Device Servers Tutorial

Reference: http://www.lantronix.com/resources/net-tutor-ds.html


Device Server Technology -
Understanding and Imagining its Possibilities

For easy reference, please consult the glossary of terms at the end of this paper.*
The ability to manage virtually any electronic device over a network or the Internet is changing our world. Companies want to remotely manage, monitor, diagnose and control their equipment because doing so adds an unprecedented level of intelligence and efficiency to their businesses. 
With this trend, and as we rely on applications like e-mail and database management for core business operations, the need for more fully-integrated devices and systems to monitor and manage the vast amount of data and information becomes increasingly more important. And, in a world where data and information is expected to be instantaneous, the ability to manage, monitor and even repair equipment from a distance is extremely valuable to organizations in every sector.
This need is further emphasized as companies with legacy non-networked equipment struggle to compete with organizations equipped with advanced networking capabilities such as machine-to-machine (M2M) communications. There’s no denying that advanced networking provides an edge to improving overall efficiencies.
This tutorial will provide an overview and give examples of how device servers make it easy to put just about any piece of electronic equipment on an Ethernet network. It will highlight the use of external device servers and their ability to provide serial connectivity for a variety of applications. It will touch on how device networking makes M2M communication possible and wireless technology even more advanced. Finally, as any examination of networking technologies requires consideration of data security, this paper will provide an overview of some the latest encryption technologies available for connecting devices securely to the network.

Moving from Serial to Ethernet
An Introduction to Device Server Technology

For some devices, the only access available to a network manager or programmer is via a serial port. The reason for this is partly historical and partly evolutionary. Historically, Ethernet interfacing has usually been a lengthy development process involving multiple vendor protocols (some of which have been proprietary) and the interpretation of many RFCs. Some vendors believed Ethernet was not necessary for their product which was destined for a centralized computer center - others believed that the development time and expense required to have an Ethernet interface on the product was not justified.
From the evolutionary standpoint, the networking infrastructure of many sites has only recently been developed to the point that consistent and perceived stability has been obtained - as users and management have become comfortable with the performance of the network, they now focus on how they can maximize corporate productivity in non-IS capacities.
Device server technology solves this problem by providing an easy and economical way to connect the serial device to the network.
Device Server topology exampleLet's use the Lantronix UDS100 Device Server as an example of how to network a RAID controller serial port. The user simply cables the UDS100 's serial port to the RAID controller's serial port and attaches the UDS100's Ethernet interface to the network. Once it has been configured, the UDS100 makes that serial port a networked port, with its own IP address. The user can now connect to the UDS100 's serial port over a network, from a PC or terminal emulation device and perform the same commands as if he was using a PC directly attached to the RAID controller. Having now become network enabled, the RAID can be managed or controlled from anywhere on the network or via the Internet.
The key to network-enabling serial equipment is in a device server’s ability to handle two separate areas:
  1. the connection between the serial device and the device server
  2. the connection between the device server and the network (including other network devices)
Traditional terminal, print and serial servers were developed specifically for connecting terminals, printers and modems to the network and making those devices available as networked devices. Now, more modern demands require other devices be network-enabled, and therefore device servers have become more adaptable in their handling of attached devices. Additionally, they have become even more powerful and flexible in the manner in which they provide network connectivity.

Device Servers Defined

A device server is “a specialized network-based hardware device designed to perform a single or specialized set of functions with client access independent of any operating system or proprietary protocol.” 
Device servers allow independence from proprietary protocols and the ability to meet a number of different functions. The RAID controller application discussed above is just one of many applications where device servers can be used to put any device or "machine" on the network. 
PCs have been used to network serial devices with some success.  This, however, required the product with the serial port to have software able to run on the PC, and then have that application software allow the PC's networking software to access the application. This task equaled the problems of putting Ethernet on the serial device itself so it wasn’t a satisfactory solution. 
To be successful, a device server must provide a simple solution for networking a device and allow access to that device as if it were locally available through its serial port. Additionally, the device server should provide for the multitude of connection possibilities that a device may require on both the serial and network sides of a connection. Should the device be connected all the time to a specific host or PC? Are there multiple hosts or network devices that may want or need to connect to the newly-networked serial device? Are there specific requirements for an application which requires the serial device to reject a connection from the network under certain circumstances? The bottom line is a server must have both the flexibility to service a multitude of application requirements and be able to meet all the demands of those applications.

Capitalizing on Lantronix Device Server Expertise and Proven Solutions

Lantronix is at the forefront of M2M communication technology.  The company is highly focused on enabling the networking of devices previously not on the network so they can be accessed and managed remotely.

Lantronix has built on its long history and vast experience as a terminal, print and serial server technology company to develop more functionality in its servers that “cross the boundary” of what many would call traditional terminal or print services. Our technology provides:
  • The ability to translate between different protocols to allow non-routable protocols to be routed
  • The ability to allow management connections to single-port servers while they are processing transactions between their serial port and the network
  • A wide variety of options for both serial and network connections including serial tunneling and automatic host connection make these servers some of the most sophisticated Ethernet-enabling devices available today.

Ease of Use

As an independent device on the network, device servers are surprisingly easy to manage. Lantronix has spent years perfecting Ethernet protocol software and its engineers have provided a wide range of management tools for this device server technology. Serial ports are ideal vehicles for device management purposes - a simple command set allows easy configuration. The same command set that can be exercised on the serial port can be used when connecting via Telnet to a Lantronix device server.
An important feature to remember about the Lantronix Telnet management interface is that it can actually be run as a second connection while data is being transferred through the server - this feature allows the user to actually monitor the data traffic on even a single-port server's serial port connection while active. Lantronix device servers also support SNMP, the recognized standard for IP management that is used by many large network for management purposes.
Finally, Lantronix has its own management software utilities which utilize a graphical user interface providing an easy way to manage Lantronix device servers. In addition, the servers all have Flash ROMs which can be reloaded in the field with the latest firmware.

Device Servers for a Host of Applications

This section will discuss how device servers are used to better facilitate varying applications such as:
  • Data Acquisition
  • M2M
  • Wireless Communication/Networking
  • Factory/Industrial Automation
  • Security Systems
  • Bar Code Readers and Point-of-sale Scanners
  • Medical Applications

Data Acquisition

Microprocessors have made their way into almost all aspects of human life, from automobiles to hockey pucks. With so much data available, organizations are challenged to effectively and efficiently gather and process the information. There are a wide variety of interfaces to support communication with devices. RS-485 is designed to allow for multiple devices to be linked by a multidrop network of RS-485 serial devices. This standard also had the benefit of greater distance than offered by the RS-232/RS-423 and RS-422 standards.
However, because of the factors previously outlined, these types of devices can further benefit from being put on an Ethernet network. First, Ethernet networks have a greater range than serial technologies. Second, Ethernet protocols actually monitor packet traffic and will indicate when packets are being lost compared to serial technologies which do not guarantee data integrity.
Lantronix full family of device server products provides the comprehensive support required for network enabling different serial interfaces. Lantronix provides many device servers which support RS-485 and allow for easy integration of these types of devices into the network umbrella. For RS-232 or RS-423 serial devices, they can be used to connect equipment to the network over either Ethernet or Fast Ethernet.

An example of device server collaboration at work is Lantronix's partnership with Christie Digital Systems, a leading provider of visual solutions for business, entertainment and industry. Christie integrates Lantronix SecureBox® secure device server with feature-rich firmware designed and programmed by Christie for its CCM products. The resulting product line, called the ChristieNET SecureCCM, provided the encryption security needed for use in the company’s key markets, which include higher education and government. Demonstrating a convergence of AV and IT equipment to solve customer needs, ChristieNET SecureCCM was the first product of its kind to be certified by the National Institute of Standards and Technology (NIST).

M2M and Wireless Communications

Two extremely important and useful technologies for communication that depend heavily on device servers are M2M and wireless networking.
Made possible by device networking technology, M2M enables serial-based devices throughout a facility to communicate with each other and humans over a Local Area Network/Wide Area Network (LAN/WAN) or via the Internet. The prominent advantages to business include:
  • Serial Tunneling diagramMaximized efficiency
  • More streamlined operations
  • Improved service
Lantronix Device Servers enable M2M communications either between the computer and serial device, or from one serial device to another over the Internet or Ethernet network using “serial tunneling.” Using this serial to Ethernet method, the “tunnel” can extend across a facility or to other facilities all over the globe.
M2M technology opens a new world of business intelligence and opportunity for organizations in virtually every market sector. Made possible through device servers, M2M offers solutions for equipment manufacturers, for example, who need to control service costs. Network enabled equipment can be monitored at all times for predictive maintenance. Often when something is wrong, a simple setting or switch adjustment is all that is required. When an irregularity is noted, the system can essentially diagnose the problem and send the corrective instructions. This negates a time-consuming and potentially expensive service call for a trivial issue. If servicing is required, the technician leaves knowing exactly what is wrong and with the proper equipment and parts to correct the problem. Profitability is maximized through better operating efficiencies, minimized cost overruns and fewer wasted resources.
Traditional Service Model diagram
Remote Mgmt. Service Model diagram
M2M technology also greatly benefits any organization that cannot afford downtime, such as energy management facilities where power failures can be catastrophic, or hospitals who can’t afford interruptions with lives at stake. By proactively monitoring networked-enabled equipment to ensure it is functioning properly at all times, business can ensure uptime on critical systems, improve customer service and increase profitability.

Wireless Networking

Wireless networking, allows devices to communicate over the airwaves and without wires by using standard networking protocols. There are currently a variety of competing standards available for achieving the benefits of a wireless network. Here is a brief description of each:
Bluetooth
is a standard that provides short-range wireless connections between computers, Pocket PCs, and other equipment.
ZigBee
is a proprietary set of communication protocols designed to use small, low power digital radios based on the IEEE 802.15.4 standard for wireless personal area networking.
802.11
is an IEEE specification for a wireless LAN airlink.
802.11b (or Wi-Fi)
is an industry standard for wireless LANs and supports more users and operates over longer distances than other standards. However, it requires more power and storage. 802.11b offers wireless transmission over short distances at up to 11 megabits per second. When used in handheld devices, 802.11b provides similar networking capabilities to devices enabled with Bluetooth.
802.11g
is the most recently approved standard and offers wireless transmission over short distances at up to 54 megabits per second. Both 802.11b and 802.11g operate in the 2.4 GHz range and are therefore compatible.
For more in-depth information, please consult the Lantronix wireless whitepaper which is available online.
Wireless technology is especially ideal in instances when it would be impractical or cost-prohibitive for cabling; or in instances where a high level of mobility is required.
Wireless topology diagram
Wireless device networking has benefits for all types of organizations. For example, in the medical field, where reduced staffing, facility closures and cost containment pressures are just a few of the daily concerns, device networking can assist with process automation and data security. Routine activities such as collection and dissemination of data, remote patient monitoring, asset tracking and reducing service costs can be managed quickly and safely with the use of wireless networked devices. In this environment, Lantronix device servers can network and manage patient monitoring devices, mobile EKG units, glucose analyzers, blood analyzers, infusion pumps, ventilators and virtually any other diagnostic tool with serial capability over the Internet.
Forklift accidents in large warehouses cause millions of dollars in damaged product, health claims, lost work and equipment repairs each year. To minimize the lost revenue and increase their profit margin and administrative overhead, “a company” has utilized wireless networking technology to solve the problem. Using Lantronix serial-to-802.11 wireless device server “the company” wirelessly network-enables a card reader which is tied to the ignition system of all the forklifts in the warehouse. Each warehouse employee has an identification card. The forklift operator swipes his ID card before trying to start the forklift. The information from his card is sent back via wireless network to computer database and it checks to see if he has proper operator’s license, and that the license is current. If so, forklift can start. If not – the starter is disabled.

Factory Floor Automation

For shops that are running automated assembly and manufacturing equipment, time is money. For every minute a machine is idle, productivity drops and the cost of ownership soars. Many automated factory floor machines have dedicated PCs to control them. In some cases, handheld PCs are used to reprogram equipment for different functions such as changing computer numerically controlled (CNC) programs or changing specifications on a bottling or packaging machine to comply with the needs of other products. These previously isolated pieces of industrial equipment could be networked to allow them to be controlled and reprogrammed over the network, saving time and increasing shop efficiency. For example, from a central location (or actually from anywhere in the world for that matter) with network connectivity, the machines can be accessed and monitored over the network. When necessary, new programs can be downloaded to the machine and software/firmware updates can be installed remotely.
One item of interest is how that input programming is formatted. Since many industrial and factory automation devices are legacy or proprietary, any number of different data protocols could be used. Device servers provide the ability to utilize the serial ports on the equipment for virtually any kind of data transaction.
Lantronix device servers support binary character transmissions. In these situations, managing the rate of information transfer is imperative to guard against data overflow. The ability to manage data flow between computers, devices or nodes in a network, so that data can be handled efficiently is referred to as flow control. Without it, the risk of data overflow can result in information being lost or needing to be retransmitted.
Lantronix accounts for this need by supporting RTS/CTS flow control on its DB25 and RJ45 ports. Lantronix device servers handle everything from a simple ASCII command file to a complex binary program that needs to be transmitted to a device.

Security Systems

One area that every organization is concerned about is security. Card readers for access control are commonplace, and these devices are ideally suited to benefit from being connected to the network with device server technology. When networked, the cards can be checked against a centralized database on the system and there are records of all access within the organization. Newer technology includes badges that can be scanned from a distance of up to several feet and biometric scanning devices that can identify an individual by a thumbprint or handprint. Device servers enable these types of devices to be placed throughout an organization's network and allow them to be effectively managed by a minimum staff at a central location. They allow the computer controlling the access control to be located a great distance away from the actual door control mechanism.
An excellent example is how ISONAS Security Systems utilized Lantonix WiPort® embedded device server to produce the World’s first wireless IP door reader for the access control and security industry. With ISONAS reader software, network administrators can directly monitor and control an almost unlimited number of door readers across the enterprise. The new readers, incorporating Lantronix wireless technology, connect directly to an IP network and eliminate the need for traditional security control panels and expensive wiring. The new solutions are easy to install and configure, enabling businesses to more easily adopt access control, time and attendance or emergency response technology. What was traditionally a complicated configuration and installation is now as simple as installing wireless access points on a network.
One more area of security systems that has made great strides is in the area of security cameras. In some cases, local municipalities are now requesting that they get visual proof of a security breach before they will send authorities. Device server technology provides the user with a host of options for how such data can be handled. One option is to have an open data pipe on a security camera - this allows all data to be viewed as it comes across from the camera. The device server can be configured so that immediately upon power-up the serial port attached to the camera will be connected to a dedicated host system.
Another option is to have the camera transmit only when it has data to send. By configuring the device server to automatically connect to a particular site when a character first hits the buffer, data will be transmitted only when it is available.
One last option is available when using the IP protocol - a device server can be configured to transmit data from one serial device to multiple IP addresses for various recording or archival concerns. Lantronix device server technology gives the user many options for tuning the device to meet the specific needs of their application.

Scanning Devices

Device server technology can be effectively applied to scanning devices such as bar code readers or point-of-sale debit card scanners. When a bar code reader is located in a remote corner of the warehouse at a receiving dock, a single-port server can link the reader to the network and provide up-to-the-minute inventory information. A debit card scanner system can be set up at any educational, commercial or industrial site with automatic debiting per employee for activities, meals and purchases. A popular amusement park in the United States utilizes such a system to deter theft or reselling of partially-used admission tickets.

Medical Applications

The medical field is an area where device server technology can provide great flexibility and convenience. Many medical organizations now run comprehensive applications developed specifically for their particular area of expertise. For instance, a group specializing in orthopedics may have x-ray and lab facilities onsite to save time and customer effort in obtaining test results.  Connecting all the input terminals, lab devices, x-ray machines and developing equipment together allows for efficient and effective service. Many of these more technical devices previously relied upon serial communication or worse yet, processing being done locally on a PC. Utilizing device server technology they can all be linked together into one seamless application. And an Internet connection enables physicians the added advantage of access to immediate information relevant to patient diagnosis and treatment.
Larger medical labs, where there are hundreds of different devices available for providing test data, can improve efficiency and lower equipment costs by using device server technology to replace dedicated PCs at each device. Device servers only cost a fraction of PCs. And, the cost calculation is not just the hardware alone, but the man-hours required to create software that would allow a PC-serial-port-based applications program to be converted into a program linking that information to the PC's network port. Device server technology resolves this issue by allowing the original applications software to be run on a networked PC and then use port redirector software to connect up to that device via the network. This enables the medical facility to transition from a PC at each device and software development required to network that data, to using only a couple of networked PCs doing the processing for all of the devices.

Additional Network Security

Of course, with the ability to network devices comes the risk of outsiders obtaining access to important and confidential information. Security can be realized through various encryption methods. 
There are two main types of encryption: asymmetric encryption (also known as public-key encryption) and symmetric encryption. There are many algorithms for encrypting data based on these types.
AES
AES (Advanced Encryption Standards) is a popular and powerful encryption standard that has not been broken. Select Lantronix device servers feature a NIST-certified implementation of AES as specified by the Federal Information Processing Specification (FIPS-197). This standard specifies Rijndael as a FIPS-approved symmetric encryption algorithm that may be used to protect sensitive information.  A common consideration for device networking devices is that they support AES and are validated against the standard to demonstrate that they properly implement the algorithm. It is important that a validation certificate is issued to the product’s vendor which states that the implementation has been tested. Lantronix offers several AES certified devices including the AES Certified SecureBox SDS1100 and the AES Certified SecureBox SDS2100.
Secure Shell Encryption
Secure Shell (SSH) is a program that provides strong authentication and secure communications over unsecured channels. It is used as a replacement for Telnet, rlogin, rsh, and rcp, to log into another computer over a network, to execute commands in a remote machine, and to move files from one machine to another. AES is one of the many encryption algorithms supported by SSH. Once a session key is established SSH uses AES to protect data in transit.
Both SSH and AES are extremely important to overall network security by maintaining strict authentication for protection against intruders as well as symmetric encryption to protect transmission of dangerous packets. AES certification is reliable and can be trusted to handle the highest network security issues.
WEP
Wired Equivalent Privacy (WEP) is a security protocol for wireless local area networks (WLANs) which are defined in the 802.11b standard. WEP is designed to provide the same level of security as that of a wired LAN, however LANs provide more security by their inherent physical structure that can be protected from unauthorized access. WLANs, which are over radio waves, do not have the same physical structure and therefore are more vulnerable to tampering. WEP provides security by encrypting data over radio waves so that it is protected as it is transmitted from one end point to another.  However, it has been found that WEP is not as secure as once believed. WEP is used at the data link and physical layers of the OSI model and does not offer end-to-end security.
WPA
Supported by many newer devices, Wi-Fi Protected Access (WPA) is a Wi-Fi standard that was designed to improve upon the security features of WEP. WPA technology works with existing Wi-Fi products that have been enabled with WEP, but WPA includes two improvements over WEP. The first is improved data encryption via the temporal key integrity protocol (TKIP), which scrambles keys using a hashing algorithm and adds an integrity-checking feature to ensure that keys haven’t been tampered with. The second is user authentication through the extensible authentication protocol (EAP). EAP is built on a secure public-key encryption system, ensuring that only authorized network users have access. EAP is generally missing from WEP, which regulates access to a wireless network based on the computer’s hardware-specific MAC Address. Since this information can be easily stolen, there is an inherent security risk in relying on WEP encryption alone. 

Incorporating Encryption with Device Servers

In the simplest connection scheme where two device servers are set up as a serial tunnel, no encryption application programming is required since both device servers can perform the encryption automatically. However, in the case where a host-based application is interacting with the serial device through its own network connection, modification of the application is required to support data encryption.

Applications Abound

While this paper provides a quick snapshot of device servers at work in a variety of applications, it should be noted that this is only a sampling of the many markets where these devices could be used. With the ever-increasing requirement to manage, monitor, diagnose and control many and different forms of equipment and as device server technology continues to evolve, the applications are literally only limited by the imagination.

Glossary of terms *

Serial server
traditionally, a unit used for connecting a modem to the network for shared access among users.
Terminal server
traditionally, a unit that connects asynchronous devices such as terminals, printers, hosts, and modems to a LAN or WAN.
Device server
a specialized network-based hardware device designed to perform a single or specialized set of functions with client access independent of any operating system or proprietary protocol.
Print server
a host device that connects and manages shared printers over a network.
Console server
software that allows the user to connect consoles from various equipment into the serial ports of a single device and gain access to these consoles from anywhere on the network.
Console manager
a unit or program that allows the user to remotely manage serial devices, including servers, switches, routers and telecom equipment.


Written by