Showing papers on "Internetwork protocol published in 1995"

Improving reliable transport and handoff performance in cellular wireless networks

Abstract: TCP is a reliable transport protocol tuned to perform well in traditional networks where congestion is the primary cause of packet loss. However, networks with wireless links and mobile hosts incur significant losses due to bit-errors and hand-offs. This environment violates many of the assumptions made by TCP, causing degraded end-to-end performance. In this paper, we describe the additions and modifications to the standard Internet protocol stack (TCP/IP) to improve end-to-end reliable transport performance in mobile environments. The protocol changes are made to network-layer software at the base station and mobile host, and preserve the end-to-end semantics of TCP. One part of the modifications, called the snoop module, caches packets at the base station and performs local retransmissions across the wireless link to alleviate the problems caused by high bit-error rates. The second part is a routing protocol that enables low-latency handoff to occur with negligible data loss. We have implemented this new protocol stack on a wireless testbed. Our experiments show that this system is significantly more robust at dealing with unreliable wireless links than normal TCP; we have achieved throughput speedups of up to 20 times over regular TCP and handoff latencies over 10 times shorter than other mobile routing protocols.

Method for reducing unnecessary traffic over a computer network

Abstract: Standard protocols, such as those commonly used on LAN networks, are used to connect nodes to an enterprise network via a wide area wireless network. Within the appropriate protocol stacks, the standard protocols are optimized by filtering some packets, eliminating and reducing the size of other fields and substituting still other fields to reduce the size of the data packets. The optimized data packets can be transmitted over the wireless WAN increasing WAN efficiency. The optimization is accomplished by inserting an additional optimization layer into the protocol stack between the existing layers. The optimization layer accepts the normal protocol signals generated by the surrounding layers and generates outputs which mimic protocol layers which the surrounding layers expect. Consequently, the optimization layer operates transparently with respect to the existing protocol stack layers.

System and method for establishing communication protocols between application programs

Abstract: A method and system for implementing a common protocol for communication of data between a first application program and a second application program. The method and system uses a high level interface specification that is created in a computer program language-independent fashion using an object oriented paradigm. The high level interface specification is used to define the common protocol, and to generate first and second protocol interfaces. Either of the generated first and second protocol interfaces is capable of performing the services of a client or server, and are inserted into the first and second application programs respectively. The first and second protocol interfaces are executed by the first and second application programs for communication of data between them using the common protocol.

Method and apparatus for forwarding traffic between locality attached networks using level 3 addressing information

Abstract: A method and apparatus for layer 3 switching packets between locally attached virtual local area networks without using a routing protocol are provided. A learning internetwork switch is connected between a router and a plurality of virtual local area networks. Communications between devices on the virtual local area networks and the router pass through the learning internetwork switch. By inspecting certain packets that flow between the devices and the router, the learning internetwork switch learns the location of the devices without having to use a routing protocol. The learning internetwork switch learns the network layer and the data link layer addresses of the various devices. Once the learning internetwork switch has learned the location, the network layer address and data link layer address of a device, the learning internetwork switch can forward packets between devices on different virtual local area networks using layer 3 switching without involving the router.

A multilevel WDM access protocol for an optically interconnected multiprocessor system

Abstract: Scalable, hierarchical, all-optical WDM networks for processor interconnection in multiprocessor systems have been recently considered. The principal objective of this paper is to introduce an access protocol for this type of network which supports a distributed shared memory (DSM) environment. The objectives of the protocol are reduced average latency per packet, support of broadcast/multicast, collisionless communication, and exploitation of inherent DSM traffic characteristics. The protocol is based on a hybrid approach that combines reservation access and preallocated reception channels for a WDM system. The proposed approach trades maximum capacity for reduced communication latency to improve system response. The performance of the protocol is analyzed through semiMarkov analytic and simulation models with varying system parameters such as number of nodes and channels. The performance of the new protocol is compared to a TDM-based protocol and their relative merits are examined.

Automatic test environment for communications protocol software

Abstract: A test system and method are disclosed for testing a communications protocol software implementation or combination of communications protocol software implementations. The test system has a memory for storing a communications protocol software implementation of a particular layer in a hierarchy of protocols. The test system has a processor for catching data outputted from the communications protocol software implementation to upper and lower layer communications protocol software. The processor is also for interpreting each frame contained in a test case file. In response to interpreting an input data frame, the processor feeds input data contained in the input data frame to the communications protocol software implementation. In response to interpreting an output data frame, the processor compares received data outputted from the communications protocol software implementation with expected output data interpreted from the output data frame, and generates a message depending on this comparison. Furthermore, the processor may simultaneously monitor the execution of the communications protocol software implementation and generate a wake-up message if the communications protocol software implementation properly or unexpectedly ceases execution. In response to receiving a wake-up message, the processor writes an appropriate message in a test report file.

Testing to assure interworking of implementations of ISO/OSI protocols

Abstract: At the Institute for Computer Sciences and Technology of the national Bureau of Standards, an architecture has been specified for testing protocols in layers four through seven of the International Organization for Standardization's (ISO) Basic Reference Model for Open Systems Interconnection (OSI). This paper describes the application of that architecture to testing Class 4 Transport with thirteen vendors' implementations of the protocols prior to a demonstration of ISO protocols at the National Computer Conference in 1984. The test results are summarized and an evaluation of the architecture and individual tools is presented. The paper concludes with a summary of a more ambitious demonstration of networking using implementation of ISO protocols.

A loss-free connection control protocol for the Thunder and Lightning network

Abstract: The ready-to-go virtual circuit protocol (or RGVC) is a novel connection control protocol for gigabit networks that is designed to ensure lossless transmission for delay-sensitive traffic and for traffic whose rate changes with time. The RGVC protocol is one of the two connection control protocols that will be used in the 40 Gbit/s fiber-optic ATM-based Thunder and Lightning network, currently being developed at UCSB. We introduce the RGVC protocol, discuss its main features, and indicate its lossless character. The RGVC protocol can be viewed as a reservation protocol where the reservation and the data transmission phases overlap. The source need not wait for an end-to-end round-trip delay for reservations to be made before transmitting the data. Instead the data packets follow the setup packet after a short offset-interval, which is much smaller than the round-trip delay. As a result, the protocol does considerably better than wait-for reservation protocols in terms of minimizing pre-transmission delay, and is useful for connection establishment for traffic with strict delay requirements. If the setup packet is unsuccessful in reserving the required capacity, or if the rate of the session changes without there being sufficient capacity to accommodate the change, the packets are buffered at intermediate nodes and back-pressure is exercised to the upstream nodes to control the source transmission rate. The back-pressure mechanism uses the concept of freezing of capacity to ensure that the protocol is lossless.

A dynamic adaptive multi-receiver random access protocol for the code division multiple access channel

Abstract: We present a packet multiple access protocol that is a hybrid of a pure CDMA protocol and an ALOHA random access protocol. The protocol utilizes the multireception capabilities of spread-spectrum communications together with the "statistical-multiplexing" capabilities of random access. We begin by presenting a multi-receiver random access protocol and analyze its throughput characteristics. We then develop collision resolution algorithms for the protocol that attempt to optimize its performance. These algorithms are analyzed through the use of simulation. We show that with proper choice of protocol parameters our protocol can handle all admissible traffic loads. We then propose a dynamic, adaptive extension to the protocol that uses limited feedback information to allow the protocol to vary its parameters based on the traffic load in the system. This dynamic, adaptive version of the protocol allows it to operate efficiently under a wide variety of traffic load conditions. At very light load conditions the protocol behaves as a pure random access protocol and at very high load it behaves as a pure fixed assignments protocol. Our protocol seems to be a good choice for providing random access on a satellite channel where propagation delays are long. It is also a natural choice for wireless transmission of very short (e.g., ATM) packets.

A method for internal communication in a telecommunications system

Abstract: In traffic processes in a telecommunication system there is internal communication between service controlling entities which may belong to logical nodes in the same or different applications (6, 8, 10). Such a service controlling entity may e.g. be a service process controlling a service for a party of a call. The communication between the service controlling entities is controlled by means of rules given in a generic protocol. These rules imply lack of messages and use only of protocol parameters in the form of indivisible information transmission elements. Based upon the generic protocol service protocols (ASP) are specified each corresponding to its service, a protocol managing entity (ASPE) within an application handling the protocol management of a certain service according to the service protocol (ASP). The information elements are distributed by a communication service (ITS) having a parameter distribution function for said parameters, by transferring data between the protocol managing entities (ASPE).

Protocol architectures for delivering application specific quality of service

Abstract: With the advent of high speed networks, the future communication environment is expected to comprise a variety of networks with widely varying characteristics. The next generation multimedia applications require transfer of a wide variety of data such as voice, video, graphics, and text which have widely varying access patterns such as interactive, bulk transfer, and real-time guarantees. Traditional protocol architectures have difficulty in supporting multimedia applications and high-speed networks because they are neither designed nor implemented for such a diverse communication environment. In this paper, we analyze the drawbacks of traditional protocol architectures and propose two alternative architectures for the next generation high-speed network environment: Direct Application Association and Integrated Layered Logical Multiplexing. We implement sample protocol stacks for each of the above models using the most widely used protocol stack (TCP/UDP-IP-Ethernet) in the context of the x-kernel. The performance of these protocol architectures is shown to be comparable to that of a traditional protocol architecture. They win by enabling the key requirements (Application specific Quality of Service) and optimizations (Integrated Layer Processing) necessary for future communication environments.

TCP/IP for everyone

Abstract: Internetworking models aand conceptual tools networking addresses, network names internetwork architecture - bridges, routers gateways network implementation issue TCP/IP applications the data link layer the Internet protocol routing protocols user datagram protocol transmission control protocol TCP/IP host name resolution remote computing - Telnet and r-Utilities file transfer protocols - FTP and TFTP network communications - electronic mail and news netwrok data publishinh - gopher and the World Wide Web resource sharing - network file system configuring Windows 95 for TCP/IB.BOOTP and DHCP TCP/IP internetwork management TCP/IP and internetwork security. Appendices: Internet history and organizations IP, the next generation.

Protocol configuration and interoperability-a case study

Abstract: Providing an application-tailored communication protocol increases the exploitation of service specific characteristics by any application. Especially, the configuration approach of communication protocols according to specified and requested application quality-of-service (QoS) requirements offers a highly flexible scenario to allow for a sufficient and appropriate protocol processing. The approaches of the function-based communication subsystem (F-CSS) and the dynamic configuration of protocols (Da CaPo) provide a basis for configuring specifically requested services. An important aspect for a future integration into the existing networking environment is the interoperability of configuration-based approaches. The case study presented evaluates the possibility of F-CSS and Da CaPo interoperability.

Fail-Stop Protocols: An Approach to Designing Secure Protocols (Preprint)

Abstract: : We present a methodology to facilitate the design and analysis of secure cryptographic protocols. We advocate the general approach, and a new avenue for research, of restricting protocol designs to well-defined practices, instead of ever increasing the complexity of protocol security analysis mechanisms to deal with every newly discovered attack and the endless variations in protocol construction. In particular, we propose a novel notion of a fail-stop protocol, which automatically halts in response to any active attack that interferes with protocol execution, thus reducing protocol security analysis to that of passive attacks only. We suggest types of protocols that are fail-stop, outline some proof techniques for them, and use examples to illustrate how the notion of a fail-stop protocol can make protocol design easier and can provide a more solid basis for some available protocol analysis methods.

Performance-bound analysis of the new DS/SSMA protocol for wireless data networks

Abstract: The code protocol (the R/sup 3/ protocol) for DS/SSMA wireless data networks is examined further and an analytical method is given of studying its delay and throughput bounds. In this protocol the communication-initiation process terminals uses handshaking packets (REQ and ACK packets), followed by the data packet. Different chip rates are utilised in transmissions of different packets to avoid destructive collisions between them. All packets are encoded by receiver-based codes. It is shown that the throughput lower bound of this protocol is about 0.24 when the normalised offered channel-traffic load is equal to one, and that the protocol offers stability to the network even at a very high offered channel-traffic load.

Considerations in running TCP/IP-based networks over the X.25 public data network

Abstract: The TCP/IP Internet protocol suite is the most popular networking standard for interconnecting heterogeneous computer systems in a variety of communication network environments. This paper presents some considerations in running the IP network protocol on top of an X.25 network interface. The system architecture is given first. The main focus here is on the performance of a connectionless network protocol run over a connection-oriented network protocol. Appropriate settings for an inactivity timer and the effect of special higher layer protocol operations are discussed. We also consider issues which arise in relation to address resolution, network management and security.

Internetworking between TP4 and TCP through protocol complementation

Abstract: Like protocol conversion, protocol complementation is an approach for network interconnection. This paper describes the internetworking between TP4 and TCP at the transport level through protocol complementation. This applies to the need for interoperability between ISO-OSI and Internet. From the given CFSM specifications of protocol P[P/sub s/,P/sub r/] of TP4 and Q[Qs,Qr] of TCP, we have constructed a composite protocol CFSM R/sub PQ/ for the converter which may be inserted as a virtual layer to provide a uniform view to the users. An attempt has been made to implement the converter through Estelle-C (Extended State Transition Language) compiler, a formal description tool for protocol specification and verification. >

Experiences with a protocol stack for multimedia transport

Abstract: Our experiences with the BERKOM MMT protocol stack are reported. The MMT protocol stack is aimed at multimedia data communications. It consists of the ST-II protocol at the network layer and a modified version of the XTP protocol called XTP-Lite at the transport layer. The specific features of the protocol stack are presented and the implementation in a SUN environment is detailed. Related performance measurements are also given to support our conclusions. The protocol stack is the core of the BERKOM multimedia transport system (MMTS). The MMTS is designed for communication between distributed multimedia applications on top of broadband ISDN networks.

Performance modelling for a distributed ISDN protocol test system

Abstract: Conformance testing of communication protocols has recently become a major issue in the context of OSI-based standardization of protocols. The aim of conformance testing is to assure that a protocol fulfils an OSI specification. A performance study is presented for a distributed protocol test system that has been installed for conformance testing of the ISDN D-channel signalling protocol. Using a general approach for performance measurements and evaluation in distributed systems, a queueing model is developed and evaluated, based on runtimes as obtained from measurements of the test system. It is demonstrated that significant performance improvements can be achieved once the process scheduling strategy at the ISDN protocol testers is properly adjusted. >

Efficiency comparison of real-time transport protocols

Abstract: In this paper we consider the problem of providing efficient network support to distributed real-time applications with different communication requirements. In the case of resource reservation protocols, the level of efficiency of a transport service connection provided by a communication system is influenced by the applications requirements, in terms of amount of network resources needed to provide guaranteed Quality of Service. We consider the Tenet protocol suite, a connection-oriented internetworking set of protocols based upon resource reservation. The suite provides a real-time network service (i.e., a service with guaranteed performance) to two types of applications: continuous media (CM) clients that generate data at regular time intervals (e.g., video and audio); message oriented clients that generate data at arbitrary times (e.g., urgent messages and remote control applications). We compare the performance of the transport protocol for CM clients (CMTP) to that of the transport protocol for message oriented clients (RMTP). In particular, we consider the buffer usage in the underlying real-time internetwork protocol (RTIP). The results of the simulations show that in the CMTP case, by taking advantage of the regular nature of CM clients, proper mechanisms can be adopted to further smooth traffic, so that buffers are used much more efficiently than in the RMTP case.

CHANNELS -Time System for Multimedia Protocols

Abstract: This paper presents CHtWNELS, a run-time system for network protocol processing. CHMNELS is especially intended and optimized for transport systems supporting multimedia applications on high-speed networks. Additionally to the traditional features of a run-time system like the scheduling of the processing of different protocols, the provision of dedicated facilities such as timer, buffer and mapping table libraries for protocol implementation and the support of the communication to adjacent protocol entities, network devices and user processes, CHANNELS enables the implementation of sophisticated protocols which require real-time and parallel processing capabilities, or dynamic protocol configuration support. CHANNELS is implemented in the C++ programming language and one prototype is embedded in the SUNIUNIX kernel.

A new protocol for optical high-speed packet-switched networks

Abstract: A new media access protocol for optical high-speed packet-switched networks is proposed. The protocol is based on a broadcast passive optical star coupler topology. The strength of the protocol is its simplicity. The protocol supports a network architecture consisting of tunable transmitters and tunable receivers. Each station has a data channel and a control/signalling channel. The data channel wavelength is unique to each station while several stations can share a common control channel wavelength. Both connection-oriented and datagram traffic can be supported by this protocol. No network wide synchronization is required and hence it is suitable to LAN/MAN applications in which it is extremely difficult to achieve network synchronization. Analysis of the proposed protocol is presented.

Performance evaluation of a lightweight logical link control protocol in slotted ring networks

Abstract: This paper evaluates the performance of a fast select connection oriented (FS-CO) logical link control (LLC) protocol in slotted ring networks. the FS-CO-LLC protocol is one of the light-weight protocols. It employs a method of implicit connection establishment and release to reduce overhead of connection control. l'his paper analyzes the performance (throughput and average response time) of a slotted ring network in which a single slot circulates by means of Equilibrium Point Analysis. the performance in the case of plural slots is evaluated by simulation. This paper also compares the FS-CO-LLC protocol with connection-oriented (CO) and connection-less (CL) LLC protocols. Numerical results show that the performance of FS-CO-LLC and CL-LLC protocols is superior to that of CO-LLC protocol when the average message length is smaller than the buffer size. On the other hand, when the average message length is larger than the buffer size, CO-LLC protocol has the best performance. It is also shown that the per formance of FS-CO-LLC protocol does not-degrade but CL-LLC protocol does, even if the average message length becomes larger.

Secure data communication protocols in bidirectional star network

Abstract: The author describes a secure data communication method based on the CSMA/CD protocol in bidirectional star networks. A procedure for detecting packet collision while transmitting the jamming signal is required. The author assess two kinds of protocol, a CRV (code rule violation) protocol and a DR (delayed replying) protocol.