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Local Computer Networks, 1991. Proceedings., 16th Conference on

Date 14-17 Oct. 1991

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  • Proceedings. 16th Conference on Local Computer Networks (Cat. No.91TH0397-0)

    Publication Year: 1991
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    Freely Available from IEEE
  • Making transport protocols fast

    Publication Year: 1991 , Page(s): 295 - 300
    Cited by:  Papers (5)  |  Patents (1)
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    An international group of researchers, led by Dr. G. Chesson at Silicon Graphics Inc., has developed a new transport+network protocol for modern distributed computing systems. Extant protocols (e.g. TCP, TP4, Delta-t, NETBLT, GAM-T-103, VMTP, URP) were first examined to understand their solutions to common data transfer problems. Then, a new protocol called XTP (Xpress Transfer Protocol) was developed which both reuses ideas known to be good and breaks new ground in the definition and delivery of communications services. XTP is specifically designed for implementation in hardware as the Protocol Engine which will connect to a commercial FDDI chipset. The author reports first on the philosophy underlying XTP's design, and then on his experiences in producing a software implementation View full abstract»

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  • Management of switched multimegabit data service (SMDS) using the simple network management protocol (SNMP)

    Publication Year: 1991 , Page(s): 362 - 368
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    The emerging switched multimegabit data service (SMDS) and the simple network management protocol (SNMP) are being coupled together, providing the opportunity for unique management capabilities. These unique capabilities include mechanisms for customers to retrieve management information directly from their SMDS service provider. It is also anticipated that the combination of SNMP and SMDS will lead to new opportunities for the SNMP management framework within telephony. This paper provides an overview of SMDS, SNMP, and the two is in combination. The challenges associated with using SNMP to manage SMDS are identified and discussed View full abstract»

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  • A two-level threshold-based traffic control scheme for ATM networks

    Publication Year: 1991 , Page(s): 230 - 236
    Cited by:  Papers (3)
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    Emerging multimedia communication networks differ from transitional data networks in that they use very high speed transmission facilities and they carry various types of traffic with different performance requirements. So, effective communication protocols that encounter for several traffic and performance characteristics need to be developed in order to meet the required QOS (quality of service) for the various types of traffic carried. Moreover, the interactions among protocols of different communication layers have to be examined in order to ensure an efficient and high performing operation. The authors are concerned with the bandwidth allocation protocol problem. They address some recently developed approaches to the problem, and examine the two lower layers of a communication subnetwork. They consider the call and packet/cell layers where they assume that two types of traffic are carried. They propose a threshold based approach to the call admission problem in the call level and examine the need for flow control in the packet/cell level. They examine various performance measures and show that the correct choice of performance measures and the sizing of the various network parameters play a significant role in a network operation View full abstract»

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  • Efficient fault-tolerant routing algorithms for forward loop backward hop networks

    Publication Year: 1991 , Page(s): 408 - 417
    Cited by:  Papers (1)
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    Forward loop backward hop (FLBH) networks, characterized by a forward loop connecting all the adjacent nodes and a backward loop connecting nodes separated by a distance of h hops, have a higher connectivity and therefore a higher potential for fault-tolerance than single-loop networks. How to devise efficient fault-tolerant routing algorithms is an important issue on designing FLBH networks. This paper proposes two new fault-tolerant routing algorithms. One is for optimal FLBH networks with h2=N, where N is the number of nodes. The other is for arbitrary FLBH networks (i.e., 1⩽hN-1). Both algorithms are theoretically shown to be able to guarantee that any packet is sure to reach its destination even when a faulty node exists. At the same time, they are simple and merely require local knowledge. A simple and effective rule, called the balancing rule, is used to determine the next node to which the incoming packet should be forwarded. The balancing rule enables the algorithms to find the shortest path between the source and the destination in most cases despite the presence of network faults. The results of computer simulations demonstrate that the average length of paths discovered by the authors' algorithms is shorter than that found by other algorithms and is near optimal solution. As a result, these algorithms are suitable for implementation on practical local computer networks, especially on large ones View full abstract»

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  • An expert integrator for communication networks management

    Publication Year: 1991 , Page(s): 369 - 374
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    Network management is a difficult problem. How to manage the multi-vendor network efficiently and effectively has become a growing concern in the international communication networks community. OSI management has defined a basic set of facilities (functional areas) that the network management should provide. The authors propose an integrated architecture which allows the expert systems, one for each functional area, to work together in an organized way. An additional expert, namely the integrator, sits on top of the five functional experts. It passes the triggering data received from the network components to the appropriate functional experts that understand a specific network problem. In this architecture, OSI network management protocols are used as means of communications among experts. An object-oriented database and a generic user interface are presented View full abstract»

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  • Interfaces, modularity and path lengths: the costs of implementing OSI transport

    Publication Year: 1991 , Page(s): 452 - 466
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    Performance of communication software is influenced both by the underlying protocol architecture and by implementation. The debate as to which of the two kinds of factors dominates the overall performance has been going on for many years. The author discusses this issue by reporting on detailed performance measurements of his experimental OSI transport system. He focuses on the analysis and classification of the path lengths involved during data transfer, obtaining insight into the relative costs of protocol functions versus system-level design and implementation choices. His main conclusion is that adherence to general-purpose protocol standards is not the true bottleneck. The desire to provide a flexible general-purpose portable implementation with open inter-layer interfaces causes most of the overhead View full abstract»

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  • The multiple switch-connected token passing ring networks

    Publication Year: 1991 , Page(s): 544 - 553
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    A pairwise switch-connection mechanism for interconnecting multiple token passing ring networks is proposed. The total number of internetwork packet store-and-forwards occurring at the bridges can be significantly reduced under the new switching method. A simple scheduling algorithm is developed to guarantee non-overlapped pairwise connection among the interconnected ring networks. Easy network access can be achieved through the use of different types of free tokens and local timers. Only simple table look-up operation is needed for the internetwork address translation. Therefore, the internetwork packets can be routed efficiently. Finally, simulation results are provided to show the fair network throughput under such switch-connection approach View full abstract»

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  • Analysis of CISC versus RISC microprocessors for FDDI network interfaces

    Publication Year: 1991 , Page(s): 485 - 493
    Cited by:  Papers (2)
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    In recent years, RISC manufacturers have focussed attention on the enhanced performance of RISC microprocessors in meeting high speed microprocessor requirements. FDDI has such needs at the network to host computer interface. This paper presents design alternatives for the network interface and a model that can be used to examine the achievable throughput assuming different CISC and RISC processors. The model indicates that the CISC processors may outperform the RISC processors in FDDI and other high speed networks where data movement requirements are significantly larger than the protocol processing overhead View full abstract»

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  • An evaluation of priority consistency in protocol architectures

    Publication Year: 1991 , Page(s): 386 - 398
    Cited by:  Papers (5)  |  Patents (2)
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    Workstations for digital audio and video applications must support predictable processing, presentation, and transmission of continuous media data while making efficient use of limited hardware resources. The authors present techniques for managing network resources and processing messages in a predictable fashion. Their solutions use a novel structure for the protocol processing software, and they examine several alternatives and discuss the engineering tradeoffs associated with each. Using simulation, they evaluate their protocol processing structures and show that the more sophisticated structures can improve the response time and predictability of time-constrained messages. The ideas presented in this paper can be applied to resource management in the operating system and to the structuring of application-level servers. The designers of gateway machines (for internetwork routing) which handle both time-constrained traffic and non-time-constrained traffic may also benefit from this study View full abstract»

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  • Performance evaluation of FDDI-what about packet loss?

    Publication Year: 1991 , Page(s): 18 - 23
    Cited by:  Papers (5)
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    Recently, a discussion came up dealing with the frame copied indicator in the frame status sequence of FDDI. This indicator shows whether or not the destination has copied the frame and this way allows the sender to react in a proper way. However, in interconnected networks the destination node may represent a large number of destinations with different addresses making it difficult to check within a very short time whether a certain packet is to be copied and the indicator is to be set. The paper discusses the effect of using or not using the frame copied indicator. Additionally, it proposes a class of new congestion control strategies for FDDI View full abstract»

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  • ATM traffic characterization

    Publication Year: 1991 , Page(s): 237 - 246
    Cited by:  Papers (3)
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    This paper treats characterization of ATM traffic. As the connection acceptance control, the policing and last but not least the terminal equipment are concerned with traffic characterization, this issue is of special importance. This paper first develops theoretical traffic characterizers to be used in theory and simulation, and then proposes a single parameter-the equivalent offered traffic-to be implemented to characterize ATM traffic. This parameter has the advantage of being simple, policeable and allows the use of linear connection acceptance control algorithms View full abstract»

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  • A simulation study on a high-speed slotted-ring access mechanism with dynamically adaptive slot sizes

    Publication Year: 1991 , Page(s): 106 - 113
    Cited by:  Papers (2)
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    Two access mechanisms complementary in performance are the token ring and the slotted ring. While the token ring outperforms the slotted ring for long messages, the latter performs significantly better for short messages. The paper shows that the factor that causes this difference is the number of tokens on the ring. It proposes a new network design in which the number of tokens has been made adaptive, resulting in a network that can be made to behave like both the token ring and the slotted ring, or anything in between, i.e. it performs optimally for any given message length. The paper presents first simulation results that show the performance gain that is achieved by using this principle. Further, it introduces a new priority mechanism in which an upper bound for the access delay of high priority messages is guaranteed View full abstract»

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  • Priority-based dynamic access policies to WAN from LAN/MAN

    Publication Year: 1991 , Page(s): 214 - 222
    Cited by:  Papers (2)
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    The authors consider the integration problem of LAN/MAN traffic to WAN by ATM/SONET multiplexing. They propose separate buffers for voice and data to efficiently control the throughput of each traffic type. Transmission bandwidth is dynamically and adaptively shared between voice and data to guarantee grade of service (GOS) requirements for each traffic type. The authors propose two algorithms for access policies; the (N1,N2) scheme and its adaptive variation. Their algorithms do not require the knowledge of arrival statistics. In the fact scheme, they can play with the tradeoff between delay and cell loss probability of each traffic type. In the second scheme, for most of the time and under normal network conditions, voice traffic has higher priority. Data traffic has higher priority when the number of data cells queued reaches a certain threshold. They show how the network performance is affected by several system parameters View full abstract»

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  • Experimental evaluation of transport layer protocols for real-time applications

    Publication Year: 1991 , Page(s): 521 - 534
    Cited by:  Papers (6)
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    Several transport protocols have been proposed for use in the Internet. The specifications of these protocols are based on the assumption that a general purpose transport protocol can be designed to be used by a variety of applications, including time-constrained applications. A widespread consensus among the researchers is that a general purpose transport protocol is not optimized for any applications, and thus cannot deliver the high performance required by real-time applications such as voice, motion and still video, and large file transfer. This paper investigates the validity of the above claim based on the gathering of empirical data. A generic `protocol benchmark' is used to assess the real-time performance of a set of known transport protocols, and to analyze their suitability to handle the requirements of real-time applications View full abstract»

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  • 16 Mb/s token ring on unshielded twisted pair cabling

    Publication Year: 1991 , Page(s): 67 - 72
    Cited by:  Patents (1)
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    Local area networks operating on structured cabling systems using unshielded twisted pair (UTP) cable are finding increased utilization. These systems provide low cost installation and easy administration. The paper addresses the technical issues concerning the implementation of a robust and practical 16 Mb/s token ring LAN using unshielded twisted pair cabling for lobe connections. Three technical approaches are presented and evaluated for both common unshielded twisted pair cable and new high performance unshielded twisted pair cable. It is shown that 16 Mb/s token ring can operate with lobe lengths of 300 feet on both types of UTP cables provided the appropriate technical approach is implemented View full abstract»

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  • Integrated Access to heterogeneous databases using forthcoming OSI standards

    Publication Year: 1991 , Page(s): 611 - 620
    Cited by:  Papers (1)  |  Patents (1)
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    Integrated access to distributed data managed by heterogeneous database management systems is a critical requirement in most organizations. ISO's OSI appears to be the most promising systems integration framework for providing integrated access to heterogeneous databases. ISO is currently advancing key standards to meet this requirement. The paper presents a functional overview of these forthcoming database access standards and a strawman architecture for integrated database access. It also discusses the use of these standards for supporting integrated access to nonrelational systems. Practical aspects such as standardization schedule and vendor and user support are also discussed View full abstract»

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  • IAPA: a new protocol architecture based on interacting activities

    Publication Year: 1991 , Page(s): 418 - 427
    Cited by:  Papers (1)
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    As the throughput of communication channels grows to the order of GBits/s, communication protocols become the bottleneck in communication applications. The reason for this bottleneck resides partly in the layered protocol architecture, and partly in the complexity of the protocols. This paper presents a new protocol architecture that potentially reduces the protocol overhead by providing a more flexible design structure, giving the opportunity to design protocols suitable for efficient, parallel implementation View full abstract»

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  • Replication management in large networks

    Publication Year: 1991 , Page(s): 629 - 637
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    The replication of data objects in a large computer network is a difficult task which cannot be approached by simply employing the techniques used in small networks, because the high replication factors possible raise new issues which must be addressed. The paper presents a solution to the problem of managing replicas in a large scale environment. The solution is based on a multi-level quorum algorithm for maintaining the consistency of replicas, a probabilistic addressing mechanism for efficiently locating replicas in the system and an efficient scheme for handling dynamic changes in the number of replicas. The feasibility of this approach is demonstrated by presenting performance measurements in a simulated network View full abstract»

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  • Defense data network management system

    Publication Year: 1991 , Page(s): 375 - 377
    Cited by:  Patents (1)
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    The management system provides network management of defense related computer networks for the armed services within the Continental United States (CONUS). The architecture is discussed from the standpoint of the flow of diagnostic information and the role of equipment and personnel. The hierarchy of the network management is discussed to give the overall picture of the network management system View full abstract»

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  • All optical multichannel multihop networks

    Publication Year: 1991 , Page(s): 288 - 294
    Cited by:  Papers (3)
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    A photonic packet switching communication network is presented and its feasibility is discussed. In particular, it is explicitly supposed that the electro-optical conversion is done only by the end users, while all other network functions (transmission, signal processing, routing, etc.) are implemented by photonic circuits. To interconnect the independent channels obtained by partitioning the global optical bandwidth, the class of topologies, called extended shufflenet, is considered. Two particular networks of this class (multiwavelength loop and extended shufflenet with shared channels), which have routing algorithms simple enough to be implemented by photonic circuits, have been analyzed. The photonic architecture developed for the multiwavelength loop has been applied to the extended shufflenet, which is a feasible possibility for a network with a sustained capacity of the order of the gigabit/s per user. The photonic components used in these circuits have been demonstrated in various laboratories and essentially comprehend delay lines, optical switches, simple optical gates, frequency converters, optical filters, etc. Some of these components have been experimentally integrated in subsystems and the implementation of the proposed circuit with today technology appears feasible View full abstract»

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  • Graceful insertion and removal of stations in FDDI networks

    Publication Year: 1991 , Page(s): 494 - 502
    Cited by:  Papers (2)
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    The effects of station insertion and removal from concentrators attached to the dual ring in FDDI networks are examined. The frame-loss caused by the insertion and removal of stations is compared to the frame-loss caused by the ring bit error rate (BER). This is found to be significant for most FDDI networks. Algorithms for 'graceful' insertion and removal are proposed to minimize the impact of these actions on the network performance. The effect on the network bandwidth of the proposed solutions is compared to the effect of normal insertion and removal. Overall, the merits of graceful insertion and removal are found to be marginally significant View full abstract»

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  • Overcoming bottlenecks in high-speed transport systems

    Publication Year: 1991 , Page(s): 399 - 407
    Cited by:  Papers (2)  |  Patents (20)
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    An architecture is presented for HSLAN/MAN controllers. This front-end processor system (FEP) is designed for operation in a CLN/LLC 1 environment, and implements the ISO OSI TP4 transport protocol. The FEP uses one or more commercial microprocessors with layers 2b-4 implemented in firmware. The protocol processors are supported by custom VLSI hardware such as a checksummer, DMA units, and process coupling devices as required. Layers 1 and 2a are provided by commercial chipsets. The FEP is optimised for a LAN/MAN environment while allowing the host to communicate over wide-area networks. It is general enough to be adapted to non-OSI protocol suites. Initial estimates indicate that the FEP should be able to transmit and receive at full FDDI bandwidth with a TPDU length of 1k octets View full abstract»

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  • A ring purger for the FDDI token ring

    Publication Year: 1991 , Page(s): 503 - 514
    Cited by:  Papers (1)
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    The fiber distributed data interface (FDDI) is a 100 Mb/s token ring which includes extensive reliability and robustness mechanisms to provide fault detection, isolation, monitoring, and recovery functions. The authors examine two well-known problems on token rings and their potential impact on FDDI. The two problems are no-owner frame (NOF) and duplicate tokens. FDDI effectively resolves these problems only when either the NOF or the duplicate token collides into a transmitting station. The impact of NOFs and duplicate tokens during the period from the occurrence of the NOF and the duplicate token until they are removed by a transmitting station can be severe. This paper presents a ring purger that transparently and continuously removes the NOFs and detects and removes duplicate tokens. A ring purger is a designated station on a ring that performs its normal functions as a station and, in addition, performs the removal of NOFs and duplicate tokens. A distributed election algorithm is used to elect a single station on a given ring to be the ring purger. The authors also present performance and robustness considerations used in the design of the ring purger algorithms. They study the performance effect of continuously purging the ring and show that the effect is negligible even in the worst case View full abstract»

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  • Ethernet performance under actual and simulated loads

    Publication Year: 1991 , Page(s): 569 - 581
    Cited by:  Papers (5)
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    The paper presents the results of an experiment measuring Ethernet performance using station monitoring. In station monitoring the network measurements are performed internal to the stations, thus enabling the collection of delay information unavailable to typical spying network monitors. The experimental measurements are compared against similar measurements made using Ethernet simulation of the same network. The data show that measured performance differs significantly from predictions made by typical analytical and simulation models. The results have implications for the underlying assumptions used in simulation and modeling and on the use of spying monitors View full abstract»

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