2,225 research outputs found
A methodological approach to BISDN signalling performance
Sophisticated signalling protocols are required to properly handle the complex multimedia, multiparty services supported by the forthcoming BISDN. The implementation feasibility of these protocols should be evaluated during their design phase, so that possible performance bottlenecks are identified and removed. In this paper we present a methodology for evaluating the performance of BISDN signalling systems under design. New performance parameters are introduced and their network-dependent values are extracted through a message flow model which has the capability to describe the impact of call and bearer control separation on the signalling performance. Signalling protocols are modelled through a modular decomposition of the seven OSI layers including the service user to three submodels. The workload model is user descriptive in the sense that it does not approximate the direct input traffic required for evaluating the performance of a layer protocol; instead, through a multi-level approach, it describes the actual implications of user signalling activity for the general signalling traffic. The signalling protocol model is derived from the global functional model of the signalling protocols and information flows using a network of queues incorporating synchronization and dependency functions. The same queueing approach is followed for the signalling transfer network which is used to define processing speed and signalling bandwidth requirements and to identify possible performance bottlenecks stemming from the realization of the related protocols
Applications of satellite technology to broadband ISDN networks
Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization
Long-Range Communications in Unlicensed Bands: the Rising Stars in the IoT and Smart City Scenarios
Connectivity is probably the most basic building block of the Internet of
Things (IoT) paradigm. Up to know, the two main approaches to provide data
access to the \emph{things} have been based either on multi-hop mesh networks
using short-range communication technologies in the unlicensed spectrum, or on
long-range, legacy cellular technologies, mainly 2G/GSM, operating in the
corresponding licensed frequency bands. Recently, these reference models have
been challenged by a new type of wireless connectivity, characterized by
low-rate, long-range transmission technologies in the unlicensed sub-GHz
frequency bands, used to realize access networks with star topology which are
referred to a \emph{Low-Power Wide Area Networks} (LPWANs). In this paper, we
introduce this new approach to provide connectivity in the IoT scenario,
discussing its advantages over the established paradigms in terms of
efficiency, effectiveness, and architectural design, in particular for the
typical Smart Cities applications
NASA and the challenge of ISDN: The role of satellites in an ISDN world
To understand what role satellites may play in Integrated Services Digital Network (ISDN), it is necessary to understand the concept of ISDN, including key organizations involved, the current status of key standards recommendations, and domestic and international progress implementation of ISDN. Each of these areas are explained. A summary of the technical performance criteria for ISDN, current standards for satellites in ISDN, key players in the ISDN environment, and what steps can be taken to encourage application of satellites in ISDN are also covered
Application of Asynchronous Transfer Mode (Atm) technology to Picture Archiving and Communication Systems (Pacs): A survey
Broadband Integrated Services Digital Network (R-ISDN) provides a range of narrowband and broad-band services for voice, video, and multimedia. Asynchronous Transfer Mode (ATM) has been selected by the standards bodies as the transfer mode for implementing B-ISDN; The ability to digitize images has lead to the prospect of reducing the physical space requirements, material costs, and manual labor of traditional film handling tasks in hospitals. The system which handles the acquisition, storage, and transmission of medical images is called a Picture Archiving and Communication System (PACS). The transmission system will directly impact the speed of image transfer. Today the most common transmission means used by acquisition and display station products is Ethernet. However, when considering network media, it is important to consider what the long term needs will be. Although ATM is a new standard, it is showing signs of becoming the next logical step to meet the needs of high speed networks; This thesis is a survey on ATM, and PACS. All the concepts involved in developing a PACS are presented in an orderly manner. It presents the recent developments in ATM, its applicability to PACS and the issues to be resolved for realising an ATM-based complete PACS. This work will be useful in providing the latest information, for any future research on ATM-based networks, and PACS
Benchmarking and viability assessment of optical packet switching for metro networks
Optical packet switching (OPS) has been proposed as a strong candidate for future metro networks. This paper assesses the viability of an OPS-based ring architecture as proposed within the research project DAVID (Data And Voice Integration on DWDM), funded by the European Commission through the Information Society Technologies (IST) framework. Its feasibility is discussed from a physical-layer point of view, and its limitations in size are explored. Through dimensioning studies, we show that the proposed OPS architecture is competitive with respect to alternative metropolitan area network (MAN) approaches, including synchronous digital hierarchy, resilient packet rings (RPR), and star-based Ethernet. Finally, the proposed OPS architectures are discussed from a logical performance point of view, and a high-quality scheduling algorithm to control the packet-switching operations in the rings is explained
D2D-Based Grouped Random Access to Mitigate Mobile Access Congestion in 5G Sensor Networks
The Fifth Generation (5G) wireless service of sensor networks involves
significant challenges when dealing with the coordination of ever-increasing
number of devices accessing shared resources. This has drawn major interest
from the research community as many existing works focus on the radio access
network congestion control to efficiently manage resources in the context of
device-to-device (D2D) interaction in huge sensor networks. In this context,
this paper pioneers a study on the impact of D2D link reliability in
group-assisted random access protocols, by shedding the light on beneficial
performance and potential limitations of approaches of this kind against
tunable parameters such as group size, number of sensors and reliability of D2D
links. Additionally, we leverage on the association with a Geolocation Database
(GDB) capability to assist the grouping decisions by drawing parallels with
recent regulatory-driven initiatives around GDBs and arguing benefits of the
suggested proposal. Finally, the proposed method is approved to significantly
reduce the delay over random access channels, by means of an exhaustive
simulation campaign.Comment: First submission to IEEE Communications Magazine on Oct.28.2017.
Accepted on Aug.18.2019. This is the camera-ready versio
Cell Utilization Efficiency of Internet Protocol Traffic over Asynchronous Transfer Mode Networks
In the near future, large computer networks will be connection oriented,
with at least the data link connectivity being provided by the Asynchronous
Transfer Mode.
(ATM) networks. However, these networks may have to
communicate with the existing network which predominantly use Internet
Protocol (IP). Running Internet Protocol over Asynchronous Transfer Mode
Network has been a contentious issue due to the inefficient segmentation of
Internet Protocol packets into Asynchronous Transfer Mode (ATM) cells. In
this thesis, the current protocols and standards pertaining to Internet
Protocol over Asynchronous Transfer Mode are discussed and overheads
involved in placing Internet Protocol packets into Asynchronous Transfer
Mode cells, taking Logical Link Control/Sub Network Attachment Point
Encapsulation into consideration, are analysed to find out the cell utilization
of Asynchronous Transfer Mode cell in carrying the Internet Protocol
packets. The Wide Area Network (WAN) oriented traffic for our analysis is
collected from the Internet Traffic Archive. Analysis of the trace results show that the Asynchronous Transfer Mode
cell utilisation is better in carrying the user information if the Internet
Protocol packet are sizes larger. It is observed that ranges of Internet
Protocol packets require similar number of Asynchronous Transfer Mode
cells. At small values of Internet Protocol packets, the efficiency of
Asynchronous Transfer Mode cell in carrying the user information is
significantly low due to the Logical Link Control Encapsulation, padding and
the trailer overheads. The Asynchronous Transfer Mode Cell utilization is
better in Virtual Circuit (VC) based multiplexing, saving 8 bytes of
encapsulation for each packet, thus improving the Asynchronous Transfer
Mode (ATM) cell utilization marginally. It is seen that 80% of the Internet
Protocol packet length varies from 54 to 200 bytes for which cell utilisation
varies from 50%-to 82%. However, the average cell utilisation is 84% in the
20,000 packets observed since 20% of the Internet Protocol packet length is
greater than 1000 bytes
Recent trends in IP/NGEO satellite communication systems: transport, routing, and mobility management concerns
科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究
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