Showing papers on "Media access control published in 1992"

Method and apparatus for analyzing networks

Abstract: The present invention provides a method and apparatus for analyzing and monitoring network activity. The present invention provides one-hundred percent data capture for complete monitoring capability. The present invention also permits the simulated generation of traffic up to network capacity. The method and apparatus of the present invention allows for the use of pre-defined or custom-designed network tests so that users can analyze protocols and trouble-shoot network problems at various levels. Although one-hundred percent data capture is possible, the user may also customize the system to capture only certain packets of information. For example, the present invention can be implemented to capture errors, collisions and short-length packets. The present invention accesses the token ring network through a ring interface. The output of the ring interface is coupled to a media access control (MAC) block. The MAC block includes a memory for packet buffering and is coupled to the primary memory, which is coupled to the host interface. The output of the ring interface is also coupled to a serial state machine. The serial state machine is used for high speed decoding of packet information. The output of the serial state machine is coupled to a series of timers and filters tracking information from the data stream. An on-board CPU controls the timers and is coupled to the primary memory.

In an Interactive network board, a method and apparatus for storing a media access control address in a remotely alterable memory

Abstract: Method and apparatus for storing a Media Access Control (MAC) address in an EPROM disposed on a target interactive network board having a local area network interface comprises the step of activating a LAN communication program. The communication program operates to broadcast an inquiry through the LAN for the target interactive network board, to receive location information of the target interactive network board in response to the broadcast inquiry, and to establish communication with the target interactive network board. The MAC address is downloaded to a RAM on the board, verified therein, and loaded into the EPROM from the RAM.

Pre-allocation media access control protocols for multiple access WDM photonic networks

Abstract: Media access control protocols for an optically interconnected star-coupled system with pre-allocated WDMA channels are introduced and compared. The photonic network is based on a passive star-coupled WDM–based configuration with high topological connectivity and low complexity. The channels are pre-allocated to the nodes with this approach, where each node has a home channel that it uses either for all data packet transmissions or all data packet receptions. A home channel may be shared if the number of nodes exceeds the number of channels in the system. This approach does not require both tunable transmitters and tunable receivers. The performance of a generalized random access protocol is compared to a protocol based on interleaved time multiplexing. Both protocols are designed to operate in a multiple-channel multiple-access environment and require each node to possess a tunable transmitter and a fixed (or slow tunable) receiver. Semi-markov analytic models are developed to investigate the performance of the two protocols. The analytic models are validated through simulation and performance is evaluated in terms of network throughput and packet delay with variations in system parameters.

Third generation wireless information networks

Abstract: 1. Developments in Wireless Communications - Navigating the Regulatory Morass.- 2. Why do We Need Standards for Mobile/Wireless Communications.- 3. Standards for Global Personal Communications Services.- 4. WIN with OSI.- 5. Trellis Coding for Full-Response CPM.- 6. Design Considerations for a Future Portable Multimedia Terminal.- 7. Dynamic Resource Acquisition: Distributed Carrier Allocation for Tdma Cellular Systems.- 8. On Dynamic Channel Allocation in Cellular/Wireless Networks.- 9. A Radio-Local Area Network with Efficient Resource Allocation.- 10. Radio Channel Control for a Multi-Carrier TDMA Microcell System.- 11. Models for Call Hand-Off Schemes in Cellular Communication Networks.- 12. Handoff in Microcellular Based Personal Telephone Systems.- 13. Sip Simulation for Urban Microcells.- 14. Evaluation of VTS CSMA for Media Access Control in Land Mobile Data Communication.- 15. Analytical Performance Evaluation of the R-BTMA Mac Protocol.- 16. A Multiple Access Technique for Radio-Local Area Networks.- 17. Spread Spectrum Wireless Information Networks for the Small Office.- 18. An Overview of Code Division Multiple Access (CDMA) Applied to the Design of Personal Communications Networks.- 19. CDMA Power Control for Wireless Networks.

A queueing model for a data station within the IEEE 802.6 MAN

Abstract: An exact queuing model for a station that operates within the IEEE 802.6 subnetwork of a metropolitan area network (MAN) is developed. The model reflects the station's perception of the subnetwork and it has been developed by mapping the media access control (MAC) protocol to a queuing service discipline. The model is a discrete-time single-server queue with two classes of customers served according to a quasi-gated discipline. The one class of customers represents the data packets generated by the station, while the other class represents the requests registered by the station. The model gives useful insight into the operation of the station and it can be used as a cornerstone module for analytical and/or simulation models of the whole IEEE 802.6 subnetwork. >

CDMA versus dynamic TDMA for access control in an integrated voice/data PCN

Abstract: The authors present a comparative evaluation of dynamic TDMA and spread spectrum CDMA approaches to medium access control (MAC) in an integrated voice/data PCN environment After a brief discussion of general technological issues related to the selection of a MAC approach for PCN, dynamic TDMA and packet CDMA protocols appropriate for the support of integrated voice/data traffic are described Performance evaluation methodologies for determining the system capacities of these competing MAC techniques are described System-level performance measures such as channel utilization, voice blocking probability and data delay are obtained from a detailed simulation model for the D-TDMA case, and compared with a preliminary set of corresponding results for asynchronous packet CDMA Overall, the results show that while CDMA does achieve a higher normalized capacity than TDMA, the gains are very sensitive to the propagation loss constant, and must be balanced against higher message transfer delay for certain data services >

Timed Ethernet: Real-Time Formal Specification of Ethernet

Abstract: The goal of this paper is to show how formal specification can be applied to a full-fledged, real-world protocol while maintaining, or even enhancing, readability. The system we formally specify is Ethernet as it appears in IEEE 802.3. We focus on the specification of the Medium Access Control (MAC) layer—the part of the Data Link Layer that implements a 1-persistent CSMA/CD protocol — and its interfaces with adjacent layers. The specification method is based on one of Henzinger's real-time models. We believe that the readability of our specification is due to the graphical presentation using transition graphs of real-time programs.

The IBM 8209 LAN bridge

Abstract: The issues involved in bridging 802.5 (token-ring) and 802.3 (Ethernet) networks at the media access control (MAC) layer are discussed. The issues concern incompatibilities between the two networks in six areas: routing schemes, station addresses, frame formats, and local area network speeds. An approach incorporated in the IBM 8209 LAN bridge for resolving the incompatibilities is described. The IBM 8209 LAN bridge, a two-port MAC bridge, supports source routing on the token ring/802.5 side and transparent bridging on the Ethernet/802.3 side. Recently proposed changes in the token-ring source routing standards are discussed. >

Performance analysis and simulation of vehicle-beacon communications protocols

Abstract: Due to relatively short communication zones, the data link protocols being developed or proposed for vehicle-beacon communications must be carefully evaluated by analysis and simulation, taking antenna configurations, geometry, propagation, and channel characteristics into account. Different methods for media access control and recovering algorithms after message collision are presented and evaluated. Based on the results from analysis and simulation the optimal system parameters and dimensions can be determined. In addition, it is possible to estimate whether not only a single application (e.g., automatic debiting) but several other RTI applications (e.g., route guidance, parking management, etc.) can be supported by a multiservice beacon. >

Status sense multiple-access (S/sup 2/MA) communication

Abstract: A new contention-based multi-access protocol, named status sense multiple access (S/sup 2/MA), is introduced. S/sup 2/MA is synchronous TDMA in its framing but it possesses many features of random access. The approach of S/sup 2/MA is geared towards integrating heterogeneous classes of customers over a common broadcast channel. The performance of this protocol with two classes of customers, such as voice and data, is analyzed. Unlike fixed and some moveable-boundary approaches of integrating voice and data, here no slot is wasted, except for possible collision, as long as there is a demand for the slot from either of the two classes. Therefore, the channel utilization efficiency can be very high. >

Wavelength-division multiple access network based on centralized common-wavelength control

Abstract: In wavelength-division multiple access (WDMA) networks, many high-speed connections over different wavelengths allow vast aggregate throughput without the limitations posed by serial electronic processing of the data. Most WDMA networks are based on dynamic tuning of the transmitted or received wavelengths, hence an effective control of the multiple-wavelength traffic is of key importance. Recently proposed WDMA control protocols include the use of a tunable filter to poll through the transmitter wavelengths for setup requests directed to itself and the use of a common wavelength dedicated to control signaling.2,3

A performance comparison of ALOHA-reservation and PRMA in integrated voice and data wireless local area networks

Abstract: Reservation media access control (MAC) protocols for integrated voice and data wireless LANs are studied. Simulation is used to compare the performance of two reservation protocols: ALOHA-reservation and packet reservation multiple access (PRMA). Emphasis is placed on the maximum number of terminals that the system can support within given values of the voice packet dropping probability and average data delay. Results show that the difference in the maximum number between the two protocols is small. It is seen that if data messages are long and if the number of terminals is not so large, the average data delay of ALOHA-reservation is smaller than that of PRMA. >

A scheme for remote LAN bridging across SMDS MANs

Abstract: A remote bridging scheme for the interconnection of local area networks (LANs) across cell-based public metropolitan area networks (MANs), such as SMDS (switched megabit data service) networks, is briefly described. The scheme makes use of some characteristics of cell-based networks such as the hierarchical E.164 addressing scheme, which makes routing at the MAC level through the public environment possible. This leads to a less complex and more efficient bridging scheme called open bridging. In contrast with standard media access control (MAC) bridging approaches, open bridging emphasizes the notion of independent domains to reflect the practical aspects of interconnecting unrelated private bridged LANs across a public network. Each domain is allowed to independently manage and operate its internal connectivity. Full support for current bridging standards is provided within each domain. >

Information processing terminal for radio communication network

Abstract: PURPOSE:To obtain the information processing terminal for a radio communication network enabling CSMA/CD and improving throughput by providing a signal collision deciding means or the like to decide signal collision when test signals excepting for test signals transmitted by a test signal transmitting means are received within a second period including a first period. CONSTITUTION:The above terminal is composed of a high frequency part as a physical layer and a data processing part being a MAC(media access control) layer. Further, the high frequency part is composed of a non-directional antenna 100, circulator 101, reception system 200 and transmission system 300. When transmitting communication data from the information processing terminal, the test signals are transmitted to a prescribed band during a test signal transmission period before this communication data transmission and when any test signals excepting for the transmitted test signals are received within a pulse number check period, the signal collision is decided.

Performance analysis of the FDDI MAC protocol

Abstract: The fiber distributed data interface (FDDI) media access control (MAC) mechanism supports two classes of traffic: synchronous and asynchronous. The asynchronous traffic can further be divided into eight subclasses according to priority. The FDDI performance is closely related to its operational parameters, such as the number of stations on the ring, the frame size, and the target token rotation time (TTRT). The authors analyse the delay and throughput of the FDDI MAC protocol while both the synchronous and eight asynchronous traffic types are present. A simulation model based on the M/D/1 queuing system is developed. Two configurations of 45 and 100 stations, respectively, have been studied. From the simulation results, several operational guidelines for setting TTRT are proposed. A delay prediction procedure is developed by incorporating Lagrange's form of the interpolating polynomial. It can predict the main frame delay within 2.5% of the simulation value. The prediction procedure in conjunction with operational guidelines provides an effective tool for tuning the FDDI network. >

FairQDB: a new simple and optimal access mechanism for dual bus networks

Abstract: The authors present a new access control scheme for dual bus networks which is absolutely fair in bandwidth sharing and can replace the DQDB access protocol without changes in the transmission system apart from the protocol machine. The mechanism retains all the positive features of DQDB including simplicity, robustness, flexibility, 100% bandwidth utilization and zero access delay at very low load. In addition, it can be set to provide a bandwidth sharing pattern that is different from a uniform one, as may be the case if bridges or other large users are present, and priorities can be easily superimposed. >

An integrated video/voice/data protocol using distributed priority change

Abstract: As a media access control (MAC) protocol for integrated services on a high-speed LAN, the distributed priority change (DPC) protocol is proposed. DPC supports synchronous voice/video service and asynchronous data service. To support synchronous service, it is necessary to guarantee periodic access to the network with a small delay variation. This requirement is met by alternating between the synchronous mode and the asynchronous mode. In DPC, there is not central controller and there is no special bit in the token for reservation to realize fair asynchronous data transmission. Performance comparisons with other token ring protocols are presented. It is shown that DPC can achieve higher maximum throughput than other priority protocols using a central controller. DPC can transmit long size data more effectively than the timed token protocol used in FDDI. >

A class of MAC protocols for sharing ATM local access PONs

Abstract: The cost of a dedicated fiber access to the B-ISDN is too high for small business and residential customers, necessitating some form of resource sharing. Combining ATM over a passive optical network (APON) with a suitable medium access control (MAC) protocol can provide significant cost savings and a reasonable bandwidth. In this way, this customer section can also enjoy introduction of broadband services at a relatively early stage. The emphasis of the MAC protocol presented is placed on service transparency with an aim to incur minimal changes to the local exchange (LEX) when an APON is attached. Sharing is effected by a reservation-based time division multiple access method. >

Fiber optic backbone boosts local-area networks

Abstract: The evolving Fiber Distributed Data Interface (FDDI) for fiber optic networks, which greatly increases system capacity and flexibility, is discussed. The standard is described in terms of the ISO's Open Systems Interconnection (OSI) reference model. The initial FDDI standard defines four protocols: physical layer medium dependent, physical layer, media access control, and station management. Each of these is examined. Optical technology and the use of application-specific integrated circuits required by FDDI are discussed. Applications of FDDI and its future evolution are considered. >

Media access protocols for high speed data bus-a simulation study

Abstract: The authors discuss a high-speed data bus for satellite (HSDB-S) architecture and evaluate media access control (MAC) protocols. They simulated the fiber distributed data interface (FDDI) protocol, which is applicable to HSDB, for asynchronous and synchronous traffic in terms of throughput, delay, queue length, and station latency. They propose a deferred priority protocol and compare throughput-delay performance with preemptive priority and normal (FDDI) priority protocols. The deferred priority protocol is shown to provide better throughput than the preemptive priority protocol, but results in less delay performance for highest-priority messages. For lowest-priority traffic, the preemptive priority protocol provides the least throughput, and the worst delay performance. >

Positioning routing in the protocol stack (or 'passing the bus-selection buck')

Abstract: It is proposed that the distributed queue dual bus (DQDB) medium access control (MAC) layer, which utilizes the services of dual unidirectional physical layer links, can be considered as providing access to dual unidirectional networks, rather than a single bidirectional network as alluded to in the IEEE 802.6 MAN standard. With the latter approach, the MAC layer may need to perform bus selection, whereas this is performed by higher layers in the former approach. The pros and cons of locating link selection in various positions of the protocol stack are examined. >

Adaptation of FDDI physical layer chip to Playthrough protocol

Abstract: Data flow design and very-high-speed integrated circuit (VHSIC) hardware description language (VHDL) behavioral simulation are presented for a physical layer encoder/decoder (ENDEC) chip that supports use of a Playthrough protocol on ring topology local area networks. The authors describe the Playthrough protocol's operational concept. The ENDEC design uses as much of the fiber distributed data interface (FDDI) standard as possible to support a 100-Mb/s data transfer rate on fiber-optic media with a chip that is plug compatible with the Advanced Micro Devices (AMD) FDDI ENDEC chip. The design uses an adaptation of the AMD FDDI ENDEC data flow structure; however, because the Playthrough media access control (MAC) protocol differs from FDDI's, a new control flow structure and a different internal structure are required to accommodate Playthrough MAC (PMAC) chip functions. >

A simple, effective media access protocol system for integrated, high data rate networks

Abstract: The operation and performance of a dual media access protocol for integrated, gigabit networks are described. Unlike other dual protocols, each protocol supports a different class of traffic. The Carrier Sensed Multiple Access-Ring Network (CSMA/RN) protocol and the Circulating Reservation Packet (CRP) protocol support asynchronous and synchronous traffic, respectively. The two protocols operate with minimal impact upon each other. Performance information demonstrates that they support a complete range of integrated traffic loads, do not require call setup/termination or a special node for synchronous traffic control, and provide effective pre-use and recovery. The CRP also provides guaranteed access and fairness control for the asynchronous system. The paper demonstrates that the CSMA-CRP system fulfills many of the requirements for gigabit LAN-MAN networks most effectively and simply. To accomplish this, CSMA-CRP features are compared against similar ring and bus systems, such as Cambridge Fast Ring, Metaring, Cyclic Reservation Multiple Access, and Distributed Dual Queue Data Bus (DQDB).

A Realistic Approach to Analyzing Performance of the Ethernet based on the Space-Time Model

Abstract: A very popular access control method for local area networks having the bus topology is the carrier sense multiple access with collision detection (CSMA/CD) protocol because of its simplicity. This protocol can provide high throughput if the signal propagation time plus carrier detection delay is much smaller than the packet transmission time. Therefore, it is very crutial for performance analysis to consider both the exact timing of a sequence of the events at individual stations and their positions on the network. A study of the CSMA/CD protocol on the basis of space-time model which describes not only times of events but also spatial location is analyzed. A simulation study of the Ethernet operation is presented. First, the throughput of the protocol are monitored at the several different observation points on the bus. Second, the effect of packet length is examined. Then these realistic simulation results based on the space-time model are compared to previous time domain results. These results show that the throughput is much higher than time domain results.

Dynamic priority assignment scheme for real-time communications in DQDB networks

Abstract: The authors propose a dynamic priority assignment scheme which is able to make the best use of the multiple priority mechanism and achieve significant system performance for real-time communications. First, they briefly introduce the distributed queue dual bus (DQDB) standard and point out some problems for real-time communications. A dynamic system model is proposed and some design strategies for the dynamic priority scheme are discussed. An efficient assignment algorithm based on the analysis of the mean media access delay is presented. Simulation results under various situations validated the model analysis and showed the significant performance improvement, compared to conventional media access control (MAC) protocols, for real-time communications. >

DFIFO protocol and analysis

Abstract: To meet the challenge of future communication requirements, the authors explore protocols for communication networks at data rates of 1 to 10 Gb/s, called gigabit networks. In particular, a new protocol, referred to as the distributed first in first out (DFIFO) protocol, is presented. The objectives of this new protocol are to enhance network throughput and reduce media access control (MAC) delay to meet the requirements of gigabit networks. The key concept of the DFIFO protocol is the global time stamp (GTS) scheme, which provides a global timing reference so that data segments in the entire network are ordered in a FIFO manner. By using the destination removal policy, DFIFO is able to use the network bandwidth effectively. The DFIFO protocol simulation model results are provided. >

Evaluation of VTS CSMA for media access control in land mobile data communication

Abstract: In land mobile data communication networks the Media Access Control facility regulates mobile data terminal access to the radio channel. In selecting the mobile radio channel access protocol, the emphasis should be placed on fair access for packet transmission among the mobile data terminals, with the objective of maximizing the throughput-delay performance. Given the severity of the noise characteristics for the mobile radio channel, the access protocol must provide a consistent high level of performance despite the inherent unreliability of data transmission. And, finally, due to the processing and memory limitations of a cost effective mobile data terminal, the access protocol must also be relatively simple to implement.

A framework for specifying a physical layer and medium for wireless local area networks

Abstract: A conceptual framework for specifying a physical layer and a medium for a wireless local area network is detailed. This framework defines a physical layer entity consisting of a medium independent sublayer, a physical convergence sublayer and a medium dependent sublayer. The action of this physical layer entity is to provide a bidirectional mapping between the information present at the media access control interface and the information present at the media interface. The framework defines a medium characterization methodology that can be used to specify specific instances of medium for use in conformance testing and installation planning. In order to illustrate the use of such a framework a direct sequence spread spectrum PHY-layer entity and some thoughts on the characterization of the 25 GHz ISM band medium are provided. This example is not intended as an actual proposal of a standard. Rather, it is intended strictly to illustrate the operation of the template. >