- Email: [email protected]
Ring technology local area networks
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Conference Reports
Ring Technology Local Area Networks A Workshop on Ring Technology based Local Area Networks was held September 28-30, 1983 in Kent, U.K. The workshop was organized by IFIP WG 6.4 and the University of Kent Computing Laboratory. The workshop provided an in-depth forum for developers and researchers in the field of Local Area Network Ring Technology. Attendance at the workshop was limited to 65, and all attendees were asked to contribute to the working sessions. The program contained lectures covering all the main types of ring network, servers attached to these networks, and other related topics. Lectures ranged from addressing matters and reliability enhancements, to network modelling and more formal, theoretical approaches to rings. In addition to the submitted lectures, there were a number of short reports given by invited speakers. These include details of a panel discussion, which provided a lively interchange of ideas and views between the audience and a panel of experts.
basic ring access protocols and a CSMA/CD bus access protocol.
Multilink Multilink is a register-insertion ring using a self-clocked NRZ data format over twisted-pair cable. J.S. Grant (Nine Tiles Computer Systems, Ltd., U.K.) explained that its main use is for connecting individual terminals, workstations, printers, etc. to each other and to central computing and communications facilities. An LSI version has been developed which is particularly suitable for interfacing to microcomputers. In a lecture entitled "Multilink - A Ring That Provides a Simple Interface for Individual Outstations", Grant described the design of the network and its role in distributed information processing systems.
Bath Token Ring Ring Networks M.T. Liu (Ohio State University, U.S.A.) and D.M. Rouse (Bell Laboratories, Ohio, U.S.A.) pre-
sented a study of ten representative ring networks developed during the past 14 years by research laboratories, industry and universities. The networks selected for study were the Newhall ring, the Pierce ring, the Hafner ring, the Burroughs ring, Prime's Ringnet, the IBM Zurich ring, DCS, the Cambridge rings, D L C N / D D L C N and TORNET. The study considered data rates, transmission media, topologies, channel access protocols, ring synchronization, ring supervision, and network applications. Liu and Rouse also discussed reliability and maintenance issues. They further made a performance evaluation between the three North-Holland Computer Networks 8 (1984) 133-155
The design of all major aspects of a particular token ring was described by P.J. Willis (University of Bath, U.K.). The implementation, he noted, is at a stage where some raw performance figures are now obtainable and the first use is being made of the network. Willis did not confine his presentation to purely technical matters but also mentioned some of the more mundane considerations which influenced the development of the design. The lecture was entitled "The Bath Token Ring: Architecture and Early Experience".
Train Ring Network Network controllers built around programmable data link control chips facilitate implementation of local network protocols. A. Michalski and R. Lis (Polish Academy of Sciences, Warsaw) de-
134
Conference Reports
scribed a microcomputer communication system called Train Ring Network, which has a tokenpassing architecture with centralized control. The logical connections between stations are based on decentralized virtual channel service. Stop-andwait acknowledgement scheme and time-out mechanism are used in the system.
TAMNET L. Sintonen (Tampere University of Technology, Finland) described a local computer network (TAMNET) implemented at the Electronics Laboratory of Tampere University of Technology for experimental purposes. The network topology is a ring operating at a bit rate of 2 Mbit/s maximum. Peripheral devices are connected to the network by microprocessor-based network nodes which provide link-level network services. The network operating system is distributed among these stations. Sintonen discussed the design and implementation of the high-level protocols for file transfer and process-to-process communication.
Cambridge Fast Ring The Cambridge Fast Ring (CFR) is a high speed local area network similar in principle to the well established Cambridge Ring. S. Temple (University of Cambridge Computer Laboratory, U.K.) explained that in addition to allowing much higher transfer rates than existing networks, the CFR incorporates facilities for partitioning the bandwidth between several groups of users and for connecting rings together without the need for bridge computers and complex addressing schemes. The CFR is currently being implemented in VLSI. Temple described the major design decisions that were taken and the system which resulted from them.
mb/sec token ring. This ring was designed specifically for the distributed processing environment. Distributed processing implies a large number of computers, fifty or more, which cooperate in the solution of analysis or simulation problems. The main areas of focus in the design decisions were the encoding scheme and synchronization method. Choices other than those typical for slower systems proved to be optimal for the higher speed network.
Addressing and Routing A possible solution to the problems of addressing and routing in a local network based on token rings was discussed by P.A. Janson and E. Mumprecht (IBM Zurich Research Laboratory, Switzerland). First, the routing function should avoid the use of any routing table. Second, addresses are to be allocated to stations automatically and dynamically over the network avoiding the need to manage unique addresses on a world-wide basis. Third, it should be possible to partition and replicate the tables keeping track of name-toaddress mappings. Janson and Mumprecht explained how these objectives are attained. They also discussed the potential advantages of the scheme and suggested possible alternatives for further investigation.
Distributed Approach to Loading J. Crowcroft and R. Hall (University College London, U.K.) described a unified flexible approach to bootstrapping and loading systems in a distributed computing environment. The emphasis was on combining automatic and manual methods of reloading computers where the integrity of services must be maintained. At the same time, development must be supported. The lecture was entitled "A Distributed Approach to Loading in a Networked Environment".
High Speed Token Passing Ring The token ring Local Area Networking approach is particularly suited to high speed LAN applications, according to N. Salwen and H. Salwen (Proteon, Mass., U.S.A.). Salwen and Salwen described the design trade-offs considered for an 80
Distributed System Management According to S.R. Wilbur (University College London, U.K.), large local area network systems have similar management requirements to those of
Conference Reports
conventional wide area networks. Distributed systems using the client-server model pose some additional problems, Wilbur noted, since many more services are provided. Wilbur explored in his presentation some aspects of managing such distributed systems, based heavily on the experiences being gained in using the Universe network of Cambridge Rings and Satellite Links. The specific management issues addressed were monitoring, tracing of calls, route management and name management.
Optical Token Loop H. Hatta and K. Yasue (NEC Corp., Tokyo, Japan) described technical considerations, design choices, implementations and some evaluations on a local area network developed by NEC Corporation. They explained that optical fiber technology and token passing technique are employed in this loop (ring) network, achieving a reliable, efficient and flexible communication medium. This local area network, called C&C-NET LOOP 6770, has been installed and is operating on several customer premises.
Major and Minor Ring Architecture
135
munication network. In a lecture entitled "The Application of Optical Fibers to Local Area Ring Networks", P.A. Davies and F.A. Ghani (University of Kent, U.K.) considered the use of fiber optics in the Local Area Network environment. In particular, they examined the advantages and disadvantages of using optical fiber in a ring network.
Enhancing Reliability One of the major criticisms of ring, or loop, topologies for LANs is the vulnerability of the network to failure of the cable or the catastrophic failure of a node. For many applications faulttolerance must be added to bring the estimated reliability up to an acceptable level. R.M. Falconer (British Telecom Research Laboratories, U.K.) considered the benefits of four common reliability enhancement techniques. Markov models were constructued, taking due account of the finite probabilities of common-mode cable failures and the limitations on fault-detector efficacy. Falconer evaluated the models numerically and demonstrated the relative sensitivities of the techniques to changing failure rates.
Voice and Data Traffic
R. Yatsuboshi and A. Takeyama (Fujitsu Laboratories Ltd., Japan) described a new local area network using fiber optics and emphasized the design philosophy, choice of design parameters and network system applications. FACOM 2880 optical data highway is a new general purpose LAN with ring topology. It is composed of two types of data highway based on the same design architecture. The minor ring (FACOM 2881) is designed to accommodate up to 240 terminals using 4.096Mb/s optical fiber highway. The major ring (RACOM 2883) accommodates up to 4096 terminals by 32.768Mb/s highway. According to Yatsuboshi and Takeyama, the combination of major and minor rings can meet various user requirements providing a variety of system configurations.
Recent developments in LANs raise the question of the provision of voice and data services on them, in order to provide both computer and telephone communication support to organizations utilizing such networks. To this end, several high bandwidths LANS have been proposed over the past few years using baseband, broadband and PBX technologies. B. Chaillet, J.P. Cabanel and D. Sazbon (Universit6 Paul Sabatier, Toulouse, France) used a formal approach to analyze several problems relating to voice/data traffic in baseband LANs, bearing in mind that the most important constraints are imposed by real time voice communication. They presented a technique for dealing with the synchronous circuits used for voice traffic.
Optical Fibers
NPL Multicomputer Ring
Optical fiber can provide a wideband channel suitable for use in a high bit rate computer corn-
Y. Paker, H. English and M. Bozyigit (The Polytechnic of Central London, U.K.) described
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ConferenceReports
the simulation package written for the NPL Multicomputer ring. This was an extension to the Micross package developed at the Polytechnic of Central London. Using this package, extensive runs have been performed to simulate the NPL Multicomputer ring under vastly varying conditions to evaluate its performance. A set of experiments has been carried out for a specific configuration of the ring as implemented by NPL. Paker, English and Bozyigit noted that this has allowed validation of simulation results against the real data obtained. Another set of simulation runs has been carried out to evaluate the influence of the reserved function.
JNT-ringPAD The logical architecture of the JNT-ringPAD was described by N.V. Toy (CAMTEC Electronics Ltd., U.K.). Included in the lecture was a description of the planned progression to other related Local Area Network products. The JNT-PAD is a 16-channel X.25 Terminal Concentrator which was designed as part of a contract for the Joint Network Team. It was conceived around the Z80 microprocessor and a standard back-plane bus the MOSTEK SDB, using double-height Eurocard mechanics.
Typesetting Server DMA Interface and Terminal Concentrator The primary testbench for the current projects at CSALAB in Stockholm is a number of computers connected to a LAN. Important factors, when selecting the processors, were a large address space and ease of programming. J. Widkn (CSALAB, Stockholm, Sweden) pointed out that as the MC68000 satisfied these and other requirements, it was decided to connect a number of MC68000 based computers to their Cambridge ring. There were no ring interfaces commercially available for any MC68000 systems and the interfaces for other computers were rather slow. It was therefore decided to design an interface on their own. Widbn explained that it turned out that their requirements of modularity made it easy to redesign the interface into a terminal concentrator for the ring.
High Performance Concentrator A Zilog Z80 based concentrator has been built and interfaced to the Cambridge Ring. R.J. Loader and P.A. Martin (University of Reading, U.K.) investigated the performance of the Z80 CPU and ring interface as a protocol engine for CR82 protocols as a function of CPU speed, data packet size and number of ports. The design of the RS232 and ring interfaces exploits DMA and also minimizes the rate of generation of interrupts. According to Loader and Martin, these hardware features allow a high degree of parallelism between protocol layers leading to good performance.
The University of Kent has based all its main computing facilities on a Cambridge ring since the beginning of 1980. Many of these facilities are now being moved off the main time-sharing hosts onto dedicated servers on the ring. LA. Utting, D.J. Caul, H. Brown and S.E. Binns (University of Kent, U.K.) described the setting up of the first stage of a typesetting server to provide high quality document preparation and printing services for the Cambridge ring. In addition, they identified the areas where the existing ring protocols and services are helpful and where they are inadequate.
Ring Developments at Kent University E.B. Spratt (University of Kent, U.K.) provided a short overview of some of the developments in a Ring based LAN which have taken place at the University of Kent Computing Laboratory over the past five years, together with an indication of future plans. Since the original set-up in 1979, the local network, now known as UKCNET, has grown by an overall factor of at least five, and now extends to almost all the main buildings on the University campus. Spratt described its present state in two ways: firstly, a user view and secondly, a systems view. He emphasized that the services on a network are, in the final analysis, the only real justification for its existence.
IEEE Project 802 Activities A "Report on IEEE Project 802 Activities" was presented at the workshop by J. Rance (Racal-
Conference Reports Milgo Ltd., U.K.). The adoption of Ring technology for LANs at Kent, concluded Rance, has been an effective choice and U K C N E T is the only high speed local area network in full operation at a UK University which is used as a central university service for teaching, research and administration. One important property of ring networks is that they can be scaled up in size. Industrial Panel Discussion This panel discussion on networks and communications ranged over several related issues with lively participation from the audience. The focus of interest was future development in the field of networks and communications, with special reference to the type of networks we are likely to see in the future, the areas in which communications networks will be used and the standards that will prevail. The Panel Discussion was reported by U. Fuller and Z.P. Kemp (University of Kent, U.K.).
Future of Ring Developments R. Needham (Cambridge University, U.K.) made some comments on the functionality and usability of the current generation of Rings which can be taken as pointers to future developments. At the moment, Needham observed, there is a tendency to use a Ring for a particular application not because of its suitability but because of its availability and despite the needs of such applica-
137
tions for differing network designs or standards. However, he said, because of the costs and delays involved in the economically necessary implementation of network designs in silicon, the requirement is for few, but multi-functional, designs. Different applications make different demands on a network and require different degrees of standardization, but Rings do have certain advantages over other network architectures: (1) point-to-point length, (2) speed, and (3) bandwidth sharing. Needham looked at various developments in terms of their exploitation of these features and examined how they caused different attitudes to questions of protocols and, hence, standardization.
LAN Protocols and ISO OSI Model This Working Session was a combination of two sessions, one on local area network protocols, the other on the role of the ISO Open System Interconnection Model in LANs. The results of the lively discussion were summarized in a report by the Chairman of the Session, A. Danthine (University of Liege, Belgium). The Proceedings of this conference have been edited by I. Dallas and E.B. Spratt and published by North-Holland under the title "Ring Technology Local Area Networks". 1984. x + 270 pages. ISBN 0-444-86852. Price: US $36.50 (USA/Canada), Dfl.85.00 (rest of the world).
IFIP '83 - 9th World Computer Congress IFIP '83, the 9th World Computer Congress, was held in Paris, France from September 19-23, 1983. The Congress offered a very comprehensive scientific program with 40 Invited Lectures, 98 Technical Papers from 21 countries and 32 Panel Discussions with experts from all spheres of the computer field. Also at the Congress was a comprehensive exhibition of techniques and equipment as well as a videotex service to inform instantly of all the events of the congress.
The IFIP Congress '83 Program Committee, chaired by D.C. Tsichritzis, organized a technical program which allowed participants to obtain a broad view of developments in the informatics field and also to examine in detail the latest developments in specialized areas. The Program was separated into ten areas which provide a focal point for reviewing research and development activity in the informatics field. Each Invited or Submitted Lecture, and each Panel Discussion, was loosely identified
Conference Reports
Ring Technology Local Area Networks A Workshop on Ring Technology based Local Area Networks was held September 28-30, 1983 in Kent, U.K. The workshop was organized by IFIP WG 6.4 and the University of Kent Computing Laboratory. The workshop provided an in-depth forum for developers and researchers in the field of Local Area Network Ring Technology. Attendance at the workshop was limited to 65, and all attendees were asked to contribute to the working sessions. The program contained lectures covering all the main types of ring network, servers attached to these networks, and other related topics. Lectures ranged from addressing matters and reliability enhancements, to network modelling and more formal, theoretical approaches to rings. In addition to the submitted lectures, there were a number of short reports given by invited speakers. These include details of a panel discussion, which provided a lively interchange of ideas and views between the audience and a panel of experts.
basic ring access protocols and a CSMA/CD bus access protocol.
Multilink Multilink is a register-insertion ring using a self-clocked NRZ data format over twisted-pair cable. J.S. Grant (Nine Tiles Computer Systems, Ltd., U.K.) explained that its main use is for connecting individual terminals, workstations, printers, etc. to each other and to central computing and communications facilities. An LSI version has been developed which is particularly suitable for interfacing to microcomputers. In a lecture entitled "Multilink - A Ring That Provides a Simple Interface for Individual Outstations", Grant described the design of the network and its role in distributed information processing systems.
Bath Token Ring Ring Networks M.T. Liu (Ohio State University, U.S.A.) and D.M. Rouse (Bell Laboratories, Ohio, U.S.A.) pre-
sented a study of ten representative ring networks developed during the past 14 years by research laboratories, industry and universities. The networks selected for study were the Newhall ring, the Pierce ring, the Hafner ring, the Burroughs ring, Prime's Ringnet, the IBM Zurich ring, DCS, the Cambridge rings, D L C N / D D L C N and TORNET. The study considered data rates, transmission media, topologies, channel access protocols, ring synchronization, ring supervision, and network applications. Liu and Rouse also discussed reliability and maintenance issues. They further made a performance evaluation between the three North-Holland Computer Networks 8 (1984) 133-155
The design of all major aspects of a particular token ring was described by P.J. Willis (University of Bath, U.K.). The implementation, he noted, is at a stage where some raw performance figures are now obtainable and the first use is being made of the network. Willis did not confine his presentation to purely technical matters but also mentioned some of the more mundane considerations which influenced the development of the design. The lecture was entitled "The Bath Token Ring: Architecture and Early Experience".
Train Ring Network Network controllers built around programmable data link control chips facilitate implementation of local network protocols. A. Michalski and R. Lis (Polish Academy of Sciences, Warsaw) de-
134
Conference Reports
scribed a microcomputer communication system called Train Ring Network, which has a tokenpassing architecture with centralized control. The logical connections between stations are based on decentralized virtual channel service. Stop-andwait acknowledgement scheme and time-out mechanism are used in the system.
TAMNET L. Sintonen (Tampere University of Technology, Finland) described a local computer network (TAMNET) implemented at the Electronics Laboratory of Tampere University of Technology for experimental purposes. The network topology is a ring operating at a bit rate of 2 Mbit/s maximum. Peripheral devices are connected to the network by microprocessor-based network nodes which provide link-level network services. The network operating system is distributed among these stations. Sintonen discussed the design and implementation of the high-level protocols for file transfer and process-to-process communication.
Cambridge Fast Ring The Cambridge Fast Ring (CFR) is a high speed local area network similar in principle to the well established Cambridge Ring. S. Temple (University of Cambridge Computer Laboratory, U.K.) explained that in addition to allowing much higher transfer rates than existing networks, the CFR incorporates facilities for partitioning the bandwidth between several groups of users and for connecting rings together without the need for bridge computers and complex addressing schemes. The CFR is currently being implemented in VLSI. Temple described the major design decisions that were taken and the system which resulted from them.
mb/sec token ring. This ring was designed specifically for the distributed processing environment. Distributed processing implies a large number of computers, fifty or more, which cooperate in the solution of analysis or simulation problems. The main areas of focus in the design decisions were the encoding scheme and synchronization method. Choices other than those typical for slower systems proved to be optimal for the higher speed network.
Addressing and Routing A possible solution to the problems of addressing and routing in a local network based on token rings was discussed by P.A. Janson and E. Mumprecht (IBM Zurich Research Laboratory, Switzerland). First, the routing function should avoid the use of any routing table. Second, addresses are to be allocated to stations automatically and dynamically over the network avoiding the need to manage unique addresses on a world-wide basis. Third, it should be possible to partition and replicate the tables keeping track of name-toaddress mappings. Janson and Mumprecht explained how these objectives are attained. They also discussed the potential advantages of the scheme and suggested possible alternatives for further investigation.
Distributed Approach to Loading J. Crowcroft and R. Hall (University College London, U.K.) described a unified flexible approach to bootstrapping and loading systems in a distributed computing environment. The emphasis was on combining automatic and manual methods of reloading computers where the integrity of services must be maintained. At the same time, development must be supported. The lecture was entitled "A Distributed Approach to Loading in a Networked Environment".
High Speed Token Passing Ring The token ring Local Area Networking approach is particularly suited to high speed LAN applications, according to N. Salwen and H. Salwen (Proteon, Mass., U.S.A.). Salwen and Salwen described the design trade-offs considered for an 80
Distributed System Management According to S.R. Wilbur (University College London, U.K.), large local area network systems have similar management requirements to those of
Conference Reports
conventional wide area networks. Distributed systems using the client-server model pose some additional problems, Wilbur noted, since many more services are provided. Wilbur explored in his presentation some aspects of managing such distributed systems, based heavily on the experiences being gained in using the Universe network of Cambridge Rings and Satellite Links. The specific management issues addressed were monitoring, tracing of calls, route management and name management.
Optical Token Loop H. Hatta and K. Yasue (NEC Corp., Tokyo, Japan) described technical considerations, design choices, implementations and some evaluations on a local area network developed by NEC Corporation. They explained that optical fiber technology and token passing technique are employed in this loop (ring) network, achieving a reliable, efficient and flexible communication medium. This local area network, called C&C-NET LOOP 6770, has been installed and is operating on several customer premises.
Major and Minor Ring Architecture
135
munication network. In a lecture entitled "The Application of Optical Fibers to Local Area Ring Networks", P.A. Davies and F.A. Ghani (University of Kent, U.K.) considered the use of fiber optics in the Local Area Network environment. In particular, they examined the advantages and disadvantages of using optical fiber in a ring network.
Enhancing Reliability One of the major criticisms of ring, or loop, topologies for LANs is the vulnerability of the network to failure of the cable or the catastrophic failure of a node. For many applications faulttolerance must be added to bring the estimated reliability up to an acceptable level. R.M. Falconer (British Telecom Research Laboratories, U.K.) considered the benefits of four common reliability enhancement techniques. Markov models were constructued, taking due account of the finite probabilities of common-mode cable failures and the limitations on fault-detector efficacy. Falconer evaluated the models numerically and demonstrated the relative sensitivities of the techniques to changing failure rates.
Voice and Data Traffic
R. Yatsuboshi and A. Takeyama (Fujitsu Laboratories Ltd., Japan) described a new local area network using fiber optics and emphasized the design philosophy, choice of design parameters and network system applications. FACOM 2880 optical data highway is a new general purpose LAN with ring topology. It is composed of two types of data highway based on the same design architecture. The minor ring (FACOM 2881) is designed to accommodate up to 240 terminals using 4.096Mb/s optical fiber highway. The major ring (RACOM 2883) accommodates up to 4096 terminals by 32.768Mb/s highway. According to Yatsuboshi and Takeyama, the combination of major and minor rings can meet various user requirements providing a variety of system configurations.
Recent developments in LANs raise the question of the provision of voice and data services on them, in order to provide both computer and telephone communication support to organizations utilizing such networks. To this end, several high bandwidths LANS have been proposed over the past few years using baseband, broadband and PBX technologies. B. Chaillet, J.P. Cabanel and D. Sazbon (Universit6 Paul Sabatier, Toulouse, France) used a formal approach to analyze several problems relating to voice/data traffic in baseband LANs, bearing in mind that the most important constraints are imposed by real time voice communication. They presented a technique for dealing with the synchronous circuits used for voice traffic.
Optical Fibers
NPL Multicomputer Ring
Optical fiber can provide a wideband channel suitable for use in a high bit rate computer corn-
Y. Paker, H. English and M. Bozyigit (The Polytechnic of Central London, U.K.) described
136
ConferenceReports
the simulation package written for the NPL Multicomputer ring. This was an extension to the Micross package developed at the Polytechnic of Central London. Using this package, extensive runs have been performed to simulate the NPL Multicomputer ring under vastly varying conditions to evaluate its performance. A set of experiments has been carried out for a specific configuration of the ring as implemented by NPL. Paker, English and Bozyigit noted that this has allowed validation of simulation results against the real data obtained. Another set of simulation runs has been carried out to evaluate the influence of the reserved function.
JNT-ringPAD The logical architecture of the JNT-ringPAD was described by N.V. Toy (CAMTEC Electronics Ltd., U.K.). Included in the lecture was a description of the planned progression to other related Local Area Network products. The JNT-PAD is a 16-channel X.25 Terminal Concentrator which was designed as part of a contract for the Joint Network Team. It was conceived around the Z80 microprocessor and a standard back-plane bus the MOSTEK SDB, using double-height Eurocard mechanics.
Typesetting Server DMA Interface and Terminal Concentrator The primary testbench for the current projects at CSALAB in Stockholm is a number of computers connected to a LAN. Important factors, when selecting the processors, were a large address space and ease of programming. J. Widkn (CSALAB, Stockholm, Sweden) pointed out that as the MC68000 satisfied these and other requirements, it was decided to connect a number of MC68000 based computers to their Cambridge ring. There were no ring interfaces commercially available for any MC68000 systems and the interfaces for other computers were rather slow. It was therefore decided to design an interface on their own. Widbn explained that it turned out that their requirements of modularity made it easy to redesign the interface into a terminal concentrator for the ring.
High Performance Concentrator A Zilog Z80 based concentrator has been built and interfaced to the Cambridge Ring. R.J. Loader and P.A. Martin (University of Reading, U.K.) investigated the performance of the Z80 CPU and ring interface as a protocol engine for CR82 protocols as a function of CPU speed, data packet size and number of ports. The design of the RS232 and ring interfaces exploits DMA and also minimizes the rate of generation of interrupts. According to Loader and Martin, these hardware features allow a high degree of parallelism between protocol layers leading to good performance.
The University of Kent has based all its main computing facilities on a Cambridge ring since the beginning of 1980. Many of these facilities are now being moved off the main time-sharing hosts onto dedicated servers on the ring. LA. Utting, D.J. Caul, H. Brown and S.E. Binns (University of Kent, U.K.) described the setting up of the first stage of a typesetting server to provide high quality document preparation and printing services for the Cambridge ring. In addition, they identified the areas where the existing ring protocols and services are helpful and where they are inadequate.
Ring Developments at Kent University E.B. Spratt (University of Kent, U.K.) provided a short overview of some of the developments in a Ring based LAN which have taken place at the University of Kent Computing Laboratory over the past five years, together with an indication of future plans. Since the original set-up in 1979, the local network, now known as UKCNET, has grown by an overall factor of at least five, and now extends to almost all the main buildings on the University campus. Spratt described its present state in two ways: firstly, a user view and secondly, a systems view. He emphasized that the services on a network are, in the final analysis, the only real justification for its existence.
IEEE Project 802 Activities A "Report on IEEE Project 802 Activities" was presented at the workshop by J. Rance (Racal-
Conference Reports Milgo Ltd., U.K.). The adoption of Ring technology for LANs at Kent, concluded Rance, has been an effective choice and U K C N E T is the only high speed local area network in full operation at a UK University which is used as a central university service for teaching, research and administration. One important property of ring networks is that they can be scaled up in size. Industrial Panel Discussion This panel discussion on networks and communications ranged over several related issues with lively participation from the audience. The focus of interest was future development in the field of networks and communications, with special reference to the type of networks we are likely to see in the future, the areas in which communications networks will be used and the standards that will prevail. The Panel Discussion was reported by U. Fuller and Z.P. Kemp (University of Kent, U.K.).
Future of Ring Developments R. Needham (Cambridge University, U.K.) made some comments on the functionality and usability of the current generation of Rings which can be taken as pointers to future developments. At the moment, Needham observed, there is a tendency to use a Ring for a particular application not because of its suitability but because of its availability and despite the needs of such applica-
137
tions for differing network designs or standards. However, he said, because of the costs and delays involved in the economically necessary implementation of network designs in silicon, the requirement is for few, but multi-functional, designs. Different applications make different demands on a network and require different degrees of standardization, but Rings do have certain advantages over other network architectures: (1) point-to-point length, (2) speed, and (3) bandwidth sharing. Needham looked at various developments in terms of their exploitation of these features and examined how they caused different attitudes to questions of protocols and, hence, standardization.
LAN Protocols and ISO OSI Model This Working Session was a combination of two sessions, one on local area network protocols, the other on the role of the ISO Open System Interconnection Model in LANs. The results of the lively discussion were summarized in a report by the Chairman of the Session, A. Danthine (University of Liege, Belgium). The Proceedings of this conference have been edited by I. Dallas and E.B. Spratt and published by North-Holland under the title "Ring Technology Local Area Networks". 1984. x + 270 pages. ISBN 0-444-86852. Price: US $36.50 (USA/Canada), Dfl.85.00 (rest of the world).
IFIP '83 - 9th World Computer Congress IFIP '83, the 9th World Computer Congress, was held in Paris, France from September 19-23, 1983. The Congress offered a very comprehensive scientific program with 40 Invited Lectures, 98 Technical Papers from 21 countries and 32 Panel Discussions with experts from all spheres of the computer field. Also at the Congress was a comprehensive exhibition of techniques and equipment as well as a videotex service to inform instantly of all the events of the congress.
The IFIP Congress '83 Program Committee, chaired by D.C. Tsichritzis, organized a technical program which allowed participants to obtain a broad view of developments in the informatics field and also to examine in detail the latest developments in specialized areas. The Program was separated into ten areas which provide a focal point for reviewing research and development activity in the informatics field. Each Invited or Submitted Lecture, and each Panel Discussion, was loosely identified