In view that some international bodies in the field of Telecontrol systems propose reliability requirements for line protocols which are not fulfilled by standard HDLC,here a detailed analysis of the reliability of HDLC is given and the statistical properties of sequences using the Bit Insertion Mechanism are analyzed. The final result is a proposal of a method,the Four Redundancy Bit Sequence method: (FRBS),which seems able to be added without much trouble before and after the HDLC layer to yield a protocol with the desired characteristics.
{"title":"HDLC reliability and the FRBS method to improve it","authors":"J. Selga, J. Rivera","doi":"10.1145/800081.802683","DOIUrl":"https://doi.org/10.1145/800081.802683","url":null,"abstract":"In view that some international bodies in the field of Telecontrol systems propose reliability requirements for line protocols which are not fulfilled by standard HDLC,here a detailed analysis of the reliability of HDLC is given and the statistical properties of sequences using the Bit Insertion Mechanism are analyzed. The final result is a proposal of a method,the Four Redundancy Bit Sequence method: (FRBS),which seems able to be added without much trouble before and after the HDLC layer to yield a protocol with the desired characteristics.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124481995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ideal local area network is a mechanism which provides concurrent high speed error-free data paths over a limited geographical area and between any computational entities on the network. A computational entity may be a program running on any type of computer, any intelligent device, or any terminal. This means that such an ideal network must be able to support systems of cooperating processes within disjoint and dissimilar host environments. Achieving such an ideal heterogeneous network (referred to as an “open” network with respect to the ISO Reference Model for Open Systems Interconnection) may be impossible in the limit. However, the ideal shows promise of being approachable. Recent work in local area networks, protocols, and multiprocessor operating systems looks promising for attacking the problem. This paper first discusses data paths and the dilemma of heterogeneous data communications. Existing local area networks, their functionality, shortcomings, and relationship to networking standards are described. Commercial LANs are discussed and classified. Standards, high level protocols, and operating system concepts are discussed and related to networks. Finally some possible approaches to the implementation of hetergeneous networks are discussed.
{"title":"Insights into the implementation and application of heterogeneous local area networks","authors":"W. Lidinsky","doi":"10.1145/800081.802659","DOIUrl":"https://doi.org/10.1145/800081.802659","url":null,"abstract":"The ideal local area network is a mechanism which provides concurrent high speed error-free data paths over a limited geographical area and between any computational entities on the network. A computational entity may be a program running on any type of computer, any intelligent device, or any terminal. This means that such an ideal network must be able to support systems of cooperating processes within disjoint and dissimilar host environments. Achieving such an ideal heterogeneous network (referred to as an “open” network with respect to the ISO Reference Model for Open Systems Interconnection) may be impossible in the limit. However, the ideal shows promise of being approachable. Recent work in local area networks, protocols, and multiprocessor operating systems looks promising for attacking the problem. This paper first discusses data paths and the dilemma of heterogeneous data communications. Existing local area networks, their functionality, shortcomings, and relationship to networking standards are described. Commercial LANs are discussed and classified. Standards, high level protocols, and operating system concepts are discussed and related to networks. Finally some possible approaches to the implementation of hetergeneous networks are discussed.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129455272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the advent of data communication networks, researchers have been looking at the possibility of placing copies of a database at two or more nodes of a network. Such data replication is interesting because it makes the database accessible even when some of the nodes in the system fail. Furthermore, transactions which only read data may get faster access to the data when multiple copies exist. Due to the complex and time consuming update protocols, and due to the additional required hardware, data replication has a definite cost. This cost factor is often overlooked in discussions on replicated data, so in this paper we examine some of the cost issues involved. We argue that the cost of replicating data is so high that only in very special cases will data be replicated at different nodes of a computer communication network and kept in a consistent state. We also discuss some alternate approaches to data replication (like data replication at a single node and shadow copies).
{"title":"The cost of data replication","authors":"H. Garcia-Molina, Daniel Barbará","doi":"10.1145/800081.802672","DOIUrl":"https://doi.org/10.1145/800081.802672","url":null,"abstract":"With the advent of data communication networks, researchers have been looking at the possibility of placing copies of a database at two or more nodes of a network. Such data replication is interesting because it makes the database accessible even when some of the nodes in the system fail. Furthermore, transactions which only read data may get faster access to the data when multiple copies exist. Due to the complex and time consuming update protocols, and due to the additional required hardware, data replication has a definite cost. This cost factor is often overlooked in discussions on replicated data, so in this paper we examine some of the cost issues involved. We argue that the cost of replicating data is so high that only in very special cases will data be replicated at different nodes of a computer communication network and kept in a consistent state. We also discuss some alternate approaches to data replication (like data replication at a single node and shadow copies).","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124095989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Communication failures may occur because of residual hardware or software implementation flaws, operator errors, transmission noises and transient or permanent machine failures. For packet switched network operation, some means are necessary to detect the errors and to analyze the phenomena to identify the causes of the errors, since, generally, it is almost impossible to predict errors or to implement systems without errors or failures. This paper describes general aspects of communication protocol analysis, protocol analysis technologies for CCITT X.25 and the protocol analyzer to be used in DDX packet switched network operation.
{"title":"A study of protocol analysis for packet switched network","authors":"K. Tsukamoto, T. Itoh, M. Nomura, Y. Tanaka","doi":"10.1145/800081.802664","DOIUrl":"https://doi.org/10.1145/800081.802664","url":null,"abstract":"Communication failures may occur because of residual hardware or software implementation flaws, operator errors, transmission noises and transient or permanent machine failures. For packet switched network operation, some means are necessary to detect the errors and to analyze the phenomena to identify the causes of the errors, since, generally, it is almost impossible to predict errors or to implement systems without errors or failures. This paper describes general aspects of communication protocol analysis, protocol analysis technologies for CCITT X.25 and the protocol analyzer to be used in DDX packet switched network operation.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133616553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper looks at the characteristics of the three types of information that can be expected to exist in the Automated Office of the Future:. voice, data and video. Then, it presents the three technologies (or methods), known as Local Area Networks, to support these types of information. The Local Area Networks considered here are: Central Switches, Rings and Buses. Two classes of Central Switches are considered: Circuit and Packet. Furthermore, two classes of Bus structures are also considered: Baseband and Broadband. Finally, this paper discusses the implications of each technology upon supporting each of the three types of information.
{"title":"Local area networks for the automated office - a survey","authors":"A. Braun","doi":"10.1145/800081.802673","DOIUrl":"https://doi.org/10.1145/800081.802673","url":null,"abstract":"This paper looks at the characteristics of the three types of information that can be expected to exist in the Automated Office of the Future:. voice, data and video. Then, it presents the three technologies (or methods), known as Local Area Networks, to support these types of information. The Local Area Networks considered here are: Central Switches, Rings and Buses. Two classes of Central Switches are considered: Circuit and Packet. Furthermore, two classes of Bus structures are also considered: Baseband and Broadband. Finally, this paper discusses the implications of each technology upon supporting each of the three types of information.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122053097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we present major design considerations for the development of international computer mail protocols. A simplified functional model for computer mail systems is introduced to serve as the basis of the discussion of the protocols. The general framework of the Reference Model for Open System Architecture proposed by the ISO is followed in the description of the computer mail protocol and design issues involved at each layer of the computer mail protocol are examined. The computer mail protocol is aimed at non-interactive communication between message system users.
{"title":"Design issues of protocols for computer mail","authors":"J. Garcia-Luna-Aceves, F. Kuo","doi":"10.1145/800081.802656","DOIUrl":"https://doi.org/10.1145/800081.802656","url":null,"abstract":"In this paper we present major design considerations for the development of international computer mail protocols. A simplified functional model for computer mail systems is introduced to serve as the basis of the discussion of the protocols. The general framework of the Reference Model for Open System Architecture proposed by the ISO is followed in the description of the computer mail protocol and design issues involved at each layer of the computer mail protocol are examined. The computer mail protocol is aimed at non-interactive communication between message system users.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128357361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an exercise in the verification of a connection establishment protocol. A specification language named SPEX, tailored for the needs of communications protocols, is proposed, and its relation to a semi-automated verification system, AFFIRM, is discussed. This language is then used to specify a connection protocol currently being used. Certain errors are uncovered by analysis using the verification system. However, the major portion of the protocol's operation are shown to be correct.
{"title":"Formal specification and verification of a connection establishment protocol","authors":"D. Schwabe","doi":"10.1145/800081.802654","DOIUrl":"https://doi.org/10.1145/800081.802654","url":null,"abstract":"This paper presents an exercise in the verification of a connection establishment protocol. A specification language named SPEX, tailored for the needs of communications protocols, is proposed, and its relation to a semi-automated verification system, AFFIRM, is discussed. This language is then used to specify a connection protocol currently being used. Certain errors are uncovered by analysis using the verification system. However, the major portion of the protocol's operation are shown to be correct.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114605854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A set of stations wish to transmit messages to one another over a shared link. Messages are generated either according to so called finite source or infinite source arrival statistics. The message lengths are independent identically distributed random variables. Two policies for arbitrating contention are compared: polling, and carrier sense collision detection. The maximum mean throughput rate and mean message delay is calculated as a function of model parameters.
{"title":"A theoretical performance analysis of polling and carrier sense collision detection communication systems","authors":"E. Arthurs, B. Stuck","doi":"10.1145/800081.802669","DOIUrl":"https://doi.org/10.1145/800081.802669","url":null,"abstract":"A set of stations wish to transmit messages to one another over a shared link. Messages are generated either according to so called finite source or infinite source arrival statistics. The message lengths are independent identically distributed random variables. Two policies for arbitrating contention are compared: polling, and carrier sense collision detection. The maximum mean throughput rate and mean message delay is calculated as a function of model parameters.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122226615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Double loop network architectures offer higher performance and reliability than single loop networks. In this paper, a double loop network which is optimal among all double loops is described. This network topology consists of a loop in the forward direction connecting all the neighboring nodes, and a backward loop connecting nodes that are separated by a distance @@@@@@@@N@@@@, where N is the number of nodes in the network. We show that this network is optimal in terms of hop distance between nodes, delay, throughput, and terminal reliability. The paper includes derivation of closed form expressions for the maximum and average hop distance between nodes, number of distinct routes between two farthest nodes, and throughput. The effect of node and link failures on network performance is also considered.
{"title":"Optimal loop topologies for distributed systems","authors":"C. Raghavendra, M. Gerla","doi":"10.1145/800081.802677","DOIUrl":"https://doi.org/10.1145/800081.802677","url":null,"abstract":"Double loop network architectures offer higher performance and reliability than single loop networks. In this paper, a double loop network which is optimal among all double loops is described. This network topology consists of a loop in the forward direction connecting all the neighboring nodes, and a backward loop connecting nodes that are separated by a distance @@@@@@@@N@@@@, where N is the number of nodes in the network. We show that this network is optimal in terms of hop distance between nodes, delay, throughput, and terminal reliability. The paper includes derivation of closed form expressions for the maximum and average hop distance between nodes, number of distinct routes between two farthest nodes, and throughput. The effect of node and link failures on network performance is also considered.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124837292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a framework for considering the impact of satellite communications on high level computer communication protocols. Within that framework, we present a model for analyzing these effects, and using that model, we derive some bounds on the amount of data that may be transferred over a communication channel which contains a satellite link. As our example, we use the flow control mechanism of an early version of a planned NBS transport protocol.
{"title":"Impact of satellite technology on transport flow control","authors":"R. L. Tenney, G. Falk, Douglas H. Hunt","doi":"10.1145/800081.802681","DOIUrl":"https://doi.org/10.1145/800081.802681","url":null,"abstract":"We present a framework for considering the impact of satellite communications on high level computer communication protocols. Within that framework, we present a model for analyzing these effects, and using that model, we derive some bounds on the amount of data that may be transferred over a communication channel which contains a satellite link. As our example, we use the flow control mechanism of an early version of a planned NBS transport protocol.","PeriodicalId":217472,"journal":{"name":"Proceedings of the seventh symposium on Data communications","volume":"37 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130331871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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