Many storage systems rely on replication to increase the availability and durability of data on untrusted storage systems. At present, such storage systems provide no strong evidence that multiple copies of the data are actually stored. Storage servers can collude to make it look like they are storing many copies of the data, whereas in reality they only store a single copy. We address this shortcoming through multiple-replica provable data possession (MR-PDP): A provably-secure scheme that allows a client that stores t replicas of a file in a storage system to verify through a challenge-response protocol that (1) each unique replica can be produced at the time of the challenge and that (2) the storage system uses t times the storage required to store a single replica. MR-PDP extends previous work on data possession proofs for a single copy of a file in a client/server storage system (Ateniese et al., 2007). Using MR-PDP to store t replicas is computationally much more efficient than using a single-replica PDP scheme to store t separate, unrelated files (e.g., by encrypting each file separately prior to storing it). Another advantage of MR-PDP is that it can generate further replicas on demand, at little expense, when some of the existing replicas fail.
许多存储系统依靠复制来提高不可信存储系统上数据的可用性和持久性。目前，这样的存储系统并没有提供强有力的证据证明实际上存储了数据的多个副本。存储服务器可以相互勾结，使其看起来像是在存储数据的多个副本，而实际上它们只存储一个副本。我们通过多副本可证明的数据占有(MR-PDP)解决了这个缺点:一个可证明的安全方案，允许在存储系统中存储文件的t个副本的客户端通过挑战-响应协议验证:(1)每个唯一副本可以在挑战时产生，(2)存储系统使用t倍存储单个副本所需的存储空间。MR-PDP扩展了以前在客户端/服务器存储系统中文件的单个副本的数据占有证明方面的工作(Ateniese et al.， 2007)。使用MR-PDP存储t个副本比使用单副本PDP方案存储t个独立的、不相关的文件(例如，在存储每个文件之前分别加密)在计算上要高效得多。MR-PDP的另一个优点是，当一些现有的副本失败时，它可以按需生成更多的副本，而且花费很少。
{"title":"MR-PDP: Multiple-Replica Provable Data Possession","authors":"Reza Curtmola, O. Khan, R. Burns, G. Ateniese","doi":"10.1109/ICDCS.2008.68","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.68","url":null,"abstract":"Many storage systems rely on replication to increase the availability and durability of data on untrusted storage systems. At present, such storage systems provide no strong evidence that multiple copies of the data are actually stored. Storage servers can collude to make it look like they are storing many copies of the data, whereas in reality they only store a single copy. We address this shortcoming through multiple-replica provable data possession (MR-PDP): A provably-secure scheme that allows a client that stores t replicas of a file in a storage system to verify through a challenge-response protocol that (1) each unique replica can be produced at the time of the challenge and that (2) the storage system uses t times the storage required to store a single replica. MR-PDP extends previous work on data possession proofs for a single copy of a file in a client/server storage system (Ateniese et al., 2007). Using MR-PDP to store t replicas is computationally much more efficient than using a single-replica PDP scheme to store t separate, unrelated files (e.g., by encrypting each file separately prior to storing it). Another advantage of MR-PDP is that it can generate further replicas on demand, at little expense, when some of the existing replicas fail.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115823808","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}
G. Xing, Jianping Wang, Ke Shen, Qingfeng Huang, X. Jia, H. So
Wireless sensor networks (WSNs) deployed for mission-critical applications face the fundamental challenge of meeting stringent spatiotemporal performance requirements using nodes with limited sensing capacity. Although advance network planning and dense node deployment may initially achieve the required performance, they often fail to adapt to the unpredictability of physical reality. This paper explores efficient use of mobile sensors to address the limitations of static WSNs in target detection. We propose a data fusion model that enables static and mobile sensors to effectively collaborate in target detection. An optimal sensor movement scheduling algorithm is developed to minimize the total moving distance of sensors while achieving a set of spatiotemporal performance requirements including high detection probability, low system false alarm rate and bounded detection delay. The effectiveness of our approach is validated by extensive simulations based on real data traces collected by 23 sensor nodes.
{"title":"Mobility-Assisted Spatiotemporal Detection in Wireless Sensor Networks","authors":"G. Xing, Jianping Wang, Ke Shen, Qingfeng Huang, X. Jia, H. So","doi":"10.1109/ICDCS.2008.81","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.81","url":null,"abstract":"Wireless sensor networks (WSNs) deployed for mission-critical applications face the fundamental challenge of meeting stringent spatiotemporal performance requirements using nodes with limited sensing capacity. Although advance network planning and dense node deployment may initially achieve the required performance, they often fail to adapt to the unpredictability of physical reality. This paper explores efficient use of mobile sensors to address the limitations of static WSNs in target detection. We propose a data fusion model that enables static and mobile sensors to effectively collaborate in target detection. An optimal sensor movement scheduling algorithm is developed to minimize the total moving distance of sensors while achieving a set of spatiotemporal performance requirements including high detection probability, low system false alarm rate and bounded detection delay. The effectiveness of our approach is validated by extensive simulations based on real data traces collected by 23 sensor nodes.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127821281","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 most large-scale peer-to-peer (P2P) applications, it is necessary to collect vital statistics data - sometimes referred to as logs - from up to millions of peers. Traditional solutions involve sending large volumes of such data to centralized logging servers, which are not scalable. In addition, they may not be able to retrieve statistics data from departed peers in dynamic peer-to-peer systems. In this paper, we solve this dilemma through an indirect collection mechanism that distributes data using random network coding across the network, from which servers proactively pull such statistics. By buffering data in a decentralized fashion with only a small portion of peer resources, we show that our new mechanism provides a "buffering" zone and a "smoothing" factor to collect large volumes of statistics, with appropriate resilience to peer dynamics and scalability to a large peer population.
{"title":"Circumventing Server Bottlenecks: Indirect Large-Scale P2P Data Collection","authors":"Di Niu, Baochun Li","doi":"10.1109/ICDCS.2008.74","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.74","url":null,"abstract":"In most large-scale peer-to-peer (P2P) applications, it is necessary to collect vital statistics data - sometimes referred to as logs - from up to millions of peers. Traditional solutions involve sending large volumes of such data to centralized logging servers, which are not scalable. In addition, they may not be able to retrieve statistics data from departed peers in dynamic peer-to-peer systems. In this paper, we solve this dilemma through an indirect collection mechanism that distributes data using random network coding across the network, from which servers proactively pull such statistics. By buffering data in a decentralized fashion with only a small portion of peer resources, we show that our new mechanism provides a \"buffering\" zone and a \"smoothing\" factor to collect large volumes of statistics, with appropriate resilience to peer dynamics and scalability to a large peer population.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131181352","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}
Jingbin Zhang, Gang Zhou, S. Son, J. Stankovic, K. Whitehouse
In this paper, we analyze the performance of group based detection in sparse sensor networks, when the system level detection decision is made based on the detection reports generated from multiple sensing periods. Sparse deployment is essential for reducing cost of large scale sensor networks, which cover thousands of square miles. In a sparse deployment, the sensor field is only partially covered by sensorspsila sensing ranges, resulting in void sensing areas in the region, but all nodes are connected through multi-hop networking. Further, due to the unavoidable false alarms generated by a single sensor in a network, many deployed systems use group based detection to reduce system level false alarms. Despite the popularity of group based detection, few analysis works in the literature deal with group based detection. In this paper, we propose a novel approach called Markov chain based Spatial approach (MS-approach) to model group based detection in sensor networks. The M-S-approach successfully overcomes the complicated conditional detection probability of a target in each sensing period, and reduces the execution time of the analysis from many days to 1 minute. The analytical model is validated through extensive simulations. This analytical work is important because it provides an easy way to understand the performance of a system that uses group based detection without running countless simulations or deploying real systems.
{"title":"Performance Analysis of Group Based Detection for Sparse Sensor Networks","authors":"Jingbin Zhang, Gang Zhou, S. Son, J. Stankovic, K. Whitehouse","doi":"10.1109/ICDCS.2008.30","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.30","url":null,"abstract":"In this paper, we analyze the performance of group based detection in sparse sensor networks, when the system level detection decision is made based on the detection reports generated from multiple sensing periods. Sparse deployment is essential for reducing cost of large scale sensor networks, which cover thousands of square miles. In a sparse deployment, the sensor field is only partially covered by sensorspsila sensing ranges, resulting in void sensing areas in the region, but all nodes are connected through multi-hop networking. Further, due to the unavoidable false alarms generated by a single sensor in a network, many deployed systems use group based detection to reduce system level false alarms. Despite the popularity of group based detection, few analysis works in the literature deal with group based detection. In this paper, we propose a novel approach called Markov chain based Spatial approach (MS-approach) to model group based detection in sensor networks. The M-S-approach successfully overcomes the complicated conditional detection probability of a target in each sensing period, and reduces the execution time of the analysis from many days to 1 minute. The analytical model is validated through extensive simulations. This analytical work is important because it provides an easy way to understand the performance of a system that uses group based detection without running countless simulations or deploying real systems.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134207744","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 considers a multi-query optimization issue for distributed similarity query processing, which attempts to exploit the dependencies in the derivation of a query evaluation plan. To the best of our knowledge, this is the first work investigating a multi- query optimization technique for distributed similarity query processing (MDSQ). Four steps are incorporated in our MDSQ algorithm. First when a number of query requests(i.e., m query vectors and m radiuses) are simultaneously submitted by users, then a cost-based dynamic query scheduling(DQS) procedure is invoked to quickly and effectively identify the correlation among the query spheres (requests). After that, an index-based vector set reduction is performed at data node level in parallel. Finally, a refinement process of the candidate vectors is conducted to get the answer set. The proposed method includes a cost-based dynamic query scheduling, a Start-Distance(SD)-based load balancing scheme, and an index-based vector set reduction algorithm. The experimental results validate the efficiency and effectiveness of the algorithm in minimizing the response time and increasing the parallelism of I/O and CPU.
{"title":"Multi-query Optimization for Distributed Similarity Query Processing","authors":"Zhuang Yi, Qing Li, Lei Chen","doi":"10.1109/ICDCS.2008.58","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.58","url":null,"abstract":"This paper considers a multi-query optimization issue for distributed similarity query processing, which attempts to exploit the dependencies in the derivation of a query evaluation plan. To the best of our knowledge, this is the first work investigating a multi- query optimization technique for distributed similarity query processing (MDSQ). Four steps are incorporated in our MDSQ algorithm. First when a number of query requests(i.e., m query vectors and m radiuses) are simultaneously submitted by users, then a cost-based dynamic query scheduling(DQS) procedure is invoked to quickly and effectively identify the correlation among the query spheres (requests). After that, an index-based vector set reduction is performed at data node level in parallel. Finally, a refinement process of the candidate vectors is conducted to get the answer set. The proposed method includes a cost-based dynamic query scheduling, a Start-Distance(SD)-based load balancing scheme, and an index-based vector set reduction algorithm. The experimental results validate the efficiency and effectiveness of the algorithm in minimizing the response time and increasing the parallelism of I/O and CPU.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130686597","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}
Null data frames are a special but important type of frames in IEEE 802.11 based wireless local area networks (e.g., 802.11 WLANs). They are widely used for power management, channel scanning and association keeping alive. The wide applications of null data frames come from their salient features such as lightweight frame format and implementation flexibility. However, such features can be taken advantage of by malicious attackers to launch a variety of attacks. In this paper, we identify the potential security vulnerabilities in the current applications of null data frames. We then study two types of attacks taking advantage of these vulnerabilities in detail, and evaluate their effectiveness based on extensive experiments. Finally, we point out that our work has broader impact in that similar vulnerabilities exist in many other networks.
{"title":"On Security Vulnerabilities of Null Data Frames in IEEE 802.11 Based WLANs","authors":"Wenjun Gu, Zhimin Yang, Can Que, D. Xuan, W. Jia","doi":"10.1109/ICDCS.2008.17","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.17","url":null,"abstract":"Null data frames are a special but important type of frames in IEEE 802.11 based wireless local area networks (e.g., 802.11 WLANs). They are widely used for power management, channel scanning and association keeping alive. The wide applications of null data frames come from their salient features such as lightweight frame format and implementation flexibility. However, such features can be taken advantage of by malicious attackers to launch a variety of attacks. In this paper, we identify the potential security vulnerabilities in the current applications of null data frames. We then study two types of attacks taking advantage of these vulnerabilities in detail, and evaluate their effectiveness based on extensive experiments. Finally, we point out that our work has broader impact in that similar vulnerabilities exist in many other networks.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131000016","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}
It is known that CSMA/CA channel access schemes are not well suited to meet the high traffic demand of wireless mesh networks. One possible way to increase traffic carrying capacity is to use a spatial TDMA (STDMA) approach in conjunction with the physical interference model, which allows more aggressive scheduling than the protocol interference model on which CSMA/CA is based. While an efficient centralized solution for STDMA with physical interference has been recently proposed, no satisfactory distributed approaches have been introduced so far. In this paper, we first prove that no localized distributed algorithm can solve the problem of building a feasible schedule under the physical interference model. Motivated by this, we design a global primitive, called SCREAM, which is used to verify the feasibility of a schedule during an iterative distributed scheduling procedure. Based on this primitive, we present two distributed protocols for efficient, distributed scheduling under the physical interference model, and we prove an approximation bound for one of the protocols. We also present extensive packet-level simulation results, which show that our protocols achieve schedule lengths very close to those of the centralized algorithm and have running times that are practical for mesh networks.
{"title":"The SCREAM Approach for Efficient Distributed Scheduling with Physical Interference in Wireless Mesh Networks","authors":"Gurashish Singh Brar, D. Blough, P. Santi","doi":"10.1109/ICDCS.2008.104","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.104","url":null,"abstract":"It is known that CSMA/CA channel access schemes are not well suited to meet the high traffic demand of wireless mesh networks. One possible way to increase traffic carrying capacity is to use a spatial TDMA (STDMA) approach in conjunction with the physical interference model, which allows more aggressive scheduling than the protocol interference model on which CSMA/CA is based. While an efficient centralized solution for STDMA with physical interference has been recently proposed, no satisfactory distributed approaches have been introduced so far. In this paper, we first prove that no localized distributed algorithm can solve the problem of building a feasible schedule under the physical interference model. Motivated by this, we design a global primitive, called SCREAM, which is used to verify the feasibility of a schedule during an iterative distributed scheduling procedure. Based on this primitive, we present two distributed protocols for efficient, distributed scheduling under the physical interference model, and we prove an approximation bound for one of the protocols. We also present extensive packet-level simulation results, which show that our protocols achieve schedule lengths very close to those of the centralized algorithm and have running times that are practical for mesh networks.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130982930","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 the third-party model for the distribution of data, the trusted data creator or owner provides an untrusted distributor D with integrity verification (IV) items that are stored at D in addition to the n data items. When a user U has a subset of n' of those n data items and needs to verify their integrity, U is provided by D with a number of IV items that U uses to verify its data's integrity. The model forbids U from receiving any information about the n-n' data items that the user is not authorized to access, and assumes that D has no signature authority (it stores only pre-signed IVs). Most of the published work in this area uses the Merkle tree or variants thereof, and typically requires D to store a linear or close to linear (in n) number s(n) of IV items that are pre-signed by the trusted authority. Moreover, most of the existing schemes impose on D a non-constant amount of computation work t(n) (typically logarithmic in n) in order to provide U with the IV items that enable U to verify the integrity of its data; we call h(n) the number of such IV items. The h(n) values found in the literature are non-constant, i.e., they actually do depend on the number of data items. The main contribution of this paper is to achieve linear s(n), constant h(n) and constant or logarithmic t(n) when the n data items are organized in a tree hierarchy T, and the user's subset of n' items form a subtree T'. The cases of T' considered are when T' is (i) rooted at a node v and of depth k below v; and (ii) reachable in k hops from v going both up and down in T.
{"title":"Efficient Distributed Third-Party Data Authentication for Tree Hierarchies","authors":"Hao Yuan, M. Atallah","doi":"10.1109/ICDCS.2008.53","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.53","url":null,"abstract":"In the third-party model for the distribution of data, the trusted data creator or owner provides an untrusted distributor D with integrity verification (IV) items that are stored at D in addition to the n data items. When a user U has a subset of n' of those n data items and needs to verify their integrity, U is provided by D with a number of IV items that U uses to verify its data's integrity. The model forbids U from receiving any information about the n-n' data items that the user is not authorized to access, and assumes that D has no signature authority (it stores only pre-signed IVs). Most of the published work in this area uses the Merkle tree or variants thereof, and typically requires D to store a linear or close to linear (in n) number s(n) of IV items that are pre-signed by the trusted authority. Moreover, most of the existing schemes impose on D a non-constant amount of computation work t(n) (typically logarithmic in n) in order to provide U with the IV items that enable U to verify the integrity of its data; we call h(n) the number of such IV items. The h(n) values found in the literature are non-constant, i.e., they actually do depend on the number of data items. The main contribution of this paper is to achieve linear s(n), constant h(n) and constant or logarithmic t(n) when the n data items are organized in a tree hierarchy T, and the user's subset of n' items form a subtree T'. The cases of T' considered are when T' is (i) rooted at a node v and of depth k below v; and (ii) reachable in k hops from v going both up and down in T.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133997522","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}
Context-awareness allows pervasive applications to adapt to changeable computing environments. Contexts, the pieces of information that capture the characteristics of environments, are often error-prone and inconsistent due to noises. Various strategies have been proposed to enable automatic context inconsistency resolution. They are formulated on different assumptions that may not hold in practice. This causes applications to be less context-aware to different extents. In this paper, we investigate such impacts and propose our new resolution strategy. We conducted experiments to compare our work with major existing strategies. The results showed that our strategy is both effective in resolving context inconsistencies and promising in its support of applications using contexts.
{"title":"Heuristics-Based Strategies for Resolving Context Inconsistencies in Pervasive Computing Applications","authors":"Chang Xu, S. Cheung, W. Chan, Chunyang Ye","doi":"10.1109/ICDCS.2008.46","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.46","url":null,"abstract":"Context-awareness allows pervasive applications to adapt to changeable computing environments. Contexts, the pieces of information that capture the characteristics of environments, are often error-prone and inconsistent due to noises. Various strategies have been proposed to enable automatic context inconsistency resolution. They are formulated on different assumptions that may not hold in practice. This causes applications to be less context-aware to different extents. In this paper, we investigate such impacts and propose our new resolution strategy. We conducted experiments to compare our work with major existing strategies. The results showed that our strategy is both effective in resolving context inconsistencies and promising in its support of applications using contexts.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127765320","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}
Network time synchronization (NTS) is essential for any distributed systems, including disruption tolerant networks (DTNs). The feature of frequent contact disruptions and discontinuous network connections in DTNs raises a new challenge in providing the NTS service: synchronization operations may be interrupted for a long period of time when links between the time synchronization peers are opportunistic. To address this challenge, we propose double- pairwise time protocol (DTP) that can achieve better clock estimations and synchronization results in DTNs than NTP-Core, which models the major functionality of processing synchronization messages in network time protocol (NTP) that is the time-keeping standard in the Internet. The characteristics of DTP include: i) DTP achieves approximately half of the maximum time error achieved by NTP-Core; and ii) DTP only requires minor modifications to be implemented in the current architecture of NTP. Simulation results based on trace data collected from existing DTN testbeds validate such characteristics of DTP.
{"title":"DTP: Double-Pairwise Time Protocol for Disruption Tolerant Networks","authors":"Q. Ye, Liang Cheng","doi":"10.1109/ICDCS.2008.73","DOIUrl":"https://doi.org/10.1109/ICDCS.2008.73","url":null,"abstract":"Network time synchronization (NTS) is essential for any distributed systems, including disruption tolerant networks (DTNs). The feature of frequent contact disruptions and discontinuous network connections in DTNs raises a new challenge in providing the NTS service: synchronization operations may be interrupted for a long period of time when links between the time synchronization peers are opportunistic. To address this challenge, we propose double- pairwise time protocol (DTP) that can achieve better clock estimations and synchronization results in DTNs than NTP-Core, which models the major functionality of processing synchronization messages in network time protocol (NTP) that is the time-keeping standard in the Internet. The characteristics of DTP include: i) DTP achieves approximately half of the maximum time error achieved by NTP-Core; and ii) DTP only requires minor modifications to be implemented in the current architecture of NTP. Simulation results based on trace data collected from existing DTN testbeds validate such characteristics of DTP.","PeriodicalId":240205,"journal":{"name":"2008 The 28th International Conference on Distributed Computing Systems","volume":"2008 33","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120848994","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：