Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498533
Hai Liu, P. Wan, Chih-Wei Yi, X. Jia, S. Makki, Pissinou Niki
This paper addresses the maximal lifetime scheduling problem in sensor surveillance networks. Given a set of sensors and targets in a Euclidean plane, a sensor can watch only one target at a time, our task is to schedule sensors to watch targets, such that the lifetime of the surveillance system is maximized, where the lifetime is the duration that all targets are watched. We propose an optimal solution to find the target watching schedule for sensors that achieves the maximal lifetime. Our solution consists of three steps: 1) computing the maximal lifetime of the surveillance system and a workload matrix by using linear programming techniques; 2) decomposing the workload matrix into a sequence of schedule matrices that can achieve the maximal lifetime; 3) obtaining a target watching timetable for each sensor based on the schedule matrices. Simulations have been conducted to study the complexity of our proposed method and to compare with the performance of a greedy method.
{"title":"Maximal lifetime scheduling in sensor surveillance networks","authors":"Hai Liu, P. Wan, Chih-Wei Yi, X. Jia, S. Makki, Pissinou Niki","doi":"10.1109/INFCOM.2005.1498533","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498533","url":null,"abstract":"This paper addresses the maximal lifetime scheduling problem in sensor surveillance networks. Given a set of sensors and targets in a Euclidean plane, a sensor can watch only one target at a time, our task is to schedule sensors to watch targets, such that the lifetime of the surveillance system is maximized, where the lifetime is the duration that all targets are watched. We propose an optimal solution to find the target watching schedule for sensors that achieves the maximal lifetime. Our solution consists of three steps: 1) computing the maximal lifetime of the surveillance system and a workload matrix by using linear programming techniques; 2) decomposing the workload matrix into a sequence of schedule matrices that can achieve the maximal lifetime; 3) obtaining a target watching timetable for each sensor based on the schedule matrices. Simulations have been conducted to study the complexity of our proposed method and to compare with the performance of a greedy method.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"10 1","pages":"2482-2491 vol. 4"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76386780","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1497940
Jian Tang, G. Xue, C. Chandler, Weiyi Zhang
Recent research has shown that interference can make a significant impact on the performance of multihop wireless networks. Researchers have studied interference-aware topology control recently [M. Burkhart et al., 2004]. In this paper, we study routing problems in a multihop wireless network using directional antennas with dynamic traffic. We present new definitions of link and path interference that are suitable for designing better routing algorithms. We then formulate and optimally solve two power constrained minimum interference single path routing problems. Routing along paths found by our interference-aware algorithms tends to have less channel collisions and higher network throughput. Our simulation results show that, compared with the minimum power path routing algorithm, our algorithms can reduce average path interference by 40% or more at the cost of a minor power increase. We also extend our work towards survivable routing by formulating and solving the power constrained minimum interference node-disjoint path routing problem.
最近的研究表明，干扰会对多跳无线网络的性能产生重大影响。近年来，研究人员对干扰感知拓扑控制进行了研究[M]。Burkhart et al.， 2004]。本文研究了具有动态流量的定向天线多跳无线网络中的路由问题。我们提出了新的链路和路径干扰的定义，适合设计更好的路由算法。然后，我们提出并最优解决了两个功率约束最小干扰单路径路由问题。沿着我们的干扰感知算法找到的路径路由往往具有更少的信道冲突和更高的网络吞吐量。仿真结果表明，与最小功率路径路由算法相比，我们的算法可以以较小的功率增加为代价，将平均路径干扰减少40%以上。我们还通过制定和解决功率约束最小干扰节点不相交路径路由问题，将我们的工作扩展到可生存路由。
{"title":"Interference-aware routing in multihop wireless networks using directional antennas","authors":"Jian Tang, G. Xue, C. Chandler, Weiyi Zhang","doi":"10.1109/INFCOM.2005.1497940","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1497940","url":null,"abstract":"Recent research has shown that interference can make a significant impact on the performance of multihop wireless networks. Researchers have studied interference-aware topology control recently [M. Burkhart et al., 2004]. In this paper, we study routing problems in a multihop wireless network using directional antennas with dynamic traffic. We present new definitions of link and path interference that are suitable for designing better routing algorithms. We then formulate and optimally solve two power constrained minimum interference single path routing problems. Routing along paths found by our interference-aware algorithms tends to have less channel collisions and higher network throughput. Our simulation results show that, compared with the minimum power path routing algorithm, our algorithms can reduce average path interference by 40% or more at the cost of a minor power increase. We also extend our work towards survivable routing by formulating and solving the power constrained minimum interference node-disjoint path routing problem.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"62 3 1","pages":"751-760 vol. 1"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77667342","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498551
M. Chiang, Shengyu Zhang, P. Hande
A common assumption behind most of the recent research on network utility maximization is that traffic flows are elastic, which implies that their utility functions are concave and there are no hard limits on the rate allocated to each flow. These critical assumptions lead to tractability of the analytic models of utility maximization, but also limits applicability of the resulting rate allocation protocols. This paper focuses on inelastic flows and removes these restrictive and often invalid assumptions. We present several optimization frameworks, optimality conditions, and optimal algorithms. First, we consider nonconcave utility functions, which turn utility maximization into nonconvex, constrained optimization problems that are well-known to be difficult. We present conditions under which the current standard price-based distributed algorithm can still converge to the globally optimal rate allocation despite nonconcavity of utility functions. In particular, continuity of price-based rate allocation at all the optimal prices is a sufficient condition for global convergence of rate allocation by the standard algorithm, and continuity at at least one optimal price is a necessary condition. In the second part of the paper, we provide a general problem formulation of rate allocation among time-sensitive flows from real-time and streaming applications, as well as a decomposition into subproblems coordinated by pricing. After simplifying the subproblems by leveraging the optimization structures, we highlight the difficult issues of causality and time-scale, and propose an effective price-based heuristics for admission control and an optimal algorithm for a special case formulation.
{"title":"Distributed rate allocation for inelastic flows: optimization frameworks, optimality conditions, and optimal algorithms","authors":"M. Chiang, Shengyu Zhang, P. Hande","doi":"10.1109/INFCOM.2005.1498551","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498551","url":null,"abstract":"A common assumption behind most of the recent research on network utility maximization is that traffic flows are elastic, which implies that their utility functions are concave and there are no hard limits on the rate allocated to each flow. These critical assumptions lead to tractability of the analytic models of utility maximization, but also limits applicability of the resulting rate allocation protocols. This paper focuses on inelastic flows and removes these restrictive and often invalid assumptions. We present several optimization frameworks, optimality conditions, and optimal algorithms. First, we consider nonconcave utility functions, which turn utility maximization into nonconvex, constrained optimization problems that are well-known to be difficult. We present conditions under which the current standard price-based distributed algorithm can still converge to the globally optimal rate allocation despite nonconcavity of utility functions. In particular, continuity of price-based rate allocation at all the optimal prices is a sufficient condition for global convergence of rate allocation by the standard algorithm, and continuity at at least one optimal price is a necessary condition. In the second part of the paper, we provide a general problem formulation of rate allocation among time-sensitive flows from real-time and streaming applications, as well as a decomposition into subproblems coordinated by pricing. After simplifying the subproblems by leveraging the optimization structures, we highlight the difficult issues of causality and time-scale, and propose an effective price-based heuristics for admission control and an optimal algorithm for a special case formulation.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"57 1","pages":"2679-2690 vol. 4"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86286327","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498439
Arunchandar Vasan, R. Ramjee, Thomas Y. C. Woo
The total number of hotspot users around the world is expected to grow from 9.3 million at the end of 2003 to 30 million at the end of 2004 according to researcher Gartner. Given the explosive growth in hotspot wireless usage, enhancing capacity of 802.11-based hot-spot wireless networks is an important problem. In this paper, we make two important contributions. We first present the AP-CST algorithm that dynamically adjusts the carrier sense threshold (CST) in order to allow more flows to coexist in current 802.11 architectures. We then extend the current hotspot engineering paradigm by allowing every cell and AP access to all available channels. These cells are then managed by the RNC-SC algorithm running in a centralized radio network controller. This algorithm assigns mobile stations to appropriate cells/channels and adjusts transmit power values dynamically, thereby exploiting spatial heterogeneity in distribution of users at the hotspots. Through detailed and extensive simulations, we show that the performance of 802.11-based hotspots can be improved by up to 195% per-cell and 70% overall.
{"title":"ECHOS - enhanced capacity 802.11 hotspots","authors":"Arunchandar Vasan, R. Ramjee, Thomas Y. C. Woo","doi":"10.1109/INFCOM.2005.1498439","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498439","url":null,"abstract":"The total number of hotspot users around the world is expected to grow from 9.3 million at the end of 2003 to 30 million at the end of 2004 according to researcher Gartner. Given the explosive growth in hotspot wireless usage, enhancing capacity of 802.11-based hot-spot wireless networks is an important problem. In this paper, we make two important contributions. We first present the AP-CST algorithm that dynamically adjusts the carrier sense threshold (CST) in order to allow more flows to coexist in current 802.11 architectures. We then extend the current hotspot engineering paradigm by allowing every cell and AP access to all available channels. These cells are then managed by the RNC-SC algorithm running in a centralized radio network controller. This algorithm assigns mobile stations to appropriate cells/channels and adjusts transmit power values dynamically, thereby exploiting spatial heterogeneity in distribution of users at the hotspots. Through detailed and extensive simulations, we show that the performance of 802.11-based hotspots can be improved by up to 195% per-cell and 70% overall.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"23 1","pages":"1562-1572 vol. 3"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85918766","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498345
Z. Naor
The problem of searching for mobile users in cellular networks is addressed in this study. Previous studies addressing this issue have focused on the problem of searching for a single user. The underlying assumption for this approach is that some straightforward strategy of searching for multiple users can be easily derived from a single user search strategy. Unfortunately, this assumption is violated very often in practice. As it is shown in this study, the problem of maximizing the expected rate of successful searches under delay and bandwidth constraints is NP-hard. Given the conditions that each search for a single user must be over during a pre-defined time period, and that the bandwidth available for search operations is bounded from above by a pre-defined constant, when the potential locations of different users overlap, the derivation of an optimal concurrent search for many independent users from a set of optimal single user searches is NP-hard. Unfortunately, very often the potential locations of different users overlap. In reality, a cellular network has to serve many competing search requests sharing a limited bandwidth. Since the problem of maximizing the expected rate of successful searches under delay and bandwidth constraints is NP-hard, this study proposes an approximation algorithm, that is optimal for most probable cases, and nearly optimal for the worst case condition. Even under the worst case condition, the proposed method can potentially increase the expected rate of successful searches by 100%. Moreover, the proposed search strategy outperforms a greedy search strategy, that considers only the users' location probabilities and ignores their deadline constraints. Under certain conditions, the expected rate of successful searches generated by the proposed method is twice the equivalent rate generated by the greedy search strategy. In addition, the proposed search strategy outperforms a heuristic algorithm that searches around the user last known location.
{"title":"On-line search for mobile users","authors":"Z. Naor","doi":"10.1109/INFCOM.2005.1498345","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498345","url":null,"abstract":"The problem of searching for mobile users in cellular networks is addressed in this study. Previous studies addressing this issue have focused on the problem of searching for a single user. The underlying assumption for this approach is that some straightforward strategy of searching for multiple users can be easily derived from a single user search strategy. Unfortunately, this assumption is violated very often in practice. As it is shown in this study, the problem of maximizing the expected rate of successful searches under delay and bandwidth constraints is NP-hard. Given the conditions that each search for a single user must be over during a pre-defined time period, and that the bandwidth available for search operations is bounded from above by a pre-defined constant, when the potential locations of different users overlap, the derivation of an optimal concurrent search for many independent users from a set of optimal single user searches is NP-hard. Unfortunately, very often the potential locations of different users overlap. In reality, a cellular network has to serve many competing search requests sharing a limited bandwidth. Since the problem of maximizing the expected rate of successful searches under delay and bandwidth constraints is NP-hard, this study proposes an approximation algorithm, that is optimal for most probable cases, and nearly optimal for the worst case condition. Even under the worst case condition, the proposed method can potentially increase the expected rate of successful searches by 100%. Moreover, the proposed search strategy outperforms a greedy search strategy, that considers only the users' location probabilities and ignores their deadline constraints. Under certain conditions, the expected rate of successful searches generated by the proposed method is twice the equivalent rate generated by the greedy search strategy. In addition, the proposed search strategy outperforms a heuristic algorithm that searches around the user last known location.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"125 1","pages":"1186-1195 vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85401582","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498523
W. Feng, E. Kaiser, Wu-chi Feng, A. Luu
Client puzzles have been proposed in a number of protocols as a mechanism for mitigating the effects of distributed denial of service (DDoS) attacks. In order to provide protection against simultaneous attacks across a wide range of applications and protocols, however, such puzzles must be placed at a layer common to all of them; the network layer. Placing puzzles at the IP layer fundamentally changes the service paradigm of the Internet, allowing any device within the network to push load back onto those it is servicing. An advantage of network layer puzzles over previous puzzle mechanisms is that they can be applied to all traffic from malicious clients, making it possible to defend against arbitrary attacks as well as making previously voluntary mechanisms mandatory. In this paper, we outline goals which must be met for puzzles to be deployed effectively at the network layer. We then describe the design, implementation, and evaluation of a system that meets these goals by supporting efficient, fine-grained control of puzzles at the network layer. In particular, we describe modifications to existing puzzle protocols that allow them to work at the network layer, a hint-based hash-reversal puzzle that allows for the generation and verification of fine-grained puzzles at line speed in the fast path of high-speed routers, and an iptables implementation that supports transparent deployment at arbitrary locations in the network.
{"title":"Design and implementation of network puzzles","authors":"W. Feng, E. Kaiser, Wu-chi Feng, A. Luu","doi":"10.1109/INFCOM.2005.1498523","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498523","url":null,"abstract":"Client puzzles have been proposed in a number of protocols as a mechanism for mitigating the effects of distributed denial of service (DDoS) attacks. In order to provide protection against simultaneous attacks across a wide range of applications and protocols, however, such puzzles must be placed at a layer common to all of them; the network layer. Placing puzzles at the IP layer fundamentally changes the service paradigm of the Internet, allowing any device within the network to push load back onto those it is servicing. An advantage of network layer puzzles over previous puzzle mechanisms is that they can be applied to all traffic from malicious clients, making it possible to defend against arbitrary attacks as well as making previously voluntary mechanisms mandatory. In this paper, we outline goals which must be met for puzzles to be deployed effectively at the network layer. We then describe the design, implementation, and evaluation of a system that meets these goals by supporting efficient, fine-grained control of puzzles at the network layer. In particular, we describe modifications to existing puzzle protocols that allow them to work at the network layer, a hint-based hash-reversal puzzle that allows for the generation and verification of fine-grained puzzles at line speed in the fast path of high-speed routers, and an iptables implementation that supports transparent deployment at arbitrary locations in the network.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"63 1","pages":"2372-2382 vol. 4"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90265475","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498361
Mina Guirguis, Azer Bestavros, I. Matta, Y. Zhang
Current computing systems depend on adaptation mechanisms to ensure that they remain in quiescent operating regions. These regions are often defined using efficiency, fairness, and stability properties. To that end, traditional research works in scalable server architectures and protocols have focused on promoting these properties by proposing even more sophisticated adaptation mechanisms, without the proper attention to security implications. In this paper, we exemplify such security implications by exposing the vulnerabilities of admission control mechanisms that are widely deployed in Internet end systems to reduction of quality (RoQ) attacks. RoQ attacks target the transients of a system's adaptive behavior as opposed to its limited steady-state capacity. We show that a well orchestrated RoQ attack on an end-system admission control policy could introduce significant inefficiencies that could potentially deprive an Internet end-system from much of its capacity, or significantly reduce its service quality, while evading detection by consuming an unsuspicious, small fraction of that system's hijacked capacity. We develop a control theoretic model for assessing the impact of RoQ attacks on an end-system's admission controller. We quantify the damage inflicted by an attacker through deriving appropriate metrics. We validate our findings through real Internet experiments performed in our lab.
{"title":"Reduction of quality (RoQ) attacks on Internet end-systems","authors":"Mina Guirguis, Azer Bestavros, I. Matta, Y. Zhang","doi":"10.1109/INFCOM.2005.1498361","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498361","url":null,"abstract":"Current computing systems depend on adaptation mechanisms to ensure that they remain in quiescent operating regions. These regions are often defined using efficiency, fairness, and stability properties. To that end, traditional research works in scalable server architectures and protocols have focused on promoting these properties by proposing even more sophisticated adaptation mechanisms, without the proper attention to security implications. In this paper, we exemplify such security implications by exposing the vulnerabilities of admission control mechanisms that are widely deployed in Internet end systems to reduction of quality (RoQ) attacks. RoQ attacks target the transients of a system's adaptive behavior as opposed to its limited steady-state capacity. We show that a well orchestrated RoQ attack on an end-system admission control policy could introduce significant inefficiencies that could potentially deprive an Internet end-system from much of its capacity, or significantly reduce its service quality, while evading detection by consuming an unsuspicious, small fraction of that system's hijacked capacity. We develop a control theoretic model for assessing the impact of RoQ attacks on an end-system's admission controller. We quantify the damage inflicted by an attacker through deriving appropriate metrics. We validate our findings through real Internet experiments performed in our lab.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"42 1","pages":"1362-1372 vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76832149","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498357
E. Altman, Konstantin Avrachenkov, A. Kherani, B. Prabhu
We study an adaptive window protocol (AWP) with a general increase and decrease profile in the presence of window dependent random losses. We derive a steady-state Kolmogorov equation and obtain its solution in analytic form. We obtain some stochastic ordering relations for a protocol with different bounds on window. A closed form necessary and sufficient stability condition using the stochastic ordering for the window process is established. Finally, we apply the general results to particular TCP versions such as NEW Reno TCP, scalable TCP and Highspeed TCP. We observe that Highspeed TCP can be used to approximate almost any kind of window behavior by varying only one design parameter.
{"title":"Performance analysis and stochastic stability of congestion control protocols","authors":"E. Altman, Konstantin Avrachenkov, A. Kherani, B. Prabhu","doi":"10.1109/INFCOM.2005.1498357","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498357","url":null,"abstract":"We study an adaptive window protocol (AWP) with a general increase and decrease profile in the presence of window dependent random losses. We derive a steady-state Kolmogorov equation and obtain its solution in analytic form. We obtain some stochastic ordering relations for a protocol with different bounds on window. A closed form necessary and sufficient stability condition using the stochastic ordering for the window process is established. Finally, we apply the general results to particular TCP versions such as NEW Reno TCP, scalable TCP and Highspeed TCP. We observe that Highspeed TCP can be used to approximate almost any kind of window behavior by varying only one design parameter.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"17 1","pages":"1316-1327 vol. 2"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79741292","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498537
Xue Yang, N. Vaidya
The aggregate throughput of a wireless ad hoc network depends on the channel capacity, channel utilization (i.e., the fraction of channel capacity used for generating good put), and the concurrent transmissions allowed in the network. While channel utilization is determined by MAC overhead, physical carrier sense has been used as an effective way to avoid interference and exploit spatial reuse. Prior research has attempted to identify the optimal carrier sense range that can maximize the aggregate throughput. However, the impact of MAC overhead has been ignored. In this paper, we use both an analytical model and simulation results to show that MAC overhead has significant impact on the choice of optimal carrier sense range. If MAC overhead is not taken into account properly in determining the optimal carrier sense range, the aggregate throughput can suffer a significant loss.
{"title":"On physical carrier sensing in wireless ad hoc networks","authors":"Xue Yang, N. Vaidya","doi":"10.1109/INFCOM.2005.1498537","DOIUrl":"https://doi.org/10.1109/INFCOM.2005.1498537","url":null,"abstract":"The aggregate throughput of a wireless ad hoc network depends on the channel capacity, channel utilization (i.e., the fraction of channel capacity used for generating good put), and the concurrent transmissions allowed in the network. While channel utilization is determined by MAC overhead, physical carrier sense has been used as an effective way to avoid interference and exploit spatial reuse. Prior research has attempted to identify the optimal carrier sense range that can maximize the aggregate throughput. However, the impact of MAC overhead has been ignored. In this paper, we use both an analytical model and simulation results to show that MAC overhead has significant impact on the choice of optimal carrier sense range. If MAC overhead is not taken into account properly in determining the optimal carrier sense range, the aggregate throughput can suffer a significant loss.","PeriodicalId":20482,"journal":{"name":"Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.","volume":"16 1","pages":"2525-2535 vol. 4"},"PeriodicalIF":0.0,"publicationDate":"2005-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84441965","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}
Pub Date : 2005-03-13DOI: 10.1109/INFCOM.2005.1498332
Yongguang Zhang, T. Henderson
The explicit control protocol (XCP) has been proposed as a multi-level network feedback mechanism for congestion control of Internet transport protocols. Theoretical and simulation results have suggested that the protocol is stable and efficient over high bandwidth-delay product paths, while being more scalable to deploy than mechanisms that require per-flow state in routers. However, there is little operational experience with the approach. Since the deployment of XCP would require changes to both the end hosts and routers, it is important to study the implications of this new architecture before advocating such wide scale changes to Internets. This paper presents the results of an experimental study of XCP. We first implemented XCP in the Linux kernel and solved various systems issues. After validating previously reported simulation results, we studied the sensitivity of XCP's performance to various environmental factors, and discovered issues with TCP/IP configuration, capacity misestimation due to link sharing, handling of non-congestion losses, and the partial deployment of XCP queues in the network. These sensitivities can significantly reduce XCP's ability to control congestion and achieve fairness. Our contributions are twofold. First, through implementation we have revealed the challenges in platforms that lack large native data types or floating point arithmetic, and the need to keep fractions in the XCP protocol header. Second, through experiment and analysis we have identified several possibilities for XCP to enter into incorrect feedback control loops and adversely affect the performance. The challenges identified are deployment challenges intrinsic to the XCP design, and they suggest that the current proposal requires additional development and extension.
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