Networking Devices can communicate with each other and with central or back offices via many communication media, such as dial-up or cellular modems, private radio networks, leased lines, satellite, Wireless LAN or wired LANs. Most networks have some form of security to restrict access. The two most common forms of network security are firewalls and network address translators (NATs). These security measures are very effective at keeping unauthorized users out of the network. However, they also keep out authorized users and legitimate clients who try to gain access from outside of the network or subnet.
The Problem of Dynamic and non-Public IP Addresses
IP-based networks use IP addresses to establish sessions. In order to communicate over the Internet a system must have an IP address. There are several categories of IP addresses that may be assigned to a system: fixed or dynamic IP addresses, false IP (or non-public IP) addresses, or real (public) IP addresses. Nodes that are assigned false IP addresses may only act as clients on the network. They cannot open passive, listening sockets and act as a server. Therefore, networked systems cannot initiate a connection to these nodes; they may only be replied to. As such, these nodes cannot host a Web server, which is an important component in remote configuration, remote monitoring and remote control of networked devices. Server systems that have a dynamic and/or false IP address are problematic because (a) in the case of dynamic IP address, the client systems do not know what IP address to use to access them and (b) they cannot approach them in the case of false IP address. A Web browser must know the Web server's name or IP address in order to access it.
The Solution: Connect One's Device Connectivity Server
Connect One's Device Connectivity Server™ (DCS) is a combination Web server, registration server, and proxy server. It is a tool for system integrators and device operators to overcome the aforementioned drawbacks of accessing devices located behind NATs and firewalls. It allows devices with dynamic and/or illegal IP addresses to act as servers, regardless of the IP address they are assigned. It also provides a simple Application Programming Interface (API) for a remote application so that it can connect to devices in the field.
The DCS solution is based on two components: an agent running on the iChip™ (device side) and the DCS server application running on a dedicated, networked PC running Windows. The PC is permanently connected to the Internet via a fixed IP address, preferably with a DNS-registered host name. Since the DCS acts as a proxy, its upstream and downstream bandwidths should be balanced. The PC also hosts a Windows Access database system and a Web server.
The Device Connectivity Server's Web site is the front-end interface for managing all remote Internet-enabled devices. Information may be obtained from the DCS by surfing to the DCS?s Web site with a standard browser or by querying the DCS over a TCP/IP socket using Connect One's API (distributed as an Active-X).
For more information about Connect One's Device Connectivity Server, please read the technology brief.
