non-IP networks. For example, the same application designs can directly be ported straight from one network environment to another.

Why IP, why RIPlink?

Choosing a communication technology
Machine-to-machine (M2M) solutions, by definition require “inter-connecting” machines. The choice of the communication technologies is complex, and key for obtaining the best possible result. It will directly impact the cost (deployment and operation) and the quality of the end solution.

But this choice will also determine how fast and easy, or how long and complex, the application development, porting and evolution will be. Decoupling the communication and the application, with a standard, well-known and future-proof interface is the right way to save development resources, focus on the end solution, and protect the overall investment.

IP is now also the reference architecture for M2M
Internet Protocol (IP) architecture has been for several years now, the undisputed reference for communicating applications. There is no system design today that does not consider inter-connecting to IP.

The range of applications available today on TCP and UDP Transport protocols is almost unlimited, benefitting from a long list of popular application-layer protocols (telnet, FTP, SNMP, POP3/SMTP, HTTP, etc.) and a very strong and active IETF (Internet Engineering Task Force) standardization organisation. The telecom industry has invested significant resources over years to design, validate and deploy a wide range of TCP and UDP-based solutions, both for industrial and consumer applications.

While benefitting from such developments, machine-to-machine (M2M) industry players must invest more in the coming years in communicating application design, to address its fragmented market: automotive Telematics, vehicle and assets tracking, healthcare, metering, payment terminals, vending machines, home and building automation, alarm and security systems, etc. The best way to secure such investment is by relying on the most future-proof communication protocols: TCP and UDP. This is the guaranty for best transition path while communication technologies – in particular wireless – evolve. It will facilitate the integration with existing companies’ information systems, and other machine networks or consumer applications.

RIPlink enables IP applications on any network – easily
RIPlink, standing for Remote IP link, is a technology specifically conceived to allow standard TCP/UDP applications to be run on any non-IP devices and inter-connect over any non-IP and IP networks. RIPlink technology, with its specific Remote Socket Protocol (RSP), offers to the application the same independence to the physical network as regular IP network does.

How RIPlink works?
RIPlink technology relies on a RIPlink Gateway running the IP, TCP and UDP stacks, and connected to IP network or hosting local IP applications. The RSP protocol, acting as a remote procedure call protocol, exposes the RIPlink Gateway TCP/UDP socket Application Programming Interfaces (APIs) to the applications running on RIPlink Devices. RIPlink Device does not need any IP, TCP nor UDP stack, but simply an RSP Client.

RIPlink Device and Gateway Device – Layers view

The IP application running on the RIPlink Device is seen from the IP network as running on a port of the RIPlink Gateway. It can be a client or a server application.

Several IP applications can run on the same RIPlink Device. The RIPlink Gateway can manage simultaneously several RIPlink Devices, on one or more different non-IP networks.

RIPlink Reference Architecture
The RIPlink Reference Architecture defines software components and interfaces, to allow modular and interoperable implementation of RIPlink across various devices and non-IP networks.

The RIPlink Reference Architecture software components are:

• The RSP Gateway which is part of the RIPlink Gateway is independent from the non-IP network. RSP Gateway does interface to the RIPlink Gateway TCP/UDP/IP stack. RSP Gateway implements the Remote Socket Protocol server side.
• The RSP Client which is part of the RIPlink Device and is independent from the non-IP network. RSP Client exposes the RIPlink socket APIs to the IP Application running on RIPlink Device. RSP Client implements the Remote Socket Protocol client side.
• The Gateway Adapter and Client Adapter are respectively part of RIPlink Gateway and RIPlink Device, and dependent of the non-IP network. They perform a reliable transport channel of the Remote Socket Protocol between RSP Client and RSP Gateway, adapted to the non-IP network specificities. Gateway Adapter manages in addition non-IP network specific addressing.

RIPlink Reference Architecture allows easy integration and testing of various RIPlink building components to form a complete system, mapped onto various hardware architectures. Thanks to RSP protocol, Gateway Adapter and RSP Gateway may run on different processors, as well as Client Adapter and RSP Client. Thanks to CRSP API specification, Client Adapter and RSP Client can be integrated as two well defined software components. Of course, it is developer choice to follow or not the specification for interfaces that would remain internal to an implementation.

RSP Protocol
RIPlink relies on the Remote Socket Protocol (RSP), specifically designed for RIPlink technology. RSP is a simple protocol including RIPlink Gateway and Device binding management (GW_INIT, BIND, etc.), socket management commands (CONNECT, LISTEN, CLOSE, etc.) and commands for TCP and UDP data sending (TSEND, USEND, etc.). Exact same RSP protocol is used whatever the non-IP network. However, the way RSP is transported over a non-IP network may be adapted to optimize its efficiency.

The flow chart below illustrates how RSP protocol can be used to connect to a TCP server, exchange data over that connection, and close that connection.

RIPlink applications

Wavecom RIPlink Gateway demonstration on ZigBee
To demonstrate RIPlink efficiency and simplicity, Wavecom has developed a simple home alarm application using RIPlink (i.e. implementing RSP protocol), ZigBee and GPRS technologies.
The demonstration involves ZigBee sensors, a GPRS-ZigBee gateway built on Wavecom Fastrack Supreme product, a back-end server, and standard laptop and handset equipment.
The application is using an event management client-server light protocol developed by Wavecom, named M2M Service Agent (M2M-SA), and running on top of TCP/IP, thus also on top of RIPlink.

The application (the M2M-SA Client) running on each simple ZigBee sensors, report the sensor state change (the events) to a small light server (the M2M-SA Server) embedded into the Wavecom Gateway. The M2M-SA protocol is transported over ZigBee thanks to RIPlink, without any change or adaptation compared to its transport over regular IP network, GPRS for example. The same M2M-SA protocol is used to report event changes to the M2M-SA Server running in the back-end. Any device (laptop, mobile, etc.) on the IP network can be informed immediately of sensors state changes.

RIPlink over ZigBee demonstration for Home Alarm application

RIPlink based concentrator in Smart Metering

RIPlink perfectly answers to the increasing demand in smart metering for interconnecting a variety of devices (data loggers, meters, home displays, domestic appliances, etc.) to an information system, by offering IP end-to-end.

A typical implementation of RIPlink is depicted below for a multi-energy smart metering infrastructure. GPRS cellular network access is used by concentrators, home gateways or meters to connect to the information system through IP. This IP network is then extended over Power Line Communication (PLC), or over low power RF technologies (ZigBee or any proprietary technology) to electricity meters, water and gas meters, but also domestic appliances. With RIPlink, the same IP application can run on all meters for data collection, whatever the retained architecture. As RIPlink is not exclusive, a standard ZigBee application can also be deployed when preferred.

RIPlink in Smart Metering

RIPlink eco-system
After having designed and demonstrated RIPlink, Wavecom is contributing to turn RIPlink into an industry standard, with an eco-system of companies developing RIPlink based solutions. This eco-system will provide software, tools or complete products to allow fast deployment of RIPlink Devices and RIPlink Gateways, on a variety of bearers.

Wavecom contributes in particular by publishing RIPlink specifications (RIPlink Reference Architecture, RSP protocol, and RSP Client reference interface) and providing some use cases and products. Other companies contribute by making available their software implementation of RIPlink Gateways and Devices, adapted to various non-IP networks such as ZigBee, PLC, or some other low power RF technologies.

Wavecom further contributes by initiating a forum and a wiki to help making RIPlink resources more easily available to all interested M2M companies.

RIPlink Devices design
In order to design the RIPlink Devices that will connect to the RIPlink Gateway over the non-IP network, customers can either rely on RIPlink implementation available from partners, or develop their own RSP Client and Client Adapter based on documentation and sample code available from Wavecom or partners.

Keeping a close eye on remote assets
M2M Gateways in general and RIPlink Gateways in particular, extend the reach to local networks. Such local networks usually require some remote administration capability that can be performed by the M2M Gateway. With Wavecom remote device management service (Wavecom IDS), local network administration can be easily integrated to standard device management, including remote software upgrades of the RIPlink Devices when supported by the local network technology.

A logical leap – linking IP to device management
By expanding IP networks to non-IP network technologies, RIPlink offers a unique opportunity to easily and rapidly develop and deploy IP applications on a variety of heterogeneous machine networks. RIPlink offers a way to better integrate machines to existing systems, thus increasing M2M capabilities and services. By leveraging IP strengths, RIPlink will significantly lower M2M solution design and deployment costs, protect investments, and offer improved time-to-market.

And as interoperability is a key success factor, Wavecom is making RIPlink a freely available technology, to be widely available through a rich eco-system of industry players providing RIPlink solutions.

With its contribution to RIPlink, Wavecom expects M2M market to capture new opportunities and be significantly fostered.

More about RIPlink:
[R1] RIPlink website (Wiki, downloads, FAQs, Blog)... www.wavecom.com/riplink

Contact details:
Sara Brown, Communications Manager
T: +1 919 237 4007, E: sara.brown@wavecom.com, W: www.wavecom.com