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1.
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: |
2.
By taking advantage of statistical multiplexing gain in the burst level, optical burst switching (OBS) technology enables
optical Internet to handle huge volume of data in an efficient manner without requiring optical buffers in the optical domain.
However, when congestion builds up in the optical network core, large amount of data might be lost. In this article, we propose
an efficient optical burst control algorithm that operates based on the awareness of future burst traffic condition to eliminate
the effect of congestion reaction delay. The proposed algorithm takes advantage of multiple statistics to improve the estimation
accuracy.Through performance evaluation, it is verified that the proposed algorithm proactively controls inbound burst traffic
so that the OBS network can stay in a stable traffic condition while keeping the network throughput high.
相似文献
Myungsik YooEmail: |
3.
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: |
4.
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: |
5.
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: |
6.
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: |
7.
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: |
8.
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: |
9.
A new fault-management method using congestion-avoidance routing for optical burst-switched networks 总被引:1,自引:0,他引:1
Yurong? Huang Jonathan?P.?Heritage Biswanath?Mukherjee 《Photonic Network Communications》2008,16(2):117-125
Optical burst switching (OBS) has been proposed as a promising technique to support high-bandwidth, bursty data traffic in
the next-generation optical Internet. This study investigates a new fault-management framework for an OBS network. In an OBS
network, burst-loss performance is a critical concern. In OBS, the data-burst transmission is delayed by an offset time (relative
to its burst control packet (BCP), or header), and the burst follows its header without waiting for an acknowledgment for
resource reservation. Thus, a burst may be lost at an intermediate node due to contention, which is generally resolved according
to the local routing and bandwidth information. The routing table maintained in each OBS node is generally pre-computed and
fixed to forward the data bursts. Such a static forwarding feature might have limited efficiency to resolve contentions. Moreover,
a burst may be lost and the network may be congested when a network element (e.g., fiber link) fails. Therefore, for reliable
burst transport, we develop dynamic routing approaches for preplanned congestion avoidance. Our goal is to proactively avoid
congestion during the route-computation process, and our approach employs wavelength-channel utilization, traffic distribution,
and link-distance information in the proposed objective functions for routing. Two update mechanisms for maintaining a dynamic
routing table are presented to accommodate bursty data traffic. Based on our routing mechanisms, we also propose a new congestion-avoidance-and-protection
(CAP) approach, which employs a primary route and a group of backup routes for each node pair against failures and congestion.
The performance of the proposed protection strategy using congestion-avoidance routing is demonstrated to be promising through
illustrative numerical examples.
相似文献
Biswanath MukherjeeEmail: |
10.
Igor M. Moraes Rafael P. Laufer Daniel de O. Cunha Otto Carlos M. B. Duarte 《Photonic Network Communications》2009,18(1):65-76
This article proposes the load-level-based admission control (LLAC) mechanism in order to provide service differentiation
for optical burst-switched networks. The LLAC mechanism admits bursts of a given service class according to the network load
and a class-associated parameter. Based on this parameter, called load level, the proposed mechanism differentiates the burst blocking probability experienced by each service class. We develop an analytical
model for the proposed mechanism and evaluate its performance for different configurations through mathematical analysis.
The results show that the load-level-based mechanism reduces the blocking probability of high-priority bursts by two orders
of magnitude or more depending on the analyzed scenario. In addition, compared to other similar mechanisms, the load-level-based
mechanism effectively differentiates the services in all analyzed configurations, requires less states in optical burst switching
(OBS) nodes, and does not suffer from priority inversion.
相似文献
Otto Carlos M. B. DuarteEmail: |
11.
Li-Mei Peng Kyoung-Min Yoo Kyeong-Eun Han Young-Chon Kim 《Photonic Network Communications》2008,15(3):213-225
Optical burst switching (OBS) has been proposed as a new optical switching paradigm for the next generation Internet due to
its flexibility and feasibility compared to OCS and OPS. Moreover, serving as a backbone that interconnects a number of access
networks, OBS ring topologies have been a good choice for solving the current metro gap problem between core network and access
network owning to its simplicity and scalability. In this paper, we provide an insight into the OBS ring network that consists
of nodes using TT–TR (Tunable Transmitter–Tunable Receiver). The node architectures with TT–TR may make efficient use of network
resources even though traffic pattern, such as IP traffic with self-similarity dynamically change, and can support good expandability.
However, all nodes share the limited network resources. This may result in contention such as wavelength contention and transceiver
contention leading to burst loss. In order to use the shared network resources fairly and efficiently as well as reducing
the resource contention, we focus on the design of medium access control (MAC) protocols based on multiple tokens. Each token
is allocated to one wavelength to denote the accessibility of that wavelength, i.e., once the token is captured, the corresponding
wavelength can be used to transmit a burst. As tokens hold the key for using wavelengths to transmit bursts, token management
including the token release time is crucial in the proposed MAC protocols. Thus, two kinds of multiple-token based MAC protocols
with different token release times are proposed: token release after transmitting burst (TRTB) and token release after transmitting
control header (TRTC). Each of them is classified into two schemes called TRTB/TRR and TRTB/RCA and correspondingly TRTC/TRR
and TRTC/ RCA. RCA stands for receive collision avoidance. The target is to increase the performance while reducing the processing
overhead at each node. The performance of the TRTB and TRTC protocols are evaluated and compared in terms of queuing delay,
burst loss rate, and channel utilization by OPNET simulation. The effects of various design parameters are also investigated
through simulation in order to evaluate their scalability. In all the proposed schemes, tokens are just used to denote the
accessibility of each wavelength. Finally, as an alternative, we also propose a new scheme based on the TRTC protocol called
TRTC/CAT (collision avoidance by tokens) to avoid contention by using tokens.
相似文献
Young-Chon KimEmail: |
12.
An analytical model is derived to evaluate the performance of an optical switch using a feed-forward fiber delay line (FDL)
per output for contention resolution. Two different forwarding algorithms for the switch are presented and evaluated: a simple
forwarding algorithm (SFA) that is easier to implement, and an enhanced algorithm that provides better performance in terms
of both packet loss probability and packet delay. The analytical model can be utilized with both packet and burst switching
schemes to characterize the performance of the proposed architecture. Results show that the proposed architecture reduces
the packet loss probability compared to that without FDLs. Finally, the same architecture is shown to be capable of supporting
Quality of Service (QOS).
相似文献
Anura Jayasumana (Corresponding author)Email: |
13.
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: |
14.
The negative impact of cascaded wavelength conversions has been largely ignored in optical burst switching performance evaluations.
When optical bursts are transmitted all optically from source to destination, each wavelength conversion performed along the
lightpath may cause some signal-to-noise deterioration. If the distortion of the signal quality becomes significant enough,
the receiver would not be able to recover the original data. In this paper we examine the performance degradation when an
upper bound on the number of wavelength conversions that a signal can go through is enforced. We refer to this constraint
as conversion cascading constraint. We propose a novel proactive routing scheme under this constraint that considers the instantaneous link congestion at the
moment when the bursts arrive. It has three major advantages: (1) utilize the same offset times for the same node pairs while
providing dynamic routing without using any fiber delay lines (FDL); (2) decrease burst loss probability to a great extent;
(3) mitigate unfairness among the bursts with different hop counts, which is even worse under the conversion cascading constraint
if without any special treatment. We also extend the proposed mechanism to embrace a variant of regulated deflection routing
which can further improve network performance.
相似文献
Guifang LiEmail: |
15.
In the past years, several signaling protocols were proposed for OBS networks and the most popular one is the Just-Enough-Time
(JET) protocol. JET not only efficiently utilizes the network capacity, but also effectively reduces the end-to-end transmission
delay. However, the most critical defect of JET is its intrinsic deficiency: Fairness. The fairness problem is a traditional
problem common to various kinds of networks. It results in a phenomenon that bursts with a shorter number of hops are generally
favorized and hence deteriorates the network utilization as well. In this article, we investigate this problem and propose
a fair channel scheduling algorithm as a solution. Usually there is a tradeoff between fairness and blocking performance.
Accordingly, the objective of our scheme is to achieve a balance between the two conflicting metrics as much as possible.
In our scheme, each burst is associated with a dynamic priority which is defined by several characteristics of the burst.
When contention occurs, the proposed scheme picks the preferable burst and drops the other one according to their priorities.
From simulation results, we observed that the proposed scheme could improve fairness without causing significant reduction
in dropping performance. Furthermore, it increases the effective link utilization as well.
相似文献
Ching-Fang HsuEmail: |
16.
Daniel Morató Javier Aracil Juan Pedro Fernández-Palacios Óscar González de Dios Jesús-Felipe Lobo Poyo 《Photonic Network Communications》2008,15(2):159-169
This article presents capacity planning rules for the control plane of all-optical networks featuring GMPLS and RSVP-TE as
a connection setup protocol. As per RSVP standard, a refresh message mechanism is incorporated to RSVP such that the state
is periodically refreshed on a link per link basis. We provide analytical expressions for the bandwidth and buffer sizes to
be provided such that no flows are torn down due to lack of refresh messages. Our findings show that small buffers (several
KBytes) suffice to sustain the signaling load for as much as 400 RSVP flows per link, with the simplest RSVP refresh mechanism
(neither using link bundling nor acknowledgments). On the other hand, we also find the packet drop probability per link for
a given network topology for the case that the flow survival probability is larger than a given threshold. We provide numerical
examples based on the COST 239 european network topology and real RSVP traffic traces from early-commercial switching equipment.
相似文献
Jesús-Felipe Lobo PoyoEmail: |
17.
In TCP over OBS networks, consecutive multiple packet losses are common since an optical burst usually contains a number of
consecutive packets from the same TCP sender. In this paper, we first present a new theoretical method to analyze the behavior
of Reno when consecutive multiple packet losses occur. Results of the analysis indicate that even a small number of consecutive
multiple packet losses can force Reno to timeout. Then we propose B-Reno, a newly designed TCP implementation that can overcome
Reno’s inefficiency in dealing with consecutive multiple packet losses over OBS networks and can avoid the shortcomings of
New-Reno and SACK. Results of comprehensive simulations indicate that B-Reno over OBS networks can achieve a performance better
than Reno and New-Reno, and that it can also achieve a performance similar to that of SACK. Moreover, B-Reno only needs some
simple modifications to New-Reno at the sender’s protocol stack, and thus has less difficulty in deployment and less protocol
complexity than that of SACK.
相似文献
Sheng WangEmail: |
18.
Pedro Reviriego Anna Maria Guidotti Carla Raffaelli Javier Aracil 《Photonic Network Communications》2008,16(1):61-70
Loss modeling of asynchronous optical burst switches with shared wavelength converters is considered. An exact analysis based
on continuous time Markov chains is proposed and validated by comparison with simulation for balanced and unbalanced traffic.
A computationally efficient approximated analysis is also proposed and compared with the exact model to find applicability
conditions. Approximate loss performance evaluation is presented for ranges of values which are not tractable either by simulation
or exact analysis.
相似文献
Javier AracilEmail: |
19.
In optical wavelength-division multiplexing (WDM) networks, traffic can be unevenly distributed across the network causing
inefficient utilization of resources. To solve this problem, an improved soft preemptive (SP) scheme is proposed by considering
dynamic resource distribution to deal with the uneven network utilization. A novel unevenly distributed traffic model in cross-time-zone
networks is also presented to evaluate the efficiency of the new scheme. Compared with other schemes such as normal shortest
path first (SPF) routing and wavelength conversion (WC), the new proposed scheme results demonstrate significantly better
performance with respect to the network utilization and overall network blocking probability.
相似文献
Nan HuaEmail: |
20.
Maciej Jan Zawodniok Sarangapani Jagannathan 《International Journal of Wireless Information Networks》2007,14(4):251-263
In this paper, two novel energy-efficient rate adaptation schemes are presented. The proposed protocols use the Distributed
Power Control (DPC) algorithm to predict the channel state and determine the necessary transmission power which optimizes
the energy consumption. The first proposed rate adaptation scheme heuristically alters the modulation rate to balance the
energy-efficiency and the required throughput which is estimated with queue fill ratio. Moreover, the back-off scheme is incorporated
to mitigate congestion and reduce packet losses due to buffer overflows thus minimizing energy consumption. Consequently,
the nodes will conserve energy when the traffic is low, offer higher throughput when needed and save energy during congestion
by limiting transmission rates. The second rate adaptation scheme employs dynamic programming (DP) principle to analytically
select modulation rate and a burst size to be used during transmission. The proposed quadratic cost-function minimizes the
energy consumption while alleviating network congestions and buffer overflows. The proposed DP solution renders a Riccati
equation ultimately providing an optimal rate selection. The simulation results indicate that an increase in throughput by
96% and energy-efficiency by 131% is observed when compared to other available protocols, for example Receiver Based AutoRate
(RBAR).
相似文献
Sarangapani JagannathanEmail: |