共查询到20条相似文献,搜索用时 31 毫秒
1.
Yan Zhang Lemin Li Sheng Wang 《AEUE-International Journal of Electronics and Communications》2009,63(4):294-303
In TCP over optical burst switching (OBS) networks, consecutive multiple packet losses are common since an optical burst usually contains a number of consecutive packets from the same TCP sender. It has been proved that over OBS networks Reno and New-Reno achieve lower throughput performances than that of SACK, which can address the inefficiency of Reno and New-Reno in dealing with consecutive multiple packet losses. However, SACK adopts complex mechanisms not only at the sender's but also at the receiver's protocol stack, and thus has a higher difficulty in deployment.In this paper we propose B-Reno, a new TCP implementation designed for TCP over OBS networks. Using some simple modifications to New-Reno only at the sender's protocol stack, B-Reno can overcome the inefficiencies of Reno and New-Reno in dealing with consecutive multiple packet losses and thus improve their throughputs over OBS networks. Moreover, B-Reno can also achieve performance similar with that of SACK over OBS networks while avoiding SACK's difficulty in deployment due to complex mechanisms at both the sender's and the receiver's protocol stack. 相似文献
2.
Burst assembly mechanism is one of the fundamental factors that determine the performance of an optical burst switching (OBS)
network. In this paper, we investigate the influence of the number of burstifiers on TCP performance for an OBS network. The
goodput of TCP flows between an ingress node and an egress node traveling through an optical network is studied as the number
of assembly buffers per destination varies. First, the burst-length independent losses resulting from the contention in the
core OBS network using a non-void-filling burst scheduling algorithm, e.g., Horizon, are studied. Then, burst-length dependent
losses arising as a result of void-filling scheduling algorithms, e.g., LAUC-VF, are studied for two different TCP flow models:
FTP-type long-lived flows and variable size short-lived flows. Simulation results show that for both types of scheduling algorithms,
both types of TCP flow models, and different TCP versions (Reno, Newreno and Sack), TCP goodput increases as the number of
burst assemblers per egress node is increased for an OBS network employing timer-based assembly algorithm. The improvement
from one burstifier to moderate number of burst assemblers is significant (15–50% depending on the burst loss probability,
per-hop processing delay, and the TCP version), but the goodput difference between moderate number of buffers and per-flow
aggregation is relatively small, implying that an OBS edge switch should use moderate number of assembly buffers per destination
for enhanced TCP performance without substantially increasing the hardware complexity.
相似文献
Ezhan Karasan (Corresponding author)Email: |
3.
Takuji Tachibana 《Photonic Network Communications》2009,17(3):245-254
Recently, optical switching and packet processing technologies have been developed and high-performance optical burst switching
(OBS) networks are constructed by using these technologies. In high-performance OBS networks, several types of applications
such as Grid computing and HDTV can be provided for users according to immediate reservation protocol. Because some applications
require that data is transmitted reliably over high-performance OBS networks, it is indispensable to provide reliable data
transfer service for high-priority users. Therefore, in this paper, we propose a reliable burst transmission method which
can be available for the immediate reservation protocol. In the proposed method, both burst-cluster transmission and probabilistic
pre-emption are used at edge and core nodes. By using these methods together, the reliable data transfer and the service differentiation
can be provided. We evaluate by simulation the performance of the proposed method in the 14-node NSFNET. Numerical examples
show that the proposed method can transmit higher-priority bursts more reliably than the conventional method while not increasing
the overall burst loss probability so much. In addition, we investigate effective parameter settings from some simulation
results.
相似文献
Takuji TachibanaEmail: |
4.
FMIPv6 can reduce packet loss using a tunnel-based handover mechanism which relies on L2 triggers, such as transmitting a
packet from a previous access router (PAR) to a new access router (NAR). However, this mechanism may result in decreasing
the performance of TCP due to out-of-sequence packets arriving between the tunneled packets from the Home Agent and PAR, and
the directly transmitted packets from the correspondent node (CN). In this paper, we propose a new scheme called EF-MIPv6
that uses a modified snoop protocol to prevent the packet reordering problem. This new scheme can prevent sequence reordering
of data packets and improve the performance of TCP using enhanced fast binding update (EF-BU). This approach requires modification
of the TCP header to execute the last packet expression from the PAR, include a new polling data packet, and use the modified
access point system. Simulation results demonstrate that managing the packet sequence in our proposed scheme greatly increases
the overall TCP performance in a Mobile IPv6 and FMIPv6 networks.
相似文献
Haniph LatchmanEmail: |
5.
In the Stream Control Transmission Protocol (SCTP), when a portion of a packet is corrupted, the entire packet will be discarded
at the receiver side. This may result in degradation of the throughput of SCTP over wireless networks with a high bit error
rate. This paper proposes a new error control scheme of SCTP using a partial Cyclic Redundancy Check (CRC) checksum to enhance
the throughput performance, in which a new ‘checksum chunk’ is introduced to effectively identify any corruptions of data
chunks contained in the SCTP packet. In the proposed scheme, an SCTP data packet can carry one or more data chunks depending
on the channel condition, and the newly defined ‘checksum’ chunk will contain the partial CRC checksums of the individual
data chunks and/or the base header of the packet. By referring to these partial checksums, the receiver can discard only the
corrupted data chunks, whereas the other available data chunks can be recovered. Simulation results show that the proposed
scheme significantly provides better performance than the standard SCTP in the wireless networks.
相似文献
Seok Joo Koh (Corresponding author)Email: |
6.
Akbar Ghaffar Pour Rahbar 《Photonic Network Communications》2009,17(3):226-237
Optical Packet Switching (OPS) can provide the ever-increasing bandwidth required for Internet traffic and new applications
for future networks. However, optical packet loss is the major problem for an OPS network. Moreover, by increasing the number
of hops between a pair of ingress–egress switches in an OPS network, optical Packet Loss Rate (PLR) between this pair is increased.
Therefore, due to a higher PLR for long-hop TCP connections, the throughput of these connections may be much lower than the
short-hop TCP connections. To overcome this problem, it is proposed in this paper to use the retransmission idea in the optical
domain not only to increase TCP throughput but also to improve the throughput of multi-hop TCP connections, and also to have
a loss-free OPS network. Under retransmission in the optical domain, a copy of the transmitted traffic is kept in the electronic
buffers of ingress switches and retransmitted in the optical domain whenever required. Note that the TCP layer has its own
retransmission at the client packet level as well. By retransmission of lost packets in the optical domain, TCP would be unaware
of the lost client packets, and therefore, TCP would not reduce its sending rate. In this paper, TCP throughput is studied
in a bufferless slotted OPS network and the effectiveness of the proposed mechanism is evaluated.
相似文献
Akbar Ghaffar Pour RahbarEmail: Email: |
7.
Onur Alparslan Shin’ichi Arakawa Masayuki Murata 《Photonic Network Communications》2009,18(2):237-243
According to a famous rule-of-thumb, buffer size of each output link of a router should be set to bandwidth-delay product
of the network, in order to achieve high utilization with TCP flows. However, ultra high speed of optical networks makes it
very hard to satisfy this rule-of-thumb, especially with limited choices of buffering in the optical domain, because optical
RAM is under research and it is not expected to have a large capacity, soon. In this article, we evaluate the performance
of our explicit congestion control protocol-based architecture designed for very small Optical RAM-buffered optical packet
switched wavelength division multiplexing networks with pacing at edge nodes in order to decrease the required buffer size
at core nodes. By using a mesh topology and applying TCP traffic, we evaluate the optical buffer size requirements of this
architecture and compare with a common proposal in the literature.
相似文献
Onur AlparslanEmail: |
8.
Advances in enabling technologies and the explosive growth of Internet traffic has led to the widespread proliferation of
network systems in recent years. With their relatively low cost, high throughputs, high-bandwidth utilization, and low-transmission
latency, Optical Burst Switching (OBS) networks represent an ideal solution for next-generation Internet applications. However,
in OBS networks, Burst Header Packet (BHP) contentions occur when two or more BHPs are switched simultaneously to the same
output port of a given core node. These contention events result in significant losses of the corresponding data burst. Accordingly,
this study presents a Store-and-forward COntention-REsolution mechanism, designated as SCORE, which utilizes fiber delay line
buffers to resolve the BHP collision problem, thereby minimizing the burst loss rate. The results of a series of simulations
performed using an OIRC OBS-ns simulator confirm the effectiveness and efficiency of the proposed scheme.
相似文献
Tse-Sheng LinEmail: |
9.
A service differentiation scheme in optical burst switching (OBS) networks, which is based on dynamic fiber delay line (FDL)
assignment, is shown. The effectiveness of the scheme is validated by numerical analysis and extensive simulations. Especially,
the feasibility conditions for the service differentiation scheme, which are considered as the minimum number of FDLs for
each sub-FDL group, are displayed. The feasibility conditions are derived numerically, and are verified through extensive
simulations. The results of extensive simulations show that the proposed scheme and the feasibility conditions are valid for
service differentiation in OBS networks.
相似文献
Minho KangEmail: |
10.
Sheng-Chang Chen Chyi-Ren Dow Ren-Di Wang Yi-Hsung Li Shiow-Fen Hwang 《Wireless Personal Communications》2009,48(3):441-462
Multicasting is an essential service for mobile ad-hoc networks. A major challenge for multicasting in mobile ad-hoc networks
(MANETs) is the unstable forwarding path. This work presents a reliable multicasting protocol for mobile ad-hoc networks.
A virtual backbone is used as a shared structure for multiple sessions. A lost packet recovery scheme is developed for reliable
packet transmission, called the Recovery Point (RP) scheme. The RP scheme maintains the data packets received from the source
for recovering lost packets for its downstream RPs. In addition, we combine the Forward Error Correction (FEC) technology
with our RP scheme to enhance the reliability of our RP scheme. A mergence scheme for RP is also proposed to avoid excessive
control overhead. Our RP and FEC based scheme can be used to improve the reliability and efficiency of the traditional non-acknowledged
multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme. The results demonstrate that
our scheme outperforms other schemes in terms of packet delivery ratio and multicast efficiency. Furthermore, the simulation
results also demonstrate that our approach is stable in networks with high mobility.
相似文献
Shiow-Fen HwangEmail: |
11.
Robust Packet Video Transport Over Wireless Fading Channels Using a Joint Source-channel Coding Approach 总被引:2,自引:2,他引:0
In this paper, we address the problem of robust video transmission over wireless networks. Specifically, we consider packet
video transmission over wireless IP networks based on the RTP/UDP/IP protocol stack. Digital video delivered over wireless
networks is expected to suffer quality degradation from both packet loss and bit errors in the payload. In this paper, both
packet loss and bit errors in the payload are considered and the performance of a joint source-channel coding (JSCC) approach
employing forward error-correction (FEC) coding schemes for H.263 + video transmission is studied. Results indicate that
with an appropriate JSCC approach, FEC-based error-control techniques can significantly improve the packetization efficiency
for a given end-to-end quality requirement and lead to more acceptable video delivery quality over time-varying wireless networks.
Another important observation is that with a JSCC approach the fading effects of wireless links upon end-to-end video quality
are substantially decreased compared to a system without using channel coding, resulting in attractive robust performance
characteristics.
相似文献
Yong PeiEmail: |
12.
Performance comparisons of restoration techniques in optical burst switching networks 总被引:1,自引:0,他引:1
This paper describes restoration techniques for OBS networks. First, we introduce the design issues to be essentially considered,
when restoration techniques will be built into OBS networks. Second, considering the design issues, we propose a novel restoration
model named “Recover-Then-Reserve,” which can enhance the restoration performance. Third, we develop a simulator using the
NS-2 platform to verify the performance of the restoration techniques (path, link, and sub-path) designed by each restoration
model (GMPLS-based OBS restoration and our proposal). Performance is evaluated on the following metrics: restoration success
rate, restoration time, connection availability, and burst loss probability. The effects of the failure frequency and the
number of the restoration attempts on the restoration performance are also investigated. Our experiments show that the proposal
can reduce the restoration time by about 25 ms compared to the GMPLS-based OBS restoration model. Also, path restoration technique
has better performance than link and sub-path restoration techniques because it has the highest restoration success rate,
allowing similar restoration time. Our experiments also show that the more the restoration attempts made and the less the
failure frequency becomes, the better the restoration performance obtained.
相似文献
Hong Shik Park (Corresponding author)Email: |
13.
A novel optical buffering architecture for Optical Packet Switching (OPS) networks is proposed in this article. The architecture
which adopts a fiber-sharing mechanism aims at solving the problem of using a large number of fiber delay lines that are used
to solve resource contention in the core node in OPS networks. The new architecture employs fewer fiber delay lines compared
to other simple architectures, but can achieve the same performance. Simulation results and analysis show that the new architecture
can decrease packet loss probability effectively and achieve reasonable performance in average packet delay.
相似文献
Fang GuoEmail: |
14.
Optical burst switching (OBS) presents itself as a promising technology for bridging the gap between optical wavelength switching
and optical packet switching. Increasingly, researchers attempt to incorporate more realistic constraints into the design
of OBS networks. Optical signal transmission quality is subject to various types of physical impairment introduced by optical
fibers, switching equipment, or other network components. The signal degradation due to physical impairments may be significant
enough such that the bit-error rate of received signals is unacceptably high at the destination, rendering the signal not
usable. In this paper, based on earlier work, we study the burst scheduling problem in OBS networks, taking into account physical
impairment effects. We propose three effective burst scheduling algorithms: (1) a JET based Physical Impairment Constrained
Algorithm (JETPIC), (2) an Integrated Physical Impairment Constrained Algorithm (IPIC), and (3) an Enhanced Integrated Physical
Impairment Constrained Algorithm (EIPIC). At an OBS node, the proposed algorithms schedule bursts for transmission by searching
for available resources as well as verifying signal quality. Our simulation results show that the proposed algorithms are
effective in terms of reducing the burst blocking probability. In general, algorithm JETPIC outperforms algorithms IPIC and
EIPIC in burst blocking probability and average end-to-end delay performance.
相似文献
Bin WangEmail: |
15.
Sakib A. Mondal 《Wireless Networks》2009,15(3):331-340
Mobile IP is a network layer protocol for handling mobility of hosts in the Internet. However, mobile IP handoff causes degradation
of TCP performance. Hence, there is a need for improving performance of TCP over mobile IP in wireless mobile networks. We
propose an approach which handles losses due to both wireless link errors and host mobility. To handle losses due to host
mobility, a method for seamless handoff is proposed. Empirical results show that the scheme provides substantial improvement
of performance.
Sakib A. Mondal is a Senior Researcher at General Motors Research. He has received his doctorate in Management Information Systems from Indian Institute of Management Calcutta, and has worked for almost twelve years in various areas of Information Technology. His research interests include mobile and distributed computing, performance engineering, optimization and heuristic search. 相似文献
Sakib A. MondalEmail: |
Sakib A. Mondal is a Senior Researcher at General Motors Research. He has received his doctorate in Management Information Systems from Indian Institute of Management Calcutta, and has worked for almost twelve years in various areas of Information Technology. His research interests include mobile and distributed computing, performance engineering, optimization and heuristic search. 相似文献
16.
Optical burst switching (OBS) networks have been receiving much attention as a promising approach to build the next generation
optical Internet. In the bufferless DWDM switching technology, burst loss that should be minimized is the key design parameter.
One of the critical design issues in OBS network is how to plan the optimal routing path in order to minimize burst dropping
due to network resource contention. This study proposes the burst frequent-pattern tree (BFP-Tree) approach to pre-determine
a suitable routing path in the OBS network. The BFP-Tree approach essentially is a learning-based mechanism that is able to
determine a suitable transmission path from the historical network transaction data. The experiment results show that the
successful rates of routing paths obtained by the BFP-Tree approach are able to converge to those of the optimal results.
相似文献
Zen-Der ShyuEmail: |
17.
We consider the problem of joint congestion control and resource allocation in spatial-TDMA wireless networks. The design
problem is posed as a utility maximization problem subject to link rate constraints which involve both transmission scheduling
and power allocation. Starting from the performance limitations of a centralized optimization based on global network information,
we proceed systematically in our development of two distributed and transparent protocols that rely on local information only.
In the process, we introduce a novel decomposition method for convex optimization, establish its convergence for the utility
maximization problem, and demonstrate how it suggests a distributed solution based on TCP/AQM and incremental updates of the
transmission schedule. We develop a two-step procedure for finding the schedule updates and suggest two schemes for distributed
link scheduling and power control under realistic interference models. Although the final protocols are suboptimal, we isolate
and quantify the performance losses incurred by each simplification and demonstrate strong performance in examples.
相似文献
Mikael JohanssonEmail: |
18.
Sheng Huang Keping Long Xiaolong Yang Qianbin Chen Yun Li 《Photonic Network Communications》2009,18(1):49-54
Optical burst switching (OBS) is a promising switching paradigm for building the next generation optical internet. The proportional
differentiation model is very convenient for network operators to quantitatively adjust the quality differentiation among
service classes. To provide proportional differentiated services for OBS networks, a proportional differentiation scheme based
on batch scheduling is proposed in this article. The scheme adopts the batch scheduling idea to reserve data channel resources
for a batch of data bursts. It helps to decrease burst dropping probability. When some data bursts are unsuccessfully scheduled,
a preemption method is used to keep a proportional burst dropping probability among service classes according to the expected
burst dropping probability equations given by the proportional differentiation model. The scheme has low computational complexity.
Simulation results show that the scheme can provide proportional differentiated services and efficiently decrease the burst
dropping probability.
相似文献
Keping LongEmail: |
19.
In this article we describe a feedback-based OBS network architecture in which core nodes send messages to source nodes requesting
them to reduce their transmission rate on congested links. Within this framework, we introduce a new congestion control mechanism
called congestion control with explicit reduction request (CCERQ). Through feedback signals, CCERQ proactively attempts to
prevent the network from entering the congestion state. Basic building blocks and performance tradeoffs of CCERQ are the main
focus of this article.
相似文献
Farid FarahmandEmail: |
20.
Optical burst switching (OBS) is regarded as one of the most promising switching technologies for next generation optical
networks. Contention resolution of data bursts is a critical mission to implement practical OBS. The use of fiber delay line
(FDL) buffers has received a lot of attention as a fundamental but effective solution to resolve burst contention. Several
studies have investigated the way to achieve the optimal performance of FDL buffers at a single-node level. However, this
article studies how to achieve the best performance of OBS networks with FDL buffers under varying traffic condition at a
network level. For this purpose, we propose an adaptive load-aware burst assembly (ALBA) scheme, which adaptively adjusts
the size threshold of burst assembler optimized to the current network traffic load. A piggybacking method used to deliver
the traffic-load information from core nodes to ingress edge nodes accelerates the adaptiveness of the proposed scheme by
reducing the update time of the size threshold. The effectiveness of the ALBA scheme is proved by comparing with No-FDL case
and fixed size-threshold cases under changing traffic-load environment from extensive simulation tests.
相似文献
JungYul ChoiEmail: |