OnTime Networks has participated in the following list of papers:
Use of GigE Vision Ethernet Cameras for Flight Test Applications Without Data Loss
As Ethernet based networks have become the dominant choice for Flight Test Instrumentation (FTI) network applications, it is also clear that Ethernet based camera integration and applications have yet to become more wide spread for system level design and integration. A significant customer base utilizes either separate video compression systems or even just stand-a-lone gopro cameras for recording purposes in an unsynchronized ways. The use of uncompressed high definition (HD) video from GigE Vision Ethernet cameras for flight test applications is a significant issue in managing the large volumes of data produced by the cameras and forwarding them to any 1000BASE-T(x) switch port without packet loss and significant delays.
Of course an easy approach to overcome this issue would be to just increase the network bandwidth from 1000BASE-T(x) to 10GBASE-SR, but most FTI systems just moved to 1000BASE-T(x) in the past years and therefore changing the overall system hardware is cost prohibited. One concern has been the use of compression algorithms to reduce the required video bandwidth, with the negative side effect that the image quality reduces and end-to-end latency increases, which is not acceptable for some applications. Further, it is important that data from cameras is available to a number of different multicast consumers within the FTI network, for example workstations, recorders and telemetry systems. These video data stream also require synchronization so that they can be analyzed in post processing.
IEB2002 VoIP Drives Real-time Ethernet
The real time properties of traditional Ethernet are poor. The end-to-end latency through an Ethernet network based on thin Ethernet (coax – 10BASE-2) or hubs (10BASE or 100BASE) depends on the network load. The non-deterministic property of the Carrier Sense Multiple Access – Collision Detection (CSMA/CD) scheme has been the main argument against Ethernet as the communication solution for applications with real time requirements. However, this has changed significantly with the introduction of Ethernet switches together with the new priority features of Ethernet switches. Real time applications based on switched Ethernet can take advantage of this technology driven by the fast growing Voice Over IP (VOIP) business.
ISPCS2007 ISPCS2007 PTP Enabled Network For FTI
Large-scale data acquisition and recording systems have long sought to benefit from the bandwidth, scalability, and low-cost of Ethernet and Internet Protocol (IP). However, these systems’ requirement for reliable correlation of data with time is impeded by Ethernet’s inherently non-deterministic transit delay.
With the advent of Precision Time Protocol (PTP), these challenges can now be overcome by deploying synchronized data sources that timestamp data at the source. Furthermore, data producers and consumers constitute a multicast data distribution model, where a single data source is observable by any interested subscribers. This paper details our work for Boeing’s 787 which deployed these technologies to build an innovative system capable of providing gigabit data throughput with sub-microsecond synchronization.
ITC2013 PTPv1 and PTPv2 translation in FTI systems
A Flight Test Instrumentation (FTI) system may consist of equipment that either supports PTPv1 (IEEE 1588 Std 2002) or PTPv2 (IEEE 1588 Std 2008). The challenge in such time distributed system is the poor compatibility between the two PTP protocol versions. This paper describes how to combine the PTP versions in the same network with minimum or no manual configuration.
ETC2014 Ethernet packet filtering for FTI – part I
Today’s modern flight test systems are based to a large extent on Ethernet technologies. The never-ending demand for increased bandwidth and speed also raises the need for clever packet filtering solutions on the Ethernet switches. The challenge is to avoid network bottlenecks and to ensure that Ethernet end nodes are not overwhelmed with data not meant for the given node. This paper describes the different packet filtering methods and how these techniques can be optimized for Flight Test Instrumentation (FTI) use.
ITC2014 Ethernet packet filtering for FTI – part II
Network loads close to Ethernet wire speed and latency-sensitive data in a Flight Test Instrumentation (FTI) system, represent challenging requirements for FTI network equipment. Loss of data due to network congestion, overflow on the end nodes, as well as packet latency above a few hundred microseconds, can be critical during a flight test. To avoid these problems, several advanced packet filtering and network optimization functions are required in order to achieve the best possible performance and thus avoid loss of data.
This paper gives insight into how to properly engineer an Ethernet-based FTI network and how to use advanced Ethernet switch techniques such as Quality of Service (QoS) and rate shaping.
ETTC2015 Guaranteed end-to-end latency through Ethernet
Latency sensitive data in a Flight Test Instrumentation (FTI) system represents a challenging network requirement. Data meant for the telemetry link sent through an on-board Ethernet network might be sensitive for high network latency. Worst case latency through the on-board Ethernet network for such data might be as low as a few hundred microseconds. This challenge is solved by utilizing the Quality of Service (QoS) properties on Ethernet FTI switches. This paper describes how to use Ethernet layer 1, layer 2 or layer 3 QoS principles of a modern Ethernet FTI network.
ITC2015 Advanced Network Tap application for FTI
Digital data distribution systems are widely used in Aerospace and Defense products to allow devices to communicate with one another. In many cases, it is desirable to monitor the data traffic flowing between two points in a copper or fiber-based Operational or Onboard Network System (ONS) for Flight Test Instrumentation (FTI) purposes because these ONS systems may carry important data that can be used without duplicating/installing a specific FTI data acquisition system to receive this data. The two types of network taps that can be used are Inline Network Taps and network end-point taps. This paper examines the usage of Inline Network Taps for FTI applications and how they can support network access strategies and objectives. An Inline Network Tap is a hardware device that allows access to data flowing across a network. These devices are typically active/powered and have a number of ports: a first tap port, a second tap port, and one or more mirror ports.
An in-line network tap inserted between the first and second tap port passes all data traffic through unimpeded but also copies that same data to one or more mirror ports. Some Inline Network Tap devices may also pass packets when the tap is not powered or a malfunction is detected on the device via an integrated bypass function. If the Inline Network Tap device goes offline the unit automatically bypasses the tap connection and data traffic is directed through the bypass directly to network devices. This capability is crucial for inline usage on mission-critical network segments that cannot afford the risk of losing the network connection. An in-line network tap can either be based on copper or fiber technology and as a “filterable” network tap can also provide advanced packet filtering capabilities. These filterable network taps can selectively pass data, e.g., based on VLAN ID or other parameters, to a mirror port for deep analysis, monitoring and recording. Another advanced tap function that is presented in this paper is the support for inserting time stamps at the tap level in monitored packets which provides a reference time when the data content of a given packet was generated at a data source1. This capability is a significant feature for FTI applications as most ONS systems do not provide time-stamped data.
DATT2016 PTP profile for FTI
Time synchronization based on the Precision Time Protocol (PTP) according to the IEEE 1588 standard is a core building block for state-of-the-art high-performance Flight Test Instrumentation (FTI) systems. Two versions of the IEEE 1588 standard have been launched: version 1 according to IEEE 1588™ – 2002 and version 2 according to IEEE 1588™ – 2008. The FTI industry/community is using both versions of the standard and the IEEE 1588 standards define several PTP profiles for various time synchronization usages in different industries.
This paper describes how the PTP standard is being used in FTI applications, looks at the unique industry requirements, and also proposes a PTP profile definition for FTI applications, including special time synchronization parameters/properties taken from the iNET standardization.
ETC2016 PTP version 3 in FTI
Time synchronization based on the Precision Time Protocol (PTP) according to the IEEE 1588 standard is a core building block for state-of-the-art high-performance Flight Test Instrumentation (FTI) systems. Two versions of the IEEE 1588 standard have been launched: PTP version 1 according to IEEE 1588™ – 2002 and PTP version 2 according to IEEE 1588™ – 2008. Now a new IEEE 1588™ working group has been established with the goal to launch a new revision of the IEEE 1588™ standard; i.e. PTP version 3.
The FTI industry is using both PTP versions 1 and 2. The poor backward compatibility between PTP version 2 and 1 has been a big challenge for the FTI community. Backward compatibility with older PTP versions, new functions and to what extent PTP version 3 is relevant for the FTI industry are described and discussed in this paper.