Vehicular networks are emerging as a new distributed system environment with myriad possible applications. Most studies on vehicular networks are carried out via simulation, given the logistical and economical problems with large-scale deployments. This paper investigates the impact of realistic radio propagation settings on the evaluation of VANET-based systems. Using a set of instrumented cars, we collected IEEE 802.11b signal propagation measurements between vehicles in a variety of urban and suburban environments. We found that signal propagation between vehicles varies in different settings, especially between line-of-sight ("down the block") and non line-of-sight ("around the corner") communication in the same setting. Using a probabilistic shadowing model, we evaluate the impact of different parameter settings on the performance of an epidemic data dissemination protocol and discuss the implications of our findings. We also suggest a variation of a basic signal propagation model that incorporates additional realism without sacrificing scalability by taking advantage of environmental information, including node locations and street information.
{"title":"Down the Block and Around the Corner The Impact of Radio Propagation on Inter-vehicle Wireless Communication","authors":"J. Otto, F. Bustamante, R. Berry","doi":"10.1109/ICDCS.2009.60","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.60","url":null,"abstract":"Vehicular networks are emerging as a new distributed system environment with myriad possible applications. Most studies on vehicular networks are carried out via simulation, given the logistical and economical problems with large-scale deployments. This paper investigates the impact of realistic radio propagation settings on the evaluation of VANET-based systems. Using a set of instrumented cars, we collected IEEE 802.11b signal propagation measurements between vehicles in a variety of urban and suburban environments. We found that signal propagation between vehicles varies in different settings, especially between line-of-sight (\"down the block\") and non line-of-sight (\"around the corner\") communication in the same setting. Using a probabilistic shadowing model, we evaluate the impact of different parameter settings on the performance of an epidemic data dissemination protocol and discuss the implications of our findings. We also suggest a variation of a basic signal propagation model that incorporates additional realism without sacrificing scalability by taking advantage of environmental information, including node locations and street information.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122966481","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}
Interactive TV/arcade games have been entertaining people for over 50 years. Nowadays a large number of legacy TV/arcade games have been ported to new platforms such as PCs by emulation. However, they generally require that the players be co-located to interact with one computer that emulates the game. This paper proposes a novel approach to turning those single-computer games into multi-computer games such that multiple players can play their favorite legacy games in real time over a computer network. The main challenge in this work is how to synchronize multiple replicas of a game without semantic knowledge about or modifications to the game. We have developed a novel synchronization algorithm and a working system to validate the ideas. In this paper we present the approach, especially the synchronization algorithm, and evaluate its effectiveness under a variety of network conditions. In future research we will extend this work on mobile devices.
{"title":"An Approach to Sharing Legacy TV/Arcade Games for Real-Time Collaboration","authors":"Sili Zhao, Du Li, Hansu Gu, Bin Shao, Ning Gu","doi":"10.1109/ICDCS.2009.26","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.26","url":null,"abstract":"Interactive TV/arcade games have been entertaining people for over 50 years. Nowadays a large number of legacy TV/arcade games have been ported to new platforms such as PCs by emulation. However, they generally require that the players be co-located to interact with one computer that emulates the game. This paper proposes a novel approach to turning those single-computer games into multi-computer games such that multiple players can play their favorite legacy games in real time over a computer network. The main challenge in this work is how to synchronize multiple replicas of a game without semantic knowledge about or modifications to the game. We have developed a novel synchronization algorithm and a working system to validate the ideas. In this paper we present the approach, especially the synchronization algorithm, and evaluate its effectiveness under a variety of network conditions. In future research we will extend this work on mobile devices.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128513155","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}
Recent years have witnessed the pilot deployments of audio or low-rate video wireless sensor networks for a class of mission-critical applications including search and rescue, security surveillance, and disaster management. In this paper, we report the design and implementation of Quality-aware Voice Streaming (QVS) for wireless sensor networks. QVS is built upon SenEar, a new sensor hardware platform we developed for high-bandwidth wireless audio communication. QVS comprises several novel components, which include an empirical model for online voice quality evaluation and control, dynamic voice compression/duplication adaptation for lossy wireless links, and distributed stream admission control that exploits network capacity for rate allocation. We have extensively tested QVS on a 20-node network deployment. Our experimental results show that QVS delivers satisfactory voice quality under a range of realistic settings while achieving high network capacity utilization.
{"title":"QVS: Quality-Aware Voice Streaming for Wireless Sensor Networks","authors":"Liqun Li, G. Xing, Limin Sun, Yan Liu","doi":"10.1109/ICDCS.2009.40","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.40","url":null,"abstract":"Recent years have witnessed the pilot deployments of audio or low-rate video wireless sensor networks for a class of mission-critical applications including search and rescue, security surveillance, and disaster management. In this paper, we report the design and implementation of Quality-aware Voice Streaming (QVS) for wireless sensor networks. QVS is built upon SenEar, a new sensor hardware platform we developed for high-bandwidth wireless audio communication. QVS comprises several novel components, which include an empirical model for online voice quality evaluation and control, dynamic voice compression/duplication adaptation for lossy wireless links, and distributed stream admission control that exploits network capacity for rate allocation. We have extensively tested QVS on a 20-node network deployment. Our experimental results show that QVS delivers satisfactory voice quality under a range of realistic settings while achieving high network capacity utilization.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124550159","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}
Block-level continuous data protection (CDP) logs every disk block update so that disk updates within a time window are undoable. Standard file servers and DBMS servers can enjoy the data protection service offered by block-level CDP without any modification. Unfortunately, no existing block-level CDP systems can provide users a file versioning view on top of the block versions they maintain. As a result, the data they maintain cannot be used as an extension to the on-line system with which users routinely interact. This paper describes a name-based user-level file versioning system called UVFS that is designed to reconstruct file versions from disk block versions maintained by a block-level CDP. UVFS reconstructs file versions by following the last modified time of files and directories, a common file metadata supported by almost all modern file systems, and therefore does not require any modification to the host file system that a block-level CDP system protects. In addition, UVFS incorporates a file system-specific incremental consistency check mechanism to quickly convert an arbitrary point-in-time block-level snapshot to a file system-consistent one. Performance measurements taken from a fully operational UVFS prototype show that the average end-to-end elapsed time required to discover a file version is under 50 msec from the perspective of an NFS client serviced by an NFS server backed by a block-level CDP system.
{"title":"File Versioning for Block-Level Continuous Data Protection","authors":"Maohua Lu, T. Chiueh","doi":"10.1109/ICDCS.2009.48","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.48","url":null,"abstract":"Block-level continuous data protection (CDP) logs every disk block update so that disk updates within a time window are undoable. Standard file servers and DBMS servers can enjoy the data protection service offered by block-level CDP without any modification. Unfortunately, no existing block-level CDP systems can provide users a file versioning view on top of the block versions they maintain. As a result, the data they maintain cannot be used as an extension to the on-line system with which users routinely interact. This paper describes a name-based user-level file versioning system called UVFS that is designed to reconstruct file versions from disk block versions maintained by a block-level CDP. UVFS reconstructs file versions by following the last modified time of files and directories, a common file metadata supported by almost all modern file systems, and therefore does not require any modification to the host file system that a block-level CDP system protects. In addition, UVFS incorporates a file system-specific incremental consistency check mechanism to quickly convert an arbitrary point-in-time block-level snapshot to a file system-consistent one. Performance measurements taken from a fully operational UVFS prototype show that the average end-to-end elapsed time required to discover a file version is under 50 msec from the perspective of an NFS client serviced by an NFS server backed by a block-level CDP system.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124659275","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 distributed storage systems, erasure codes represent an attractive solution to add redundancy to stored data while limiting the storage overhead. They are able to provide the same reliability as replication requiring much less storage space. Erasure coding breaks the data into pieces that are encoded and then stored on different nodes. However, when storage nodes permanently abandon the system, new redundant pieces must be created. For erasure codes, generating a new piece requires the transmission of k pieces over the network, resulting in a k times higher reconstruction traffic as compared to replication. Dimakis proposed a new class of codes, called Regenerating Codes, which are able to provide both the storage efficiency of erasure codes and the communication efficiency of replication. However, Dimakis gave only a theoretical description of the codes without discussing implementation issues or computational costs. We have done a real implementation of Random Linear Regenerating Codes that allows us to measure their computational cost, which can be significant if the parameters are not chosen properly. However, we also find that there exist parameter values that result in a significant reduction of the communication overhead at the expense of a small increase in storage cost and computation, which makes these codes very attractive for distributed storage systems.
{"title":"A Practical Study of Regenerating Codes for Peer-to-Peer Backup Systems","authors":"Alessandro Duminuco, E. Biersack","doi":"10.1109/ICDCS.2009.14","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.14","url":null,"abstract":"In distributed storage systems, erasure codes represent an attractive solution to add redundancy to stored data while limiting the storage overhead. They are able to provide the same reliability as replication requiring much less storage space. Erasure coding breaks the data into pieces that are encoded and then stored on different nodes. However, when storage nodes permanently abandon the system, new redundant pieces must be created. For erasure codes, generating a new piece requires the transmission of k pieces over the network, resulting in a k times higher reconstruction traffic as compared to replication. Dimakis proposed a new class of codes, called Regenerating Codes, which are able to provide both the storage efficiency of erasure codes and the communication efficiency of replication. However, Dimakis gave only a theoretical description of the codes without discussing implementation issues or computational costs. We have done a real implementation of Random Linear Regenerating Codes that allows us to measure their computational cost, which can be significant if the parameters are not chosen properly. However, we also find that there exist parameter values that result in a significant reduction of the communication overhead at the expense of a small increase in storage cost and computation, which makes these codes very attractive for distributed storage systems.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126372452","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 recent years, there are substantial demands to reduce packet loss in the Internet. Among the schemes proposed, finding backup paths in advance is considered to be an effective method to reduce the reaction time. Very commonly, a backup path is chosen to be a most disjoint path from the primary path, or in the network level, backup paths are computed for all links (e.g., IPRFF). The validity of this straightforward choice is based on 1) all the links may fail with equal probability; and 2) facing the high protection requirement today, having links not protected or sharing links between the primary and backup paths just simply look weird. Nevertheless, indications from many research studies have confirmed that the vulnerability of the links in the Internet is far from equality. In addition, we have seen that full protection schemes may introduce high costs. In this paper, we argue that such approaches may not be cost effective. We first analyze the failure characteristics based on real world traces from CERNET2, the China education and Research NETwork 2. We observe that the failure probabilities of the links is heavy-tail, i.e., a small set of links caused most of the failures. We thus propose a selective protection scheme. We carefully analyze the implementation details and the overhead for general backup path schemes of the Internet today. We formulate an optimization problem where the routing performance (in terms of network level availability) should be guaranteed and the backup cost should be minimized. This cost is special as it involves computation overhead. Consequently, we propose a novel Critical-Protection Algorithm which is fast itself. We evaluate our scheme systematically, using real world topologies and randomly generated topologies. We show significant gain even when the network availability requirement is 99.99% as compared to that of the full protection scheme.
{"title":"Selective Protection: A Cost-Efficient Backup Scheme for Link State Routing","authors":"M. Hou, Dan Wang, Mingwei Xu, Jiahai Yang","doi":"10.1109/ICDCS.2009.7","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.7","url":null,"abstract":"In recent years, there are substantial demands to reduce packet loss in the Internet. Among the schemes proposed, finding backup paths in advance is considered to be an effective method to reduce the reaction time. Very commonly, a backup path is chosen to be a most disjoint path from the primary path, or in the network level, backup paths are computed for all links (e.g., IPRFF). The validity of this straightforward choice is based on 1) all the links may fail with equal probability; and 2) facing the high protection requirement today, having links not protected or sharing links between the primary and backup paths just simply look weird. Nevertheless, indications from many research studies have confirmed that the vulnerability of the links in the Internet is far from equality. In addition, we have seen that full protection schemes may introduce high costs. In this paper, we argue that such approaches may not be cost effective. We first analyze the failure characteristics based on real world traces from CERNET2, the China education and Research NETwork 2. We observe that the failure probabilities of the links is heavy-tail, i.e., a small set of links caused most of the failures. We thus propose a selective protection scheme. We carefully analyze the implementation details and the overhead for general backup path schemes of the Internet today. We formulate an optimization problem where the routing performance (in terms of network level availability) should be guaranteed and the backup cost should be minimized. This cost is special as it involves computation overhead. Consequently, we propose a novel Critical-Protection Algorithm which is fast itself. We evaluate our scheme systematically, using real world topologies and randomly generated topologies. We show significant gain even when the network availability requirement is 99.99% as compared to that of the full protection scheme.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133078973","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 dramatic scale-up of distributed computing platforms is underway. Internet routers can contain hundreds or thousands of line cards. Cloud computing platforms may contain tens or even hundreds of thousands of machines. What is gluing all of this together? Multicast to support data replication, event streams, and coordination. Yet yesterday?s multicast protocols are poorly matched to this new generation of uses; so much so that many cloud platforms refuse to deploy multicast as such, and have instead resorted to clumsy alternatives, mapping multicast to TCP or even web services method invocations. This talk will explore inadequacies of existing protocols, early progress towards better ones, and the longer term research agenda.
{"title":"Rethinking Multicast for Massive-Scale Platforms","authors":"K. Birman","doi":"10.1109/ICDCS.2009.84","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.84","url":null,"abstract":"A dramatic scale-up of distributed computing platforms is underway. Internet routers can contain hundreds or thousands of line cards. Cloud computing platforms may contain tens or even hundreds of thousands of machines. What is gluing all of this together? Multicast to support data replication, event streams, and coordination. Yet yesterday?s multicast protocols are poorly matched to this new generation of uses; so much so that many cloud platforms refuse to deploy multicast as such, and have instead resorted to clumsy alternatives, mapping multicast to TCP or even web services method invocations. This talk will explore inadequacies of existing protocols, early progress towards better ones, and the longer term research agenda.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115037782","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 derive a theoretical model to calculate the available bandwidth of a path and study its upper and lower bounds with background traffic. We show that the clique constraint widely used to construct upper bounds does not hold any more when links are allowed to use different rates at different time. In our proposed model, traditional clique is coupled with rate vector to more properly characterize the conflicting relationships among links in wireless sensor networks where time-varying link adaption is used. Based on the model, we also investigate the problem of joint optimization of QoS routing and propose several routing metrics. The newly proposed conservative clique constraint performs the best among the studied metrics in estimating available bandwidth of flows with background traffic.
{"title":"Available Bandwidth in Multirate and Multihop Wireless Sensor Networks","authors":"Feng Chen, H. Zhai, Yuguang Fang","doi":"10.1109/ICDCS.2009.66","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.66","url":null,"abstract":"In this paper, we derive a theoretical model to calculate the available bandwidth of a path and study its upper and lower bounds with background traffic. We show that the clique constraint widely used to construct upper bounds does not hold any more when links are allowed to use different rates at different time. In our proposed model, traditional clique is coupled with rate vector to more properly characterize the conflicting relationships among links in wireless sensor networks where time-varying link adaption is used. Based on the model, we also investigate the problem of joint optimization of QoS routing and propose several routing metrics. The newly proposed conservative clique constraint performs the best among the studied metrics in estimating available bandwidth of flows with background traffic.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128577898","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}
Maintaining cache consistency in mobile environment is an important issue which is extensively studied in the last decade. In mobile ad hoc networks (MANETs), a large number of nonstationary mobile terminals connect with each other through multi-hop unreliable communication channels, coupling with the fact that disconnections from the network are very frequent. Most existing cache consistency strategies assume reliable communication between mobile terminals, which cannot handle frequently offline devices adequately. In this paper, we introduce the probabilistic cache consistency model for applications not requiring strong consistency. Based on this model, a probability consistency strategy (ProP) for frequently offline devices in MANETs is studied. ProP is a randomized pull-based Strategy. It is demostrated to guarantee cache consistency with a high probability. A theoretical model is developed to investigate the performance of the proposed cache consistency strategies, and design guidelines are provided for ProP to choose proper system parameters to achieve probabilistic cache consistency.
{"title":"Maintaining Probabilistic Consistency for Frequently Offline Devices in Mobile Ad Hoc Networks","authors":"Wenzhong Li, E. Chan, Daoxu Chen, Sanglu Lu","doi":"10.1109/ICDCS.2009.23","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.23","url":null,"abstract":"Maintaining cache consistency in mobile environment is an important issue which is extensively studied in the last decade. In mobile ad hoc networks (MANETs), a large number of nonstationary mobile terminals connect with each other through multi-hop unreliable communication channels, coupling with the fact that disconnections from the network are very frequent. Most existing cache consistency strategies assume reliable communication between mobile terminals, which cannot handle frequently offline devices adequately. In this paper, we introduce the probabilistic cache consistency model for applications not requiring strong consistency. Based on this model, a probability consistency strategy (ProP) for frequently offline devices in MANETs is studied. ProP is a randomized pull-based Strategy. It is demostrated to guarantee cache consistency with a high probability. A theoretical model is developed to investigate the performance of the proposed cache consistency strategies, and design guidelines are provided for ProP to choose proper system parameters to achieve probabilistic cache consistency.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127548763","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}
Nuno M. Preguiça, J. Marquès, M. Shapiro, Mihai Letia
A Commutative Replicated Data Type (CRDT) is one where all concurrent operations commute. The replicas of a CRDT converge automatically, without complex concurrency control. This paper describes Treedoc, a novel CRDT design for cooperative text editing. An essential property is that the identifiers of Treedoc atoms are selected from a dense space. We discuss practical alternatives for implementing the identifier space based on an extended binary tree. We also discuss storage alternatives for data and meta-data, and mechanisms for compacting the tree. In the best case, Treedoc incurs no overhead with respect to a linear text buffer. We validate the results with traces from existing edit histories.
{"title":"A Commutative Replicated Data Type for Cooperative Editing","authors":"Nuno M. Preguiça, J. Marquès, M. Shapiro, Mihai Letia","doi":"10.1109/ICDCS.2009.20","DOIUrl":"https://doi.org/10.1109/ICDCS.2009.20","url":null,"abstract":"A Commutative Replicated Data Type (CRDT) is one where all concurrent operations commute. The replicas of a CRDT converge automatically, without complex concurrency control. This paper describes Treedoc, a novel CRDT design for cooperative text editing. An essential property is that the identifiers of Treedoc atoms are selected from a dense space. We discuss practical alternatives for implementing the identifier space based on an extended binary tree. We also discuss storage alternatives for data and meta-data, and mechanisms for compacting the tree. In the best case, Treedoc incurs no overhead with respect to a linear text buffer. We validate the results with traces from existing edit histories.","PeriodicalId":387968,"journal":{"name":"2009 29th IEEE International Conference on Distributed Computing Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130962535","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：