- Rome, Lazio, Italy
Mobile ad hoc networks (MANETs) are characterized by their intrinsic capability to be set up without needing any kind of infrastructure, allowing a high degree of flexibility both at technological level and at application and service... more
Mobile ad hoc networks (MANETs) are characterized by their intrinsic capability to be set up without needing any kind of infrastructure, allowing a high degree of flexibility both at technological level and at application and service level. For this reason they are particularly useful in environment where no fixed network infrastructure is available. For example, they are well suitable for emergency application, when fixed telecommunication infrastructures, whereas present, can be seriously damaged or destroyed. Satellite networks also work without terrestrial infrastructure, excluding one gateway localized inside the footprint, and are easy to be set up too. For the same reasons also satellites can be fruitfully be utilized in case of emergency. Nevertheless, these two technologies are not in competition, as they might appear, but absolutely complementary. In fact, ad hoc mobile networks are characterized by very small terminals, low consumption, limited capacity per user terminals...
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ABSTRACT SPDY is a new application technology, introduced by Google, to accelerate Web transfers over common internet links. Most of the SPDY techniques (i.e. header compression, pushing and multiplexing) are usually included in satellite... more
ABSTRACT SPDY is a new application technology, introduced by Google, to accelerate Web transfers over common internet links. Most of the SPDY techniques (i.e. header compression, pushing and multiplexing) are usually included in satellite Performance Enhancing Proxies (PEPs) to optimize performance. Therefore, SPDY over satellite is expected to improve performance but without the need of any specific modification over the network. Proof of such an improvement is revolutionary for the role of satellite in the future Internet, since it could be considered as a transparent link, which does not need ad-hoc protocol adaptations. This paper addresses Web performance over satellite using the new SPDY protocol. Performance assessment relies on a satellite emulator that reproduces in software a DVB-RCS link while running real implementations of both TCP/IP stacks and SPDY.
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The rapid evolution of the Web imposes the need of enhancing the HTTP over satellite channels. To this aim, SPDY is a protocol engineered to reduce download times of content rich pages, as well as for managing links characterized by large... more
The rapid evolution of the Web imposes the need of enhancing the HTTP over satellite channels. To this aim, SPDY is a protocol engineered to reduce download times of content rich pages, as well as for managing links characterized by large Round Trip Times (RTTs) and high packet losses. With such features, it could be an efficient solution to cope with performance degradations of HTTP over satellite. In this perspective, this paper compares the behaviors of HTTP and SPDY over a DVB-RCS satellite link. To conduct a thorough set of tests over a realistic scenario, we used the Satellite Network Emulation Platform (SNEP). In addition, we evaluated how different Bandwidth on Demand (BoD) methods impact over the retrieval of a page. Results clearly indicate that SPDY could be an effective solution to deliver Web contents over satellites in a more �efficient manner.
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TCP Noordwijk has been designed and implemented to optimize short transfers (i.e. HTTP traffic) over satellite links, while assuring good performance for long transfers (e.g., FTP) as well. It was developed in the frame of an European... more
TCP Noordwijk has been designed and implemented to optimize short transfers (i.e. HTTP traffic) over satellite links, while assuring good performance for long transfers (e.g., FTP) as well. It was developed in the frame of an European Space Agency (ESA) project [†]. Its target scenario is a controlled communication environment adopting DVB-RCS standard between I-PEPs. A rich test campaign to
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To exchange medical data between two distant locations is of paramount importance in a significant number of scenarios (emergency, developing countries, home care, training, etc.). This paper presents performance evaluation, through... more
To exchange medical data between two distant locations is of paramount importance in a significant number of scenarios (emergency, developing countries, home care, training, etc.). This paper presents performance evaluation, through emulation and using real medical equipment, of a Telemedicine application including Electro-encephalographic (EEG) data, audio, video and text. All the application flows will be routed through an IP-based network
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ABSTRACT In satellite systems, notwithstanding recently launched systems have significantly increased bandwidth availability and improved cost effectiveness, the efficient resource management to achieve competitive final cost to the... more
ABSTRACT In satellite systems, notwithstanding recently launched systems have significantly increased bandwidth availability and improved cost effectiveness, the efficient resource management to achieve competitive final cost to the users, not renouncing to the right satisfaction in terms of quality of service, is of primary importance.
ABSTRACT TCP Noordwijk manages very efficiently Internet traffic when a satellite link is included in the path. The improvement of the bandwidth estimator can further increase performance, especially in presence of competing traffic using... more
ABSTRACT TCP Noordwijk manages very efficiently Internet traffic when a satellite link is included in the path. The improvement of the bandwidth estimator can further increase performance, especially in presence of competing traffic using other TCP protocols, and the exploitation of innovative service paradigms, first of all, cloud computing. In this respect, a meaningful increase of data transfers with different requirements in terms of size and interactivity will be experienced and large bulk data transfers can imply congestion on the bottleneck link of the core networks, impairing performance of real-time data transfers. This issue is further emphasized when a satellite link is included on the path, since resources are limited and the large latency affects congestion recovery mechanisms. Flow control differentiation capability can be the solution to exploit cloud computing efficiently. In this paper, we propose to manage flows priority at the transport layer introducing a proxy agent installed before each satellite terminal exploiting cloud computing service, which can use different transport protocols and parameters according to the flow priority. The proxy includes the new TCP Noordwijk+ (TCPN+), which allows establishing efficient transfer of low-priority bulk data along with efficient handling of interactive data, keeping a degree of friendliness with existing standard TCP connections. The results, outcome of Ns-2 simulation, confirm the efficiency of the proposed solution.
ABSTRACT An efficient resource allocation is of paramount importance to guarantee the best performance with a fair distribution of satellite capacity, even for Multi-beam High Throughput Satellites (HTS) platforms. These platforms are... more
ABSTRACT An efficient resource allocation is of paramount importance to guarantee the best performance with a fair distribution of satellite capacity, even for Multi-beam High Throughput Satellites (HTS) platforms. These platforms are recently gaining relevance for broadband Internet access and are nowadays able to provide xDSL like services. Although the available bandwidth for HTS is greater than previous platforms, it is still fundamental to use it wisely and avoiding abuses, which may jeopardize the service performance of the installed user-base. This paper focuses on the commercial system using the KA-SAT platform by Eutelsat, where a Deep Packet Inspection (DPI) solution is adopted to allow multi-dimensional per-user and per-application priority. Simulation and emulation tests have been executed to identify both the optimal DPI configuration and the amount of satellite capacity to procure in order to meet user requirements. Test achievements are then used to provide useful inputs for the real platform configuration in the frame of the Lift Off ESA project.
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ABSTRACT Cloud computing can significantly improve efficiency in Internet utilization and data management. Several cloud applications (file sharing, backup, data up/download etc.) imply transfers of large amount of data without real-time... more
ABSTRACT Cloud computing can significantly improve efficiency in Internet utilization and data management. Several cloud applications (file sharing, backup, data up/download etc.) imply transfers of large amount of data without real-time requirements. In several use-cases cloud-computing solutions reduce operational costs and guarantee target QoS. These solutions become critical when satellite systems are utilized, since resources are limited, network latency is huge and bandwidth costs are high. Using satellite capacity for cloud-computing bulk traffic, keeping acceptable performance of interactive applications, is very important and can limit the connectivity costs. This goal can be achieved installing in the Set Top Box (STB) a proxy agent, to differentiate traffic and assign bandwidth according to priority, leaving spare capacity to bulk cloud computing traffic. This aim is typically reached using a specific QoS architecture, adding functional blocks at network or lower layers. We propose to manage such a process at transport layer only. The endpoint proxy implements a new transport protocol called TCP Noordwijk+, introducing a flow control differentiation capability. The proxy includes TPCN+ which efficiently transfers low-priority bulk data and handles interactive data, keeping a high degree of friendliness. The outcomes of Ns-2 simulations confirm applicability and good performance of the proposed solution.
ABSTRACT DVB-S/S2 is used to provide multimedia broadcasting and unidirectional IP based services over satellite networks, while DVB-RCS enhances transmission in a bidirectional way, enabling transmission over the satellite return... more
ABSTRACT DVB-S/S2 is used to provide multimedia broadcasting and unidirectional IP based services over satellite networks, while DVB-RCS enhances transmission in a bidirectional way, enabling transmission over the satellite return channel. Streaming Encapsulation (GSE) protocols are defined to transport 'P datagrams over DVB. They provide several benefits over Multiprotocol Encapsulation (MPE), typically used in DVB for transporting 'P data. While the security mechanism defined within DVB-RCS standard supports MPE encapsulation, there is no identified security mechanism for both ULE and GSE protocols. This paper proposes an enhanced security framework for DVBRCS security specifications adopting ULE encapsulation to provide secure lightweight encapsulation.
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ABSTRACT SPDY is a recent Web technology aimed to drastically improve web page load time. Its application on the common terrestrial networks allows expected benefits through a set of methods: multiplexing and priority of webpage objects,... more
ABSTRACT SPDY is a recent Web technology aimed to drastically improve web page load time. Its application on the common terrestrial networks allows expected benefits through a set of methods: multiplexing and priority of webpage objects, header compression, pushing and encryption. Currently, a performance assessment of SPDY over satellite is not available. This paper provides an assessment of SPDY performance over satellite links compliant to DVB-RCS standard. Peculiar satellite physical characteristics (i.e. large latency) together with the variable access delay introduced by the DVB-RCS DAMA schemes constitute a challenging communication environment, so that SPDY efficiency shall be carefully verified in this context. Performance assessment relies on a satellite emulator that reproduces in software physical satellite impairments while running real implementations of both TCP/IP stacks and SPDY.
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... 3782, April 2004. [11] S. Floyd, “Issue of TCP with SACK”. Technical report, January 1996. [12] C. Roseti and E. Kristiansen, “TCP N: TCP-Based Transport Optimized for Web Traffic in Satellite Networks”. 26th International... more
... 3782, April 2004. [11] S. Floyd, “Issue of TCP with SACK”. Technical report, January 1996. [12] C. Roseti and E. Kristiansen, “TCP N: TCP-Based Transport Optimized for Web Traffic in Satellite Networks”. 26th International Communications ...
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ABSTRACT Satellite systems can be fruitfully utilized to provide connectivity to terrestrial sensor networks to exploit large-scale monitoring applications based on IP protocol. Sensor traffic patterns are very different from those... more
ABSTRACT Satellite systems can be fruitfully utilized to provide connectivity to terrestrial sensor networks to exploit large-scale monitoring applications based on IP protocol. Sensor traffic patterns are very different from those occurring with current Internet applications, so that performance evaluation requires some specific investigation with the aim to draw the main requirements to achieve target Quality of Service (QoS). This paper addresses a preliminary study of the sensor data transmission over satellites highlighting the main key factors to take care in the system configuration: experienced delays, resource utilization and overall throughput. Analysis relies on a Ns-2 based simulator, which includes a sensor data generator and implements a DVB-RCS-compliant network.
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ABSTRACT
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ABSTRACT The traditional modular OSI-layered architecture has served a major role in the development of a variety of protocols. However, as physical layer impairments become complex and time varying, a dynamic cross-layer design can... more
ABSTRACT The traditional modular OSI-layered architecture has served a major role in the development of a variety of protocols. However, as physical layer impairments become complex and time varying, a dynamic cross-layer design can enable better performance. A Cross-Layer Architecture (CLA) is proposed to improve performance of error-tolerant applications running over UDP-Lite. This approach to implementation introduces new challenges in protocol design, as well as in the area of security, where the study proposes a new method to enable IP security (IPsec) authentication and integrity services at the network layer. Target scenarios include satellite multicast for large-scale delivery of data and video content. In this scenario, CLA can mitigate the effects of physical layer impairments and high latency. Numerical analysis has shown that a link design employing header compression and cross-layer signalling may protect protocol headers and can reduce the probability of packet discard. To evaluate the feasibility of the CLA, these methods have been implemented as an extension to the IPsec protocol, named Cross-Layer IPsec (CL-IPsec). A satellite emulation platform was used to validate the implementation of CL-IPsec and to evaluate the overall performance improvement resulting from the proposed CLA. Copyright © 2010 John Wiley & Sons, Ltd.
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ABSTRACT he great diffusion of wireless portable and handheld devices, along with the growing availability of applications on the Internet, led to a significant increase in the demand of access. Users require to continue business or... more
ABSTRACT he great diffusion of wireless portable and handheld devices, along with the growing availability of applications on the Internet, led to a significant increase in the demand of access. Users require to continue business or private activities when moving, with performance at least comparable with that experienced over fixed networks. A very interesting scenario encompasses broadband and uninterrupted access over high-speed trains. Developments of new telecommunication standards as well as innovative network architectures give the potential to fully match the aforementioned requirements. Nevertheless, there is a significant number of issues, especially related to system integration, mobility management, and propagation channel conditions, that need a careful analysis with the aim to support the design of real systems. This paper deals with this challenging scenario proposing a satellite-based architecture in which DVB-S2 and DVB-RCS standards, MIPv6 at layer 3 (for handover management), and an enhanced TCP version at layer 4, named TCP Noordwijk, allow to achieve good performance. An NS-2 enhanced simulator has supported the whole analysis. Results show the effectiveness of the proposed scheme against different modulation and coding configurations and compared with a selected set of TCP-enhanced versions. Copyright © 2012 John Wiley & Sons, Ltd.