C²I² Press Release
C²I² Systems, leading developer and distributor of real-time, mission-critical networks to the South African National Defence Force and key industrial sectors, has developed an extended profile protocol called Network Time Services (NTS) to synchronise systems and timestamp messages.
Implementation of NTS will circumvent "jitter" and latency, which can lead to instability in distributed control algorithms.
According to C²I² Systems’ managing director, Richard Young, networked systems can still suffer from transfer latency and jitter despite considerable raw performance availability at the lower layers of the LAN profile.
However, he said the data repetition rates required by the collaborative distributed algorithms can be sufficient if accurate timing of the data samples can be recovered.
Real-time systems therefore require services from the network which circumvent the problems associated with latency and jitter, he said.
Timestamping of the data by the processor, using accurate network time derived from Network Time Protocol (NTP), allows a consumer to reconstruct critical timing information by determining the age of the data.
"NTP implements timing mechanisms between all participating sub-systems over the network. The protocol does not rely on the accuracy of the clock of a single peer but rather attempts to find the most accurate time source available to it from a hierarchical time server."
"Each node maintains a local clock to provide time values and to synchronise with all other clocks on the network. NTP provides basic functionality, such as synchronisation and timestamping, to NTS, which in turn provides user-level time services to the application."
According to Young, NTS allows a user to obtain the current clock and an indication of the accuracy and quality of the value.
"NTS can provide synchronisation services, both with respect to calendar time (that is absolute time) as well as relative time between distributed clocks.
"For many distributed applications, only relative time synchronisation is required. For certain applications, such as synchronisation of remote encryption devices, calendar time synchronisation is required," said Young.
C²I² Systems has also introduced BITS, the Built-in Test Services which, in conjunction with its Network Management System (NMS), provides real-time monitoring (integrity checking) and dynamic configuration control of the entire networked system, event and alarm reporting, statistical performance measurement, comprehensive diagnostic facilities, computer-assisted trouble shooting and maintenance.
Young says network management consists of two levels: the lower level implementing network management functions and the higher level implementing system monitoring.
"The managing application on the lower level manages managed objects by means of management agents. It derives data from the managed objects by means of a LAN-based network management protocol (that is SNMP) and stores this data in a Management Information Base (MIB).
"The data in the MIB is then processed to provide user level management information by means of the NMS man-machine interface."
"The management agent performs management operations on managed objects and produces notification of events on behalf of managed objects within the node in which it resides. It acts as an intermediary between the managing application and the entities which have managed objects within the node," he says.
The NMS consists of hardware and computer software components. The hardware component provides physical connectivity to the LAN as well as providing a processing platform for the NMS software component.
According to Young, the NMS provides higher level system health monitoring and provides online monitoring and control of the entire network system, reconfiguration management and high-level diagnostics facilities.
"For example, for maintenance crew manned systems, on a ship or large industrial site – say a power station or steel production plant, the NMS provides extensive man-machine interface functionality," he says.
"It supports an operator’s console which provides graphics-based, diagrammatic visualisation of the system and its network components. The display provides high resolution colour graphics and interacts with pointing devices such as mouse, trackball or joystick."