Pub Date : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189017
O. Kabranov, T. Yang, D. Makrakis
The tremendous increase in customer bandwidth demands has led to the necessity of better utilization of available bandwidth resources. We present an artificial intelligence based pricing mechanism for control of user demand in the obtainable forwarding (OF) service in DiffServ networks. By deploying a fuzzy logic controller at the DiffServ boundary node, we are able to adjust dynamically the price per unit bandwidth, depending on customer bandwidth demands and bandwidth availability. In the case of elastic traffic, a small change in price leads to a small change in customer demand. As the decision to buy bandwidth or not lies in the hands of the customer (his grade of utility), it is difficult to estimate the parameters for the customer bandwidth utility function. The suggested fuzzy controller implements rules, easily obtainable at the boundary node, using terms such as "small change", "big increase". We present an evaluation of the utilization of dynamically changing bandwidth demand.
{"title":"Fuzzy control of pricing for bandwidth demand in obtainable forwarding service for differentiated services architecture","authors":"O. Kabranov, T. Yang, D. Makrakis","doi":"10.1109/GLOCOM.2002.1189017","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189017","url":null,"abstract":"The tremendous increase in customer bandwidth demands has led to the necessity of better utilization of available bandwidth resources. We present an artificial intelligence based pricing mechanism for control of user demand in the obtainable forwarding (OF) service in DiffServ networks. By deploying a fuzzy logic controller at the DiffServ boundary node, we are able to adjust dynamically the price per unit bandwidth, depending on customer bandwidth demands and bandwidth availability. In the case of elastic traffic, a small change in price leads to a small change in customer demand. As the decision to buy bandwidth or not lies in the hands of the customer (his grade of utility), it is difficult to estimate the parameters for the customer bandwidth utility function. The suggested fuzzy controller implements rules, easily obtainable at the boundary node, using terms such as \"small change\", \"big increase\". We present an evaluation of the utilization of dynamically changing bandwidth demand.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131343523","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189018
Lixin Gao, Feng Wang
A route in the Internet may take a longer AS (autonomous systems) path than the shortest AS path due to routing policies. We systematically analyze AS paths and quantify the extent to which routing policies inflate AS paths. The results show that AS path inflation in the Internet is more prevalent than expected. We first present the extent of AS path inflation observed from the route view routing tables. From an ISP, at least 55% of AS paths are inflated by at least one AS hop and AS paths can be inflated by as long as 6 AS hops. We then employ two typical routing policies to show the extent of AS path inflation for all AS pairs; we find that at least 45% of AS paths are inflated by at least one AS hop and AS paths can be inflated by as many as 9 AS hops. Quantifying AS path inflation in the Internet has important implications on the extent of routing policies and traffic engineering performed on the Internet, and on BGP (border gateway protocol) convergence speed.
{"title":"The extent of AS path inflation by routing policies","authors":"Lixin Gao, Feng Wang","doi":"10.1109/GLOCOM.2002.1189018","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189018","url":null,"abstract":"A route in the Internet may take a longer AS (autonomous systems) path than the shortest AS path due to routing policies. We systematically analyze AS paths and quantify the extent to which routing policies inflate AS paths. The results show that AS path inflation in the Internet is more prevalent than expected. We first present the extent of AS path inflation observed from the route view routing tables. From an ISP, at least 55% of AS paths are inflated by at least one AS hop and AS paths can be inflated by as long as 6 AS hops. We then employ two typical routing policies to show the extent of AS path inflation for all AS pairs; we find that at least 45% of AS paths are inflated by at least one AS hop and AS paths can be inflated by as many as 9 AS hops. Quantifying AS path inflation in the Internet has important implications on the extent of routing policies and traffic engineering performed on the Internet, and on BGP (border gateway protocol) convergence speed.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129211659","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188492
Yang Xiao
In a 3G cellular network, the gateway location registers (GLRs), the visitor location registers (VLRs) and the home location registers (HLRs) form a three-level mobility database structure. When users leave a GLR/VLR service area, the corresponding records in the GLR/VLR are deleted. Due to mobility, a GLR/VLR database may overflow at some time periods when the number of visitors significantly increases in the GLR/VLR area. If the GLR/VLR is full, the registration procedure fails and the system cannot deliver services to incoming users under the existing cellular technology. We propose a hierarchical database overflow control mechanism in 3G cellular networks to effectively eliminate the GLR/VLR overflow problem, and incoming users can continuously use the service with insignificant extra overhead. An analytic model is proposed to investigate the performance of the hierarchical database overflow control scheme.
{"title":"Mobility database overflow control in 3G cellular networks","authors":"Yang Xiao","doi":"10.1109/GLOCOM.2002.1188492","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188492","url":null,"abstract":"In a 3G cellular network, the gateway location registers (GLRs), the visitor location registers (VLRs) and the home location registers (HLRs) form a three-level mobility database structure. When users leave a GLR/VLR service area, the corresponding records in the GLR/VLR are deleted. Due to mobility, a GLR/VLR database may overflow at some time periods when the number of visitors significantly increases in the GLR/VLR area. If the GLR/VLR is full, the registration procedure fails and the system cannot deliver services to incoming users under the existing cellular technology. We propose a hierarchical database overflow control mechanism in 3G cellular networks to effectively eliminate the GLR/VLR overflow problem, and incoming users can continuously use the service with insignificant extra overhead. An analytic model is proposed to investigate the performance of the hierarchical database overflow control scheme.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121324728","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189145
W. Hung, M. Cheung, S. Ho, Lian-Kuan Chen, Chun-Kit Chan
This paper proposes and demonstrates a nonlinear distortion reduction scheme for subcarrier multiplexed optical CATV networks based on optical sampling and optical time-division multiplexing (OTDM) techniques. Intermodulation distortion is reduced by about 10 dB for a 40-channel system. The proposed optical sampling and OTDM process is shown to induce negligible additional distortion.
{"title":"An optical sampled subcarrier multiplexing scheme for nonlinear distortion reduction in lightwave CATV networks","authors":"W. Hung, M. Cheung, S. Ho, Lian-Kuan Chen, Chun-Kit Chan","doi":"10.1109/GLOCOM.2002.1189145","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189145","url":null,"abstract":"This paper proposes and demonstrates a nonlinear distortion reduction scheme for subcarrier multiplexed optical CATV networks based on optical sampling and optical time-division multiplexing (OTDM) techniques. Intermodulation distortion is reduced by about 10 dB for a 40-channel system. The proposed optical sampling and OTDM process is shown to induce negligible additional distortion.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121398663","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189171
G. Morabito, R. Narcisi, S. Palazzo, A. Pantò
TCP-Peach has been proposed for IP network scenarios characterized by long round trip times and high bit error rates, such as satellite networks. In the TCP-Peach congestion control scheme, Slow Start and Fast Recovery are replaced with new algorithms called Sudden Start and Rapid Recovery. In this paper protocol refinements for TCP-Peach are proposed to allow it to be utilized in cooperation with FACK/SACK options. The modified protocol has been implemented in the Linux 2.2.17 kernel and its performance has been evaluated in an emulated satellite network environment. Performance results show that the modified TCP-Peach protocol outperforms other TCP implementations.
{"title":"TCP-Peach and FACK/SACK options: putting the pieces together","authors":"G. Morabito, R. Narcisi, S. Palazzo, A. Pantò","doi":"10.1109/GLOCOM.2002.1189171","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189171","url":null,"abstract":"TCP-Peach has been proposed for IP network scenarios characterized by long round trip times and high bit error rates, such as satellite networks. In the TCP-Peach congestion control scheme, Slow Start and Fast Recovery are replaced with new algorithms called Sudden Start and Rapid Recovery. In this paper protocol refinements for TCP-Peach are proposed to allow it to be utilized in cooperation with FACK/SACK options. The modified protocol has been implemented in the Linux 2.2.17 kernel and its performance has been evaluated in an emulated satellite network environment. Performance results show that the modified TCP-Peach protocol outperforms other TCP implementations.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121402589","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188033
V. Rodoplu, T. Meng
We develop a framework to evaluate the capacity of wireless ad hoc networks in which the energy supply of the nodes is the primary resource constraint. The measure of capacity in such networks is the "bits-perJoule capacity" that specifies the maximum number of bits that the network can deliver per Joule of energy in the network. First, for the one-to-one traffic model in which each node generates traffic for exactly one other randomly picked node, we demonstrate that the bits-per-Joule capacity grows with the number of nodes. Second, we demonstrate that sparse and locally-computed network topologies can approximate this capacity. Third, for ad hoc-cellular "hybrid" networks in which the node set is partitioned between an ad hoc part and a cellular part, we demonstrate under three representative traffic models, that the ad hoc topology performs far better than the cellular topology.
{"title":"Bits-per-joule capacity of energy-limited wireless ad hoc networks","authors":"V. Rodoplu, T. Meng","doi":"10.1109/GLOCOM.2002.1188033","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188033","url":null,"abstract":"We develop a framework to evaluate the capacity of wireless ad hoc networks in which the energy supply of the nodes is the primary resource constraint. The measure of capacity in such networks is the \"bits-perJoule capacity\" that specifies the maximum number of bits that the network can deliver per Joule of energy in the network. First, for the one-to-one traffic model in which each node generates traffic for exactly one other randomly picked node, we demonstrate that the bits-per-Joule capacity grows with the number of nodes. Second, we demonstrate that sparse and locally-computed network topologies can approximate this capacity. Third, for ad hoc-cellular \"hybrid\" networks in which the node set is partitioned between an ad hoc part and a cellular part, we demonstrate under three representative traffic models, that the ad hoc topology performs far better than the cellular topology.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126576280","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188355
M. Mansour, A. Tewfik
We introduce modifications to common convolutional decoders to accommodate channels with Insertions and deletions. For the Viterbi decoder, new states are added to the trellis diagram to represent the new situation and the expansion algorithm is modified accordingly. For sequential decoding, we provide modifications to the stack algorithm and a new metric is introduced. Also, we developed a systematic way for convolutional code construction using Simulated Annealing so as to maximize the distance between codewords In the presence of insertions and deletions. The proposed techniques are shown to be superior to previous approaches for this problem, and have no additional code overhead.
{"title":"Convolutional codes for channels with substitutions, insertions, and deletions","authors":"M. Mansour, A. Tewfik","doi":"10.1109/GLOCOM.2002.1188355","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188355","url":null,"abstract":"We introduce modifications to common convolutional decoders to accommodate channels with Insertions and deletions. For the Viterbi decoder, new states are added to the trellis diagram to represent the new situation and the expansion algorithm is modified accordingly. For sequential decoding, we provide modifications to the stack algorithm and a new metric is introduced. Also, we developed a systematic way for convolutional code construction using Simulated Annealing so as to maximize the distance between codewords In the presence of insertions and deletions. The proposed techniques are shown to be superior to previous approaches for this problem, and have no additional code overhead.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"8 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126065217","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188052
Yu Wang, J. Garcia-Luna-Aceves
The quest for efficient medium access control (MAC) protocols for multi-hop ad hoc networks has aroused great interest in using directional antennas. Some MAC protocols using directional antennas have been proposed in the past; they trade off spatial reuse and collision avoidance via a combination of omnidirectional and directional transmission modes. It is argued that the benefit of spatial reuse achieved by a MAC protocol that uses a directional mode in all transmissions can outweigh the benefit of a conservative collision avoidance MAC protocol that sends some omni-directional control packets to silence potential interfering nodes. We present detailed simulation experiments of the popular IEEE 802.11 MAC protocol and its variants that make use of a directional transmission mode in sufficiently random networks. It is concluded that, in contention-based MAC protocols for multi-hop networks infested with hidden terminals, the aggressive channel access scheme featured by all-directional transmissions indeed outperforms other conservative schemes in terms of enhanced throughput and reduced delay.
{"title":"Spatial reuse and collision avoidance in ad hoc networks with directional antennas","authors":"Yu Wang, J. Garcia-Luna-Aceves","doi":"10.1109/GLOCOM.2002.1188052","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188052","url":null,"abstract":"The quest for efficient medium access control (MAC) protocols for multi-hop ad hoc networks has aroused great interest in using directional antennas. Some MAC protocols using directional antennas have been proposed in the past; they trade off spatial reuse and collision avoidance via a combination of omnidirectional and directional transmission modes. It is argued that the benefit of spatial reuse achieved by a MAC protocol that uses a directional mode in all transmissions can outweigh the benefit of a conservative collision avoidance MAC protocol that sends some omni-directional control packets to silence potential interfering nodes. We present detailed simulation experiments of the popular IEEE 802.11 MAC protocol and its variants that make use of a directional transmission mode in sufficiently random networks. It is concluded that, in contention-based MAC protocols for multi-hop networks infested with hidden terminals, the aggressive channel access scheme featured by all-directional transmissions indeed outperforms other conservative schemes in terms of enhanced throughput and reduced delay.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116133877","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188470
G. Hwang, K. Sohraby
We consider the buffer requirement for a shared memory buffer arising in an ingress MPLS (multiprotocol label switching) LER (label edge router) system. The buffer is divided into virtual queues, each of which is assigned to provide a guaranteed IP service. In such a system, strong correlation between the packet interarrival times and the service times exists in each virtual queue since each packet arriving through a link with finite bandwidth is transmitted only after the system receives the entire packet. We provide a framework, including an accurate analytical model and its solution, to compute the queue length distribution for each virtual queue and the total buffer requirement for the shared memory buffer in the MPLS LER system supporting multiple guaranteed IP services simultaneously. Some numerical results on the buffer requirement and the impact of correlation on the performance are considered.
{"title":"Modelling and analysis of a buffer in an ATM-based MPLS LER system","authors":"G. Hwang, K. Sohraby","doi":"10.1109/GLOCOM.2002.1188470","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188470","url":null,"abstract":"We consider the buffer requirement for a shared memory buffer arising in an ingress MPLS (multiprotocol label switching) LER (label edge router) system. The buffer is divided into virtual queues, each of which is assigned to provide a guaranteed IP service. In such a system, strong correlation between the packet interarrival times and the service times exists in each virtual queue since each packet arriving through a link with finite bandwidth is transmitted only after the system receives the entire packet. We provide a framework, including an accurate analytical model and its solution, to compute the queue length distribution for each virtual queue and the total buffer requirement for the shared memory buffer in the MPLS LER system supporting multiple guaranteed IP services simultaneously. Some numerical results on the buffer requirement and the impact of correlation on the performance are considered.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121019317","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189112
T. Bonald, A. Proutière
We represent a data network as a set of links shared by a dynamic number of competing flows. These flows are generated within sessions and correspond to the transfer of a random volume of date on a pre-defined network route. The evolution of the stochastic process describing the number of flows on all routes, and the performance of the data transfers, depend on how link bandwidth is allocated between concurrent flows. We use some key properties of Whittle networks to characterize the class of bandwidth allocations which are insensitive in the sense that the stationary distribution of this stochastic process does not depend on any traffic characteristics (session structure, data volume distribution) except the traffic intensity on each route. This insensitivity property presents the practical interest of allowing the development of robust engineering rules independently of precise traffic statistics.
{"title":"Insensitive bandwidth sharing","authors":"T. Bonald, A. Proutière","doi":"10.1109/GLOCOM.2002.1189112","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189112","url":null,"abstract":"We represent a data network as a set of links shared by a dynamic number of competing flows. These flows are generated within sessions and correspond to the transfer of a random volume of date on a pre-defined network route. The evolution of the stochastic process describing the number of flows on all routes, and the performance of the data transfers, depend on how link bandwidth is allocated between concurrent flows. We use some key properties of Whittle networks to characterize the class of bandwidth allocations which are insensitive in the sense that the stationary distribution of this stochastic process does not depend on any traffic characteristics (session structure, data volume distribution) except the traffic intensity on each route. This insensitivity property presents the practical interest of allowing the development of robust engineering rules independently of precise traffic statistics.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125060957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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