Creating and Deploying a Drop-in Network
- Tuesday, 25 November 2008
Companies are constantly looking for ways to monitor and track the critical device information that resides in their remote assets. They also need to understand the environments in which their devices reside. But why? The traditional method for remote device management is to send technicians to remote sites to gather information. This can be expensive and labor-intensive. As a result, organizations need to have a strong reason to gather remote device information; otherwise, it just doesn’t happen. This article will take a modern view of remote device management — what is it and why is it important? We will discuss the modern, cost-effective method of remote device management known as Drop-in Networking, and important considerations in creating a Drop-in Network.
Remote Device Management
In business, the world revolves around increasing profitability, and increased profitability comes from new and increased revenue sources and/or increased operating efficiency driving lower costs. In order to have new revenue, you must have something to sell and in order to increase efficiency, you must be able to identify the areas of inefficiency.
So, in the world of remote device management, the goal is to measure and control remote devices by enabling communication with a back-end application, thereby enabling new revenue sources and/or increasing efficiency. It sounds easy, and if the device is intelligent and networked, it is easy in general terms. However, if the device is something that is not easily connected because access to a network is not available, it doesn’t generally matter how intelligent the device or the application is — the data isn’t accessible from a central location (see Figure 1).
Early on, remote device management was mostly concerned with managing devices and environments that already were wired. Further, where there wasn’t an infrastructure, the proverbial human-based “sneaker-net” has been pretty effective to handle the necessary communication. However, it has not been enough to truly drive efficiency and new revenue.
What is a Drop-In Network?
What does this all mean in the world of industrial and commercial areas? As advancements in wireless technology have caused the wired paradigm to fade, and as pervasive wireless in consumer markets has driven our belief in easy, lowcost solutions, we need to remember that commercial needs are different. We can’t always rely on the human presence to adjust for the “number of bars” or to initiate a “new call.” We also need to account for the relatively small number of devices in a consumer application environment compared to the thousands of units in a commercial or industrial environment. There are millions of consumer devices, but each of us still only has a handful to manage. Finally, we need to acknowledge that reliability and mission-critical needs have an impact and a cost. As such, we are forced to ask if a wireless solution in the commercial and industrial world can be cost-effective. Because of recent wireless innovations, the way organizations gather information to improve operations is changing.
A Drop-in Network enables end-toend
wireless access to electronic devices
in isolated, hard-to-reach locations. By
addressing the challenge of networking
devices where wireline infrastructure is
unavailable, Drop-in Networking promises
to revolutionize the way that companies
apply technology to improve asset
utilization and deliver smarter service
solutions. This concept includes both
hardware devices and software tools that
allow customers to “drop-in” customized
wireless networks for monitoring and
control applications across a broad
range of vertical markets. Key features of
a Drop-in Network include:
- Power-optimized — supports sleeping end nodes that are often battery powered
- Cost-effective — requires no new cabling
Figure 2 illustrates the components of a Drop-in Network, which generally includes a device connectivity component through a personal area network (PAN) and/or local area network (LAN) back to a programmable gateway aggregation point. Information is then sent over a WAN to a remote application. Note that the goal of the devices’ PAN/LAN is to relay data between the devices and the on-site aggregation point. The gateway is used to move data from a low-level device view to a Web services-based framework using efficient, conventional Web programming languages like Python.
Creating a Drop-In Network
In order to create a Drop-In Network,
there are a few guiding principles:
- Define how the application should work.
- Choose the connectivity technology.
- Design the network and place the parts.
- Bring the data home.
1. Define how the application should work. It is important to assess the end-to-end functionality, level of service, location of intelligence, and level of security. The question of functionality usually relates to whether the application is for logging, control, alarming, or all of them. Level of service involves whether the data is mission-critical or best-attempt. This helps drive where intelligence should be placed. As a general rule, intelligence can be placed at the device, at an intermediate point, or at the enterprise. It is generally unwise to put intelligence everywhere, and mission-critical communication almost always requires intelligence at the end device. Security should then be overlayed on top by evaluating what happens if the system is compromised from both an access and eavesdropping perspective.
2. Choose the most effective connectivity technology. What’s already in place? Evaluate the environment for what already exists. This includes whether there are any opportunities to use existing cabled communications and local power, as well as the availability of wireless infrastructure like Wi-Fi and cellular signal strength. Next, assess the best ways to fill in the gaps. With the application needs determined and the available infrastructure evaluated, it is time to complete the puzzle. This now involves doing an environmental assessment, site survey, and cost trade-offs for different deployment options. Here it is important to note that choosing the wrong wireless connectivity will make the solution cost-ineffective and harder to manage. Hence, you must understand data flow, latency needs, reliability needs, range, scalability, and power availability.
3. Design the network and place the parts. Once the connectivity technology has been chosen, it is time for the detailed design work. Note that poor RF performance will make the solution costineffective, harder to manage, and unreliable. Hence, it is important to understand RF barriers and constraints. Survey the area to work around obstacles if necessary. This will again require a site survey to help with placement of the network components in order to maximize data flow and meet the reliability requirements. It also means mapping to meaningful things. Auto deployment can only go so far. Applications only work if the name matches the location. This means that you must determine the naming methodology that best suits the existing process.
4. Bring the data home. Data is only useful if it gets to and from the host application. This means that we need to decide what data is critical up front and then design a system that is easy for an IT group to maintain in the long term. The best way to do this is to deliver the data in a standardized form consistent with off-the-shelf database constructs. This is easiest to do by creating a data access service model using off-the-shelf Web services and often requires a database conversion to get around the challenges of pulling data from remote locations where conventional IP routing may not be available. Figure 3 illustrates this model with a gateway on the left forwarding data to a centralized XML based repository, accessible across the broader Internet via secure Web services queries.
Given the value proposition of effective remote device management, we have defined a concept of a Drop-in Network to meet the needs where traditional wired connectivity does not exist or is not available. Using a combination of wireless technology and a structured data definition for the application at hand, a solution can be deployed using off-the-shelf Web services-based applications. The key is to follow a welldefined methodology of defining the needs, assessing the environment, choosing the best wireless technology, designing the network, and then bringing the data home.
This article was written by Joel K. Young, Senior Vice President of Research and Development and CTO, Digi International, Minnetonka, MN. For more information, click here.