Analysis of contact graph routing enhancements for DTN space communications

Bezirgiannidis, Nikolaos; Caini, C.; Tsaoussidis, Vassilis

doi:10.1002/sat.1138

Cited by 30 publications

(25 citation statements)

References 23 publications

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“…In fact, given that DTN protocols assumes no upper bound on the signal delay and no expectation of continuous connectivity, the opposite is more likely. However, this scheme might result convenient if there is a single node that injects most of the traffic [24] .…”

Section: All-contactsmentioning

confidence: 99%

“…Since this is not currently considered in CGR reference implementations, this Dijkstra modification will be suggested for future ION releases. Furthermore, to mimic the default ION stack configuration, DtnSim implementation does not affect BDT by local or remote buffer occupancy as discussed in [24] . Also, not-return-to-sender restriction is en- 5 DtnSim is a publicly available simulator developed at the UNC, based in Omnet ++ (C ++ ) and specialized in DTSNs.…”

Section: Simulation Analysismentioning

confidence: 99%

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On route table computation strategies in Delay-Tolerant Satellite Networks

et al. 2018

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a b s t r a c tDelay-Tolerant Networking (DTN) has been proposed for satellite networks with no expectation of continuous or instantaneous end-to-end connectivity, which are known as Delay-Tolerant Satellite Networks (DTSNs). Path computation over large and highly-dynamic yet predictable topologies of such networks requires complex algorithms such as Contact Graph Routing (CGR) to calculate route tables, which can become extremely large and limit forwarding performance if all possible routes are considered. In this work, we discuss these issues in the context of CGR and propose alternatives to the existing route computation scheme: first-ending, first-depleted, one-route , and per-neighbor strategies. Simulation results over realistic DTSN constellation scenarios show that network flow metrics and overall calculation effort can be significantly improved by adopting these novel route table computation strategies. .ar (J.A. Fraire).DTN can be precisely computed in advance based on orbital elements. Also, power-conserving spacecrafts may communicate on infrequent, fixed intervals established by configuration. In any case, forthcoming episodes of communications (a.k.a. contacts ) are typically scheduled weeks or months before they occur and can be imprinted in a contact plan . The resulting contact plan can be either distributed in advance to DTN nodes, or used by a centralized node (i.e., mission control) to execute route determination procedures.A DTN paradigm can indeed be used to forward data on near-Earth satellite networks with sporadic satellite-to-satellite and satellite-to-ground communication opportunities. If so, we define them as Delay-Tolerant Satellite Networks (DTSNs). DTSNs differ from other space DTNs in the size of the topology and the speed at which it changes. In particular, interplanetary networks are rather scarce in terms of spacecrafts as a few rovers on a remote planet plus some orbiters are typically assumed in the literature [7] . While this density of deep-space nodes is unlikely to change in the near future, DTSNs topologies are expected to be promptly based on dozens or even hundreds of satellites [1] . Furthermore, while in interplanetary DTNs the topological changes are dictated by planetary dynamics, communication opportunities in DTSNs typically occur much more frequently between satellites in Low-Earth Orbit (LEO). As a result, the scalability limits of current DTN protocols and algorithms are likely to be met sooner in DTSN than in deep-space applications. Thus, DTSNs become an immediate object of study for evaluating efficient routing strategies which will also, in the long term, be valuable in the interplanetary domain.

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Section: All-contactsmentioning

confidence: 99%

Section: Simulation Analysismentioning

confidence: 99%

On route table computation strategies in Delay-Tolerant Satellite Networks

et al. 2018

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“…Perhaps one of the most established methods of routing in space networks, originally designed for deep-space networks, is contact graph routing (CGR) [21], which in its original form follows much of the literature in using Dijkstra's algorithm to identify the next hop node along a journey. Extensions include the consideration of an earliest arrival time objective [22], multiple destinations [23], timeliness effects of potential data-delivery failure due to lossy signal [24], effects on delay from downstream buffer queues [25,26], and an approach to overcome the effects of high-priority data preventing transmission of bulk packets during a scheduled contact [27,28]. Although CGR has strengths in terms of development and deployment, the journey cost functions, mission objectives, and resource considerations could be considered lacking in generality.…”

Section: Related Workmentioning

confidence: 99%

Resource-Considerate Data Routing Through Satellite Networks

Lowe

Macdonald

2017

Journal of Aerospace Information Systems

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In many envisaged satellite-based networks, such as constellations or federations, there often exists a desire to reduce data latency, increase delivered data volume, or simply exploit unused resources. A strategy is presented that achieves efficient routing of data, in a store-carry-forward fashion, through satellite networks that exhibit delay-and disruption-tolerant network characteristics. This network-layer protocol, termed Spae, exploits information about the schedule of future contacts between network nodes, because satellite motion is deterministic, along with the capacity of these contacts to route data in such a way as to avoid significant overcommitment of data along a resourcelimited journey. Results from simulations of a federated satellite system indicate consistent benefit in terms of network performance over other, less-sophisticated, conventional methods, and comparable performance to a packet-optimal, full-knowledge approach.

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“…It actually comprises a family of algorithms 13 that have been proposed since its first appearance; variations include incorporation of Dijkstra algorithm, 14 source-routing-like CGR that includes the encoded path in the message, 15 incorporation of queue length information in delivery delay estimations, 16 and CGR with proactive overbooking management when high priority bundles (the protocol data units of BP) are forwarded on a contact that is already fully subscribed by lower priority bundles. 17 Apart from routing decisions, contact plan information can be used in different perspectives. At the CL for example, LTP enables efficient operation over frequently disrupted links by suspending its retransmission timers whenever a scheduled link outage occurs.…”

Section: Background and Related Workmentioning

confidence: 99%

“…The proposed end-to-end retransmission framework was deployed as part of version 3.2.2 of ION-DTN implementation, which includes the RFC 5050 BP implementation 3 and the CGR-ETO variant of the CGR algorithm. 17 To enable the required interlayer communication between DTPC and BP/CGR, 2 modifications on the overall operation of BP/CGR were implemented.…”

Section: Bp/cgr Modificationsmentioning

confidence: 99%

An adaptive end‐to‐end RTO calculation framework for DTNs with scheduled connectivity

Diamantopoulos

Bezirgiannidis

Tsaoussidis

2017

Satell Commun Network

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Summary In this work, we propose an end‐to‐end retransmission framework for dynamically calculating efficient retransmission time‐out intervals in delay‐tolerant networks (DTNs) with scheduled connectivity. The proposed framework combines deterministic and statistical information about the network state to calculate worst‐case estimates about the expected round trip times. Such information includes connectivity schedules, convergence layer protocols specifics, communication link characteristics, and network statistics about the maximum expected packet error rates and storage congestion. We detail the implementation of the proposed framework within the end‐to‐end application data conditioning layer proposed for the DTN architecture, realized by the Delay‐Tolerant Payload Conditioning protocol, as part of the Interplanetary Overlay Network–DTN reference implementation, and evaluate its performance in a complex deep‐space emulation scenario in our DTN testbed. Our results show that our approach achieves great accuracy in round‐trip time estimations and, therefore, faster retransmissions of lost data, in comparison to the statically configured retransmission mechanism of the original Delay‐Tolerant Payload Conditioning protocol. As a result, in‐order data reception rate and storage requirements on the receiver side are significantly improved, at minimum or even zero extra cost in transmission overhead due to duplicate transmissions.

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Analysis of contact graph routing enhancements for DTN space communications

Cited by 30 publications

References 23 publications

On route table computation strategies in Delay-Tolerant Satellite Networks

On route table computation strategies in Delay-Tolerant Satellite Networks

Resource-Considerate Data Routing Through Satellite Networks

An adaptive end‐to‐end RTO calculation framework for DTNs with scheduled connectivity

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