Showing papers on "Communications protocol published in 1998"

GloMoSim: a library for parallel simulation of large-scale wireless networks

Abstract: A number of library based parallel and sequential network simulators have been designed. The paper describes a library, called GloMoSim (Global Mobile system Simulator), for parallel simulation of wireless networks. GloMoSim has been designed to be extensible and composable: the communication protocol stack for wireless networks is divided into a set of layers, each with its own API. Models of protocols at one layer interact with those at a lower (or higher) layer only via these APIs. The modular implementation enables consistent comparison of multiple protocols at a given layer. The parallel implementation of GloMoSim can be executed using a variety of conservative synchronization protocols, which include the null message and conditional event algorithms. The paper describes the GloMoSim library, addresses a number of issues relevant to its parallelization, and presents a set of experimental results on the IBM 9076 SP, a distributed memory multicomputer. These experiments use models constructed from the library modules.

Minimum energy mobile wireless networks

Abstract: We describe a distributed position-based network protocol optimized for minimum energy consumption in mobile wireless networks that support peer-to-peer communications. Given any number of randomly deployed nodes over an area, we show that a simple local optimization scheme executed at each node guarantees strong connectivity of the entire network and attains the global minimum energy solution for the stationary case. Due to its localized nature, this protocol proves to be self-reconfiguring and stays close to the minimum energy solution when applied to the case of mobile nodes. Our simulations verify its performance.

ANTS: a toolkit for building and dynamically deploying network protocols

Abstract: The authors present a novel approach to building and deploying network protocols. The approach is based on mobile code, demand loading, and caching techniques. The architecture of the system allows new protocols to be dynamically deployed at both routers and end systems, without the need for coordination and without unwanted interaction between co-existing protocols. They describe the architecture and its realization in a prototype implementation. To demonstrate how to exploit the architecture, they present two simple protocols that operate within the prototype to introduce multicast and mobility services into a network that initially lacks them.

Intelligent multi-access system

Abstract: A multi-access remote system having a security surveillance area, a plurality of end user locations, and a communications network such that one or more of the end user locations can establish a connection with the security surveillance area, and vice versa, using a communications protocol via the communications network The security surveillance area is comprised of a local computer system, a camera with motion sensor, and a network interface When the motion sensor detects an obstruction the camera starts recording and the local computer system notifies a remote individual of the alarm via a communications device, such as a beeper, telephone, or e-mail Using an end user location, having a remote computer system, a network interface, and one or more communications devices, the remote individual can logon to the local computer system via the communications network and obtain additional information, control the video camera remotely, or view video images Access to the security surveillance area, control of the video camera, and viewing of the video data is accomplished advantageously over the Internet with application specific browser software, plugins, APIs, and other protocols

Pots/packet bridge

Abstract: A system and method for bridging the POTS network and a packet network, such as the Internet, uses a set of access objects that provide the interfacing and functionality for exchanging address and payload information with the packet network, and for exchanging payload information with the payload subnetwork and signaling information with the signaling subnetwork of the POTS network. The system includes a communications management object that coordinates the transfer of information between the POTS network and the packet network; a payload object that transfers payload information between the system and the payload subnetwork of the first communications network; a signaling object that transfers signaling information between the system and the signaling subnetwork of the first communications network in accordance with a signaling protocol associated with the signaling subnetwork; and a packet object that transfers payload and address information between the system and the second communications network in accordance with a communications protocol associated with the second communications network. An alternative embodiment uses a plurality of payload, signaling and packet objects to provide a scalable system.

Remote access to electronic meters using a tcp/ip protocol suite

Abstract: An electronic meter incorporates a TCP/IP protocol suite and an HTTP server to provide two-way access to the meter data. Alternatively, the TCP/IP protocol suite may be incorporated into a gateway serving multiple meters connected through a power line or wireless two-way network. The gateway may incorporate an HTTP server for accessing data from multiple meters and for transmission of data to individual meters. Other aspects of the disclosed system include the use of a common gateway interface for remote access to meter data and to set meter parameters using HTML forms in HTTP browsers; remote reading and setting of multiple meter parameters using a TCP/IP protocol suite; a TCP/IP protocol suite implemented in designated nodes in a CEBus LAN with remote access through TCP/IP to routers and brouters and to individual meters on the LAN; and an SLIP-PPP enabled gateway for remote TCP/IP access through a serial interface to a single or multiple meter parameters.

System and method for accessing information from a remote device and providing the information to a client workstation

Abstract: A micro-server adapted to be embedded into a piece of industrial machinery, an automobile, a consumer product, and the like, for publishing information, possibly in the form of web pages, about the device into which the micro-server is embedded or with which it is associated and/or for controlling a micro-server equipped device from a possibly remote client. The information may be published such that it is accessible using a standard web-browser. Other suitable protocols could also be used. The micro-server is capable of interfacing with a device to access information from the device, such as control or maintenance information. The micro-server can then organize and format that information compatible with a communication protocol in preparation for publishing the information. The micro-server conveniently abstracts from the first device the details of the communication protocol used to publish the information.

Defibrillator with wireless communications

Abstract: A defibrillator having infrared communication capability is provided. The wireless communications capability is implemented using infrared light or RF communications and standardized communications protocols such as the IrDA protocol to allow for ready communication between defibrillators such as during handoffs of patient along the Chain of Survival. The wireless communications network also allows for communications between a defibrillator and a host computer such as a palmtop for incident report generation after each handoff. Another embodiment of the present invention provides for a defibrillator having an infrared mode switch to allow for restricted access to advanced cardiac life support (ACLS) features of the defibrillator. A further embodiment of the present invention provides for a defibrillator having a remote training mode that is implemented via wireless communications. Another embodiment of the present invention provides for a defibrillator test system that is implemented via wireless communications. A further embodiment of the present invention provides for a live ECG telemetry data link using the wireless communications system.

Method and system for controlling and communicating with machines using multiple communication formats

Abstract: A method and system which allows a remote monitoring and diagnostic computer or system to communicate using different communication protocols which are stored within a data base. After a communication is received, it is analyzed to determine if there is a protocol identifier. If the protocol identifier exists, a data base is searched to determine the format of the header of the communication. Once the format of the header is determined, the header of the received communication is read to determine the information contained therein. This information is utilized to determine the actual format of the data which follows. If the protocol identifier does not exist, the received communication is examined to determine if it is in a format which matches one of a plurality of previously defined format. Critical fields are defined which must have certain values and if the received communication matches these critical values, the record in a communication protocol data base matching the critical values will be utilized in order to determine the protocol of the data which has been received in the communication. The machine to which the remote monitoring and diagnostic system is connected is a business office device such as a copier, printer, or facsimile machine, a digital camera, or another type of device.

A comparison of reliable multicast protocols

Abstract: We analyze the maximum throughput that known classes of reliable multicast transport protocols can attain. A new taxonomy of reliable multicast transport protocols is introduced based on the premise that the mechanisms used to release data at the source after correct delivery should be decoupled from the mechanisms used to pace the transmission of data and to effect error recovery. Receiver-initiated protocols, which are based entirely on negative acknowledgments (NAKS) sent from the receivers to the sender, have been proposed to avoid the implosion of acknowledgements (ACKS) to the source. However, these protocols are shown to require infinite buffers in order to prevent deadlocks. Two other solutions to the ACK-implosion problem are tree-based protocols and ring-based protocols. The first organize the receivers in a tree and send ACKS along the tree; the latter send ACKS to the sender along a ring of receivers. These two classes of protocols are shown to operate correctly with finite buffers. It is shown that tree-based protocols constitute the most scalable class of all reliable multicast protocols proposed to date.

Data transmission over a power line communications system

Abstract: A power line communications system comprises a power line (120) for distributing electricity to a plurality of premises (S1, S2...) and communication stations (TRX) coupled to the power line at the premises. Data is transmitted to/from stations over the power line using a packet data communications protocol. Apparatus at premises can convert signals between a first protocol, used on the power line, and a second protocol e.g. Ethernet for transferring data to a communications station.

User-level network interface protocols

Abstract: Modern high speed local area networks offer great potential for communication intensive applications, but their performance is limited by the use of traditional communication protocols, such as TCP/IP. In most cases, these protocols require that all network access be through the operating system, which adds significant overhead to both the transmission path (typically a system call and data copy) and the receive path (typically an interrupt, a system call, and a data copy). To address this performance problem, several user level communication architectures have been developed that remove the operating system from the critical communication path. The article describes six important issues to consider in designing communication protocols for user level architectures. The issues discussed focus on the performance and semantics of a communication system. These issues include data transfer, address translation, protection, and control transfer mechanisms, as well as the issues of reliability and multicast. To provide a basis for analyzing these issues, the authors present a simple network interface protocol for Myricom's Myrinet network, which has a programmable network interface. Researchers can thus explore many protocol design options, and several groups have designed communication systems for Myrinet. The authors refer to 11 such systems, all of which differ significantly in how they resolve these design issues but all of which aim for high performance and provide a lean, low level, and more or less generic communication facility.

System and associated method for re-engineering a telecommunications network support system with object-oriented translators

Abstract: A re-engineering method for standardizing data processing in a communication network while maintaining user services is disclosed. Data channels, between communicating network data processing components (hereinafter denoted operational components), are made unnecessary by systematically providing bypass data paths. The data on each bypass, transparent to its terminating operational components, is routed through a network manager communicating in a standardized protocol. The manager thereby provides centralized control of data communications and provides standardized object oriented data representations and protocols. For a selected operational component having a bypass for each data channel, the functionality of the selected operational component may be incrementally and transparently assumed by new operational components communicating with the manager. Thus, a selected operational component using nonstandard data representations and communication protocols can be isolated from other network components and deactivated while maintaining user services. The present invention is particularly useful in re-engineering telephony networks having noncentralized and nonstandardized communications between various combinations of network elements and operational support systems.

Method and apparatus for processing multi-protocol communications

Abstract: A method and apparatus for processing multi-protocol communications via a single system is accomplished by receiving a message from a first communications device wherein the message includes the identity of at least a first communications device and a second communications device. When the first communications device utilizes a different communications protocol than the second communication device, the messages transceived between the two communication devices are converted by an appropriate communication protocol. Such conversion is done by first converting an incoming message having a first communication protocol format into a message having a generic communication protocol format. The message having the generic communication protocol format is then converted into a message having a second communication protocol format, which message is subsequently routed to the second communication device.

Communication synthesis for distributed embedded systems

Abstract: Designers of distributed embedded systems face many challenges in determining the tradeoffs when defining a system architecture or retargeting an existing design. Communication synthesis, the automatic generation of the necessary software and hardware for system components to exchange data, is required to more effectively explore the design space and automate very error prone tasks. The paper examines the problem of mapping a high level specification to an arbitrary architecture that uses specific, common bus protocols for interprocessor communication. The communication model presented allows for easy retargeting to different bus topologies, protocols, and illustrates that global considerations are required to achieve a correct implementation. An algorithm is presented that partitions multihop communication timing constraints to effectively utilize the bus bandwidth along a message path. The communication synthesis tool is integrated with a system co-simulator to provide performance data for a given mapping.

TCP/IP network accelerator system and method which identifies classes of packet traffic for predictable protocols

Abstract: A network accelerator for TCP/IP includes programmable logic for performing network protocol processing at network signaling rates. The programmable logic is configured in a parallel pipelined architecture controlled by state machines and implements processing for predictable patterns of the majority of transmissions. Incoming packets are compared with patterns corresponding to classes of transmissions which are stored in a content addressable memory, and are simultaneously stored in a dual port, dual bank application memory. The patterns are used to determine sessions to which an incoming IP datagram belongs, and data packets stored in the application memory are processed by the programmable logic. Processing of packet headers is performed in parallel and during memory transfers without the necessity of conventional store and forward techniques resulting in a substantial reduction in latency. Packets which constitute exceptions or which have checksum or other errors are processed in software.

Networked telephony central offices

Abstract: A communications networking system is disclosed for controlling and monitoring devices within a telephony central office. The networking system includes a high bandwidth local area network (LAN) within the central office for transferring substantially all communications between each central office network element and remote telephony operational support systems (OSSs) that control and monitor network element performance. The LAN simplifies communications within the central office: (a) by substantially eliminating direct connections, between central office network elements and remote OSSs, and (b) by utilizing at least one standardized communication protocol such as TCP/IP, UDP/IP, or OSI when transferring communications over the LAN. The networking system includes a mediation device(s) for translating between network element specific protocols and a standardized protocol used on the LAN. The networking system further includes redundant routers, each acting as an interface between a wide area network (WAN) connecting to the central office and the central office local area network, wherein the WAN provides substantially all of the communications between the central office and the OSSs. One of the routers is used in securing the central office against undesirable access by agents dialing into the central office via the public telephone lines. This router obtains an ID and password from a dial-in agent, and communicates with a remote security center to determine what central office process interfaces the agent may access. The router also prohibits dial-in users from accessing the WAN and thereby accessing other telephony service control sites.

On some challenges and design choices in ad-hoc communications

Abstract: Ad-hoc networks are network architectures that can be rapidly (ideally immediately) deployed and that do not need to rely on pre-existing infrastructure. The salient feature of this breed of networks is that they can operate in different and differing propagation and network operational conditions, which cannot be predicted during the network design stage. We discuss some of the challenges and choices that need to be made while designing an ad-hoc network. In particular, we address the following three issues: hierarchical vs. flat network architectures, proactive vs. reactive (on demand) routing protocols vs. a hybrid approach, and sensing-based vs. dialog-based medium access control.

Patient data acquisition and control system

Abstract: The present invention solves this communication problem by providing a method and apparatus for connecting to and coordinating data communications of various medical devices having different communication protocols. In a preferred embodiment, the invention provides a way to recognize common parameters and separate out only that part of the communication that is different between and specific to the various monitors and therapeutic devices. The invention efficiently utilizes defined common parameters for protocol types and selectively configures the specific settings when required, automatically. The invention also provides the ability to connect devices having standardized communication protocols with pre-defined common communication language.

Improving the performance of distributed applications using active networks

Abstract: An active network allows applications to inject customized programs into network nodes. This enables faster protocol innovation by making it easier to deploy new network protocols, even over the wide area. We argue that the ability to introduce active protocols offers important opportunities for end-to-end performance improvements of distributed applications. We begin by describing several active protocols that provide novel network services and discussing the potential impact of these kinds of services on end-to-end application performance. We then present and analyze the performance of an active networking protocol that uses caching within the network backbone to reduce load on both servers and backbone routers.

An extensible probe architecture for network protocol performance measurement

Abstract: This paper describes the architecture and implementation of Windmill, a passive network protocol performance measurement tool. Windmill enables experimenters to measure a broad range of protocol performance metrics by both reconstructing application-level network protocols and exposing the underlying protocol layers' events. Windmill is split into three functional components: a dynamically compiled Windmill Protocol Filter (WPF), a set of abstract protocol modules, and an extensible experiment engine. To demonstrate Windmill's utility, the results from several experiments are presented. The first set of experiments suggests a possible cause for the correlation between Internet routing instability and network utilization. The second set of experiments highlights: Windmill's ability to act as a driver for a complementary active Internet measurement apparatus, its ability to perform online data reduction, and the non-intrusive measurement of a closed system.

System and method for packet network trunking

Abstract: Concurrent calls are multiplexed over packet network connections such as TCP/UDP/IP connections. Initially, semi-permanent, open channels (e.g., TCP and/or UDP channels) are established between two or more packet switches. The switches format incoming calls, as necessary, and multiplex them onto the open channels. Identifiers may be added to the multiplexed calls to facilitate the demultiplexing of the calls by the receiving switch. The multiplexed calls are encapsulated into packet network protocol packets (e.g., TCP/IP or UDP/IP) for routing over a packet-based network (e.g., IP).

Virtual network transport protocols for Myrinet

Abstract: Bringing direct and protected network multiprogramming into mainstream cluster computing requires innovations in three key areas: application programming interfaces, network virtualization systems, and lightweight communication protocols for high-speed interconnects. The AM-II API extends traditional active messages with support for client-server computing and facilitates the construction of parallel clients and distributed servers. Our virtual network segment driver enables a large number of arbitrary sequential and parallel applications to access network interface resources directly in a concurrent but fully protected manner. The NIC-to-NIC communication protocols provide reliable and at-most-once message delivery between communication endpoints. The NIC-to-NIC protocols perform well as the number of endpoints and the number of hosts in the cluster are scaled. The flexibility afforded by the underlying protocols enables a diverse set of timely research efforts. Other Berkeley researchers are actively using this system to investigate implicit techniques for the coscheduling of communicating processes, an essential part of high-performance communications in multiprogrammed clusters of uni- and multiprocessor servers. Other researchers are extending the active message protocols described here for clusters of symmetric multiprocessors, using so-called multiprotocol techniques and multiple network interfaces per machine.

A fully-pipelined fixed-latency communications system with a real-time dynamic bandwidth allocation

Abstract: The present invention provides for an on-chip communications method with fully distributed control combining a fully-pipelined, fixed latency, synchronous bus (35) with a two-level arbitration scheme where the first level of arbitration is a framed, time division multiplexing arbitration scheme and the second level is a fairly-allocated round-robin scheme implemented using a token passing mechanism. Both the latency and the bandwidth allocation are software programmable in real-time operation of the system. The present invention also provides for a communication system where access to a shared resource (10, 15, 20) is controlled by the communications protocol. Access to and from the shared resource (10, 15, 20) from the subsystem is through a bus interface module (40, 45, 50, 55, 60). The bus interface modules (40, 45, 50, 55, 60) provide a level of indirection between the subsystem (25, 30) to be connected to the shared resource (10, 15, 20). This allows the decoupling of system performance requirements. Communication over the bus (35) is fully memory mapped.

Proportional share scheduling of operating system services for real-time applications

Abstract: While there is currently great interest in the problem of providing real time services in general purpose operating systems, the issue of real time scheduling of internal operating system activities has received relatively little attention. Without such real time scheduling, the system is susceptible to conditions such as receive livelock-a situation in which an operating system spends all its time processing arriving network packets, and application processes, even if scheduled with a real time scheduler, are starved. We investigate the problem of scheduling operating system activities such as network protocol processing in a proportional share manner. We describe a proportional share implementation of the FreeBSD operating system and demonstrate that it solves the receive livelock problem. Packets are processed within the operating system only at the cumulative rate at which the destination applications are prepared to receive them. If packets arrive at a faster rate then they are discarded after consuming minimal system resources. In this manner the performance of "well behaved" applications is unaffected by "misbehaving" applications. We demonstrate this effect by running a set of multimedia applications under a variety of network conditions on a set of increasingly sophisticated proportional share implementations of FreeBSD and comparing their performance. This work contributes to our knowledge of the engineering of proportional share real time systems.

Communication protocol for a vehicle navigation system

Abstract: A method for transmitting data from a navigation system to a vehicle controller in a vehicle having a plurality of systems controlled by the vehicle controller is described. The plurality of systems includes a user interface and the navigation system. A request is received from the vehicle controller for interface data of a particular data type to be presented in the user interface. A first transmission protocol is selected from a plurality of transmission protocols for transmitting the interface data to the vehicle controller. The first transmission protocol is selected based, at least in part, on the data type of the interface data. The interface data are then transmitted to the vehicle controller according to the first transmission protocol.

Mobile networking in the Internet

Abstract: Computers capable of attaching to the Internet from many places are likely to grow in popularity until they dominate the population of the Internet. Consequently, protocol research has shifted into high gear to develop appropriate network protocols for supporting mobility. This introductory article attempts to outline some of the many promising and interesting research directions. The papers in this special issue indicate the diversity of viewpoints within the research community, and it is part of the purpose of this introduction to frame their place within the overall research area.

Distributed network protocols for wireless communication

Abstract: This paper describes a network design strategy that focuses on energy conservation. This position-based network protocol is optimized for minimum energy consumption in wireless networks that support peer-to-peer communication. Given any number of randomly deployed communication nodes over an area, we show that a simple local optimization scheme executed at each node guarantees strong connectivity of the entire network and attains the global minimum energy solution for both stationary and mobile networks.

Organizing multicast receivers deterministically by packet-loss correlation

Abstract: The ability to trace multicast paths is currently available on the Internet by means of Internet Group Management Protocol MTRACE packets. We introduce Tracer, a protocol that organizes the receivers of a multicast group deterministically into a logical tree structure while maintaining exact packet-loss correlation for local error recovery, and without requiring any changes to existing multicast routing protocols. Tracer uses MTRACE packets in the Internet Group Management Protocol to allow a receiver host to obtain its path to the source of a multicast group. Receivers use the multicast path information to determine how to achieve local error recovery and effective congestion control. We compare the tracing approach with prior mechanisms that attempt local recovery. Results of measurements carried out over the Collaborative Advanced Internet Research Network illustrate the fact that tracing multicast paths is an effective tool to organize receivers based on their packet-loss correlation.