Development and evaluation of packet video schemes

1998

2009 First International Conference on Advances in Satellite and Space Communications, 2009

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions. This activity was part of a larger NASA space DTN development program to mature DTN to flight readiness for a wide variety of mission types by the end of 2011. This paper describes the DTN protocols, the flight demo implementation, validation metrics which were created for the experiment, and validation results.

End-to-End Quality of Service Over Heterogeneous Networks, 2008

The rapidly growing Internet architecture is causing most recent computer applications to integrate a more or less important part of distributed functionalitiessuch as transport layer services, transport protocols and other services-that need to meet user's necessities in terms of functionalities and Quality of Service (QoS) requirements. Emulation platforms are a classical way for protocol and applicative experiments to check if user and QoS requirements are met. They complement the simulation and real network experiments, since they enable to use real implementation of protocols or applications without having a real network deployed for the experiments. This chapter presents the emulation approach in the context of networking experimentation: First, the different possible utilisations of dynamic emulation in the context of networking and protocol engineering are presented. Then, requirements for a general network emulation framework are proposed. Furthermore, different network emulation platforms and tools implementing the general framework are exposed; we describe how to use them in the context of protocol engineering and discuss their advantages and disadvantages. Finally, the emulation of wireless systems is challenging, due to many parameters affecting the resulting behaviour of the channel. Satellite emulation, a subset of wireless emulation, has unique characteristics concerning the access to the resource that combines static and dynamic assignment. As an example, the emulation of a QoS-oriented satellite system is detailed in a final section.

SpaceOps 2008 Conference, 2008

The Interplanetary Network Directorate (IND) of NASA's Deep Space Mission System (DSMS) program identified several trends in future space exploration missions that pose new challenges for multi-mission telecommunications and navigation systems, such as: increasing number of communication links and relays, 1000-fold increase in data volumes, and growing complexity in end-to-end communications (including disruption of links). Automation and demand access are among the proposed concepts/technologies to meet these challenges. Currently, most interplanetary telecommunication systems require human intervention for command and control. However, considering the range from near Earth to deep space missions, combined with the increase in the number of nodes and advancements in processing capabilities, the benefits from communication autonomy will be immense. Likewise, greater mission science autonomy brings the need for unscheduled, unpredictable communication and network routing. While the terrestrial Internet protocols are highly developed their suitability for space exploration has been questioned. JPL has developed the Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) tool to help characterize network designs and protocols. The results will allow future mission planners to better understand the trade offs of communication protocols. This paper discusses various issues with interplanetary network and simulation results of interplanetary networking protocols.

Automotive electronics is a rapidly expanding area with an increasing number of driver assist and infotainment devices becoming standard in new vehicles. A review of the current landscape of networking standards within vehicles reveals a fragmented and proprietary state of affairs with several "standards" dominating the sphere including MOST, CAN and LVDS all of which are in current use by various vehicle manufacturers. Due to the costly nature of equipment and testing apparatus for these standards, there is a general desire within the automotive industry to use the 802.3 Ethernet standards for all in-vehicle communication between devices. This paper presents an overview of an ns-3 based simulation environment which is the initial step in an ongoing research effort to design cost effective, flexible and deterministic in-vehicle networks suitable for use in the next generation of vehicles, particularly for use by driver assist applications.

The ever growing use of Internet applications (e.g., email, file transfer, remote access and web browsing) is causing progressive congestion of telecommunication networks.

The rapidly growing Internet architecture is causing most recent computer applications to integrate a more or less important part of distributed functionalitiessuch as transport layer services, transport protocols and other services-that need to meet user's necessities in terms of functionalities and Quality of Service (QoS) requirements. Emulation platforms are a classical way for protocol and applicative experiments to check if user and QoS requirements are met. They complement the simulation and real network experiments, since they enable to use real implementation of protocols or applications without having a real network deployed for the experiments. This chapter presents the emulation approach in the context of networking experimentation: First, the different possible utilisations of dynamic emulation in the context of networking and protocol engineering are presented. Then, requirements for a general network emulation framework are proposed. Furthermore, different network emulation platforms and tools implementing the general framework are exposed; we describe how to use them in the context of protocol engineering and discuss their advantages and disadvantages. Finally, the emulation of wireless systems is challenging, due to many parameters affecting the resulting behaviour of the channel. Satellite emulation, a subset of wireless emulation, has unique characteristics concerning the access to the resource that combines static and dynamic assignment. As an example, the emulation of a QoS-oriented satellite system is detailed in a final section.

IEEE Communications Magazine, 2003

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)

The throughput results for file transfers using file sizes ranging from 1 Kbytes through 1 Mbytes using both the standard TCP/IP and SCPS protocol stacks over a PPP link are reported. Channel properties were simulated using a space channel simulator with a range of balanced and unbalanced link speeds and channel error rates. The throughput results will show the effects of link configuration and channel error rate on file transfer time. The host computer configuration options for the protocols are factored into the comparison. The throughput reporting shows the effects of header compression and selection of congestion algorithm upon the results. The TCP/IP ftp and SCPS-FP using VJ congestion control algorithm results give similar results and better results than SCPS-FP with the Vegas congestion control algorithm in these experiments. No noticeable delay effects were noted with links delays corresponding to GEO orbits with file transfers of 1 Mbytes. TABLE OF CONTENTS 1. INTRODUCTION 2. METHODS AND PROCEDURES 3. RESULTS AND DISCUSSIONS 4. CONCLUSIONS 5. ACKNOWLEDGEMENTS 6. REFERENCES We have developed a Space-to-Ground Link Simulator (SGLS) to provide the simulation capabilities to test both protocol suites ([2], [3], and [4]). During the testing, we discovered that the protocol suites have a number of options that affect the overall protocol performance more greatly than others. This report discusses the experiments performed to map out how the options affect the overall performance from the user's point of view. When possible, option performance on both suites of protocols will be compared in a fair a manner as possible.