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Proceedings ArticleDOI

Performance comparison of scheduling algorithms for IPTV traffic over polymorphous OBS routers

TL;DR: This work proposes scheduling algorithms for the transmission of periodic channels using PATON, and studies the blocking probability observed by best-effort traffic, when such scheduling algorithms are used.
Abstract: Recent research in optical burst switched networks has proposed solutions to support subwavelength reservation for the periodic transmission of data bursts, which can coexist with conventional asynchronous bursts, bringing the polymorphous, agile and transparent optical networks (PATON) [1]. Thus, network operators can distribute IPTV channels to their customers, whereby they can use the spare bandwidth for the transmission of best-effort traffic, making use of the free gaps in between such periodic reservations. This work proposes scheduling algorithms for the transmission of periodic channels using PATON, and studies the blocking probability observed by best-effort traffic, when such scheduling algorithms are used.

Summary (2 min read)

1. INTRODUCTION

  • Of Dense Wavelength Division Multiplexing (DWDM) technique [2] has multiplied data transmissions capacities for optical equipment.
  • Furthermore, the network operator can use the gaps in between each TDM slot to send best-effort traffic.
  • Not only PATON, but other solutions allow the combination of periodic reservations and asynchronous traffic: Synchronous OBS [7], Synchronous-Stream OBS [8] and Wavelength-Routed OBS [9].
  • A preliminary analytical performance study with synchronous and asynchronous traffic is done in [7].
  • Section 5 shows the simulations and analytical results.

2. TRACE CAPTURE SYSTEM

  • This work intents to make a fair performance comparison among various scheduling algorithms for IPTV traffic in the most realistic scenario possible.
  • Figure 2 shows the architecture of the Trace Capture System.
  • The ADSL router receives all traffic for the user: Internet traffic and TV channels.
  • The trace analysis showed that the channel was encoded with MPEG-2 and its bit rate was around 4.16 Mbps.
  • These parameters correspond to the Standard Definition Television (SDTV) codification [10].

3. SCHEDULING ALGORITHMS FOR PERIODIC TRANSMISSIONS

  • As previously stated, PATON allows network operators to share network resources between periodic synchronous reservations and best-effort traffic.
  • Some algorithms can be used to schedule the periodic IPTV transmissions . First Fit (FF): This algorithm inserts all TV channels together in the first free wavelength.
  • Synchronous Shifted Round Robin (SSRR): SSRR is similar to SRR, with the difference that the reservation in each lambda is shifted Ton.
  • The reason is that this algorithm transmits the first Nch/M channels and, after this, it allocates the next reservation in the following wavelength.

4. PERFORMANCE ANALYSIS

  • The following makes use of the Erlang B loss formula to derive the blocking probability of the best effort data bursts transmitted in between the on periods of IPTV transmission.
  • Obviously, the Erlang B loss formula does not take into account the retroblocking effect of OBS networks (see [11]), which arises when the offset values are highly variable.
  • For simplicity, in the following analysis the authors assume that the offset values are either constant or with low variability, thus making the Erlang B loss formula a good approximation to the actual blocking probability.
  • The accuracy of such approximation is assessed in the experiments section.

5. RESULTS AND EXPERIMENTS

  • This section is split into three subsections.
  • Firstly, the authors define the most important scenario parameters.
  • Secondly, the authors study the blocking probability for the four algorithms with realistic values for the transmission of IPTV traffic.
  • In the third part, the authors compare the formula obtained in the analysis section and the simulation results.

5.1 Scenario definition

  • Let us briefly outline a few design guidelines for a network operator which is willing to provide IP Television (IPTV) service to its customers using PATON.
  • To simulate a realistic scenario, the authors will use the interarrival time of the Spanish IPTV provider trace (2.5 ms) and the bitrate (4.16 Mbps).
  • Using previously defined parameters, the Toff period for FF and RR algorithms is 2.3ms, and 2.475ms for SRR and SSRR algorithms (M=8).

5.2 Scheduling algorithms performance evaluation

  • Figure 5-A shows the burst blocking probability for the four scheduling algorithms when varying best-effort load.
  • In the light of the results, FF and RR algorithms achieve the best performance.
  • SRR performance is the lowest, since it creates “blind” areas assuring the blocking of the incoming bursts in Toff periods.
  • Ton periods between consecutive reservations improves the non-blocking probability considerably.
  • Therefore, an operator which wants to distribute IPTV traffic using PATON should schedule the synchronous traffic using the FF algorithm.

5.3 Analytical and simulations results comparison

  • The previous section showed that the worst scheduling algorithm is the Synchronous Round Robin (SRR) algorithm and the best one is the First Fit (FF).
  • This section presents a comparison between the analytical formulas compute for FF and SRR algorithms.
  • Figure 6-A illustrates the simulated and theoretical blocking probability for the FF algorithm when the burst length varies.
  • Figure 6-B illustrates the results for SRR.
  • Analytical and simulation results are very close and only, when D length is similar to Toff and load is higher to 50%, the formula does not fit.

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Repositorio Institucional de la Universidad Autónoma de Madrid
https://repositorio.uam.es
Esta es la versión de autor de la comunicación de congreso publicada en:
This is an author produced version of a paper published in:
ICTON Mediterranean Winter Conference, ICTON-MW 2007. IEEE, 2007. 1-6
DOI: http://dx.doi.org/10.1109/ICTONMW.2007.4446930
Copyright: © 2007 IEEE
El acceso a la versión del editor puede requerir la suscripción del recurso
Access to the published version may require subscription

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
This work has been partially funded by the Spanish Ministry of Science and Education under the project DIOR
(TEC2006-03246), and by the Comunidad Autónoma de Madrid under project e-Magerit (S-0505/TIC/000251).
The authors would also like to acknowledge the support from the European Union VI Framework Programme e-
Photon/ONe+ Network of Excellence (FP6-IST-027497).
Performance comparison of scheduling algorithms for IPTV
traffic over Polymorphous OBS routers
Víctor López, José Luis García-Dorado, José Alberto Hernández, Javier Aracil
Networking Research Group, Universidad Autónoma de Madrid,
Calle Francisco Tomás y Valiente 11, 28049 Madrid, Spain
Tel: (0034)914972268, Fax: (0034)914972235, e-mail: victor.lopez @uam.es
ABSTRACT
Recent research in Optical Burst Switched networks has proposed solutions to support subwavelength
reservation for the periodic transmission of data bursts, which can coexist with conventional asynchronous
bursts, bringing the Polymorphous, Agile and Transparent Optical Networks (PATON) [1]. Thus, network
operators can distribute IPTV channels to their customers, whereby they can use the spare bandwidth for the
transmission of best-effort traffic, making use of the free gaps in between such periodic reservations. This work
proposes scheduling algorithms for the transmission of periodic channels using PATON, and studies the
blocking probability observed by best-effort traffic, when such scheduling algorithms are used.
Keywords: Optical Burst Switching, IP Television, Service differentiation, CBR traffic.
1. INTRODUCTION
The introduction of Dense Wavelength Division Multiplexing (DWDM) technique [2] has multiplied data
transmissions capacities for optical equipment. Thanks to the latest advances in optical transmission, 25 Tbps
can be transmitted over the same fibre [3]. However, the reservation of one wavelength per user leaves unused
most of the bandwidth capacity of this lambda. Optical Burst Switching (OBS) technology increases the
utilisation level of the optical bandwidth. This is possible, because of aggregation of incoming packets into
bursts and their further all-optically transmission across the network [4], [5].
The most common OBS signalling is Just Enough Time (JET) protocol [6]. JET reserves in advance a
wavelength transmission time via a Burst-Control Packet (BCP). To configure the core nodes, BCPs are
transmitted an offset time ahead. In-advanced reservation allows the separation of network resources for services
with different QoS requirements. The proposal of Polymorphous, Agile and Transparent Optical Networks
(PATON) architecture [1] uses this resource separation to propose a unique framework to support all optical
services: lightpaths just like in Optical Circuit Switching (OCS), burst services (OBS) and Time Division
Multiplexing (TDM) circuits with subwavelength capacity.
A core Polymorphous OBS (POBS) node is illustrated in Figure 1. This node has to deal with a complete
wavelength reservation (denoted by 1), a TDM reservation (synchronous fixed time slots reserved, denoted by
2), and asynchronous best-effort bursts (single asynchronous reservations, denoted by 3).
Control Unit
OXC
2 2
3 3
1
2
3
λ
1
λ
2
λ
3
T
2 2 2
3 3
1
3
3
3
BCPs
Full wavelength reservation
TDM circuit reservation
Control Plane
Best-Effort Traffic
Figure 1: PATON architecture.

To provide these new services, the Burst Control Packets have got their attributes increased with respect to the
conventional OBS architecture. For instance, there are fields like the periodic reservation time, which is used
only for TDM services, while routing information is necessary for all services. Therefore, with the PATON
architecture, the same underlying network infrastructure can be used to support all kind of optical services.
For this work, we shall consider the IP Television (IPTV) service using PATON technology. Using OBS, the
provisioning of this service would require one BCP per TDM slot. Moreover, not all TDM slots are reserved
because of the blocking probability. Nevertheless, sending one PATON’s BCP, TDM circuit is established.
Furthermore, the network operator can use the gaps in between each TDM slot to send best-effort traffic.
Therefore, it is interesting to study the blocking probability given to such best-effort data bursts, assuming that
the TDM circuit is given preference. To the best of our knowledge, this study has not yet been done.
Not only PATON, but other solutions allow the combination of periodic reservations and asynchronous traffic:
Synchronous OBS [7], Synchronous-Stream OBS [8] and Wavelength-Routed OBS [9]. PATON is selected
because it covers the functionalities of all of them. A preliminary analytical performance study with
synchronous and asynchronous traffic is done in [7]. In this article, the authors carry out an analysis of SOBS
solution, but focused on the payload problem because of the transmission of small bursts. To solve this problem,
they define grooming algorithms both synchronous and asynchronous data bursts using Fiber Delay Lines
(FDLs) on attempts to maintain a high level of network utilisation. The authors study the throughput of both
types of traffic when different grooming policies are applied.
The reminder of this work is organised as follows: section 2 explains the IPTV traffic capture system. Section
3 defines the scheduling algorithms for the periodic transmissions. Section 4 calculates an analytical formula for
the computation of the blocking probability experienced by best-effort traffic. Section 5 shows the simulations
and analytical results. Finally, section 6 concludes this work with a brief discussion and future work.
2. TRACE CAPTURE SYSTEM
This work intents to make a fair performance comparison among various scheduling algorithms for IPTV
traffic in the most realistic scenario possible. To achieve this goal, it is absolutely necessary to obtain a detailed
characterization of the IPTV traffic that a service provider sends to its customers.
In this light, we have captured the traffic that a client of a Spanish IPTV service provider receives at his home
when he is watching a TV channel. Figure 2 shows the architecture of the Trace Capture System. Basically it
consists of a computer running Wireshark tool
1
, connected directly to an ADSL router. The ADSL router
receives all traffic for the user: Internet traffic and TV channels. Therefore, the Trace Capture System must be
able to filter and collect only IP TV traffic.
The capture process lasted 10 minutes and the trace size was about 300 MB. The trace analysis showed that the
channel was encoded with MPEG-2 and its bit rate was around 4.16 Mbps. These parameters correspond to the
Standard Definition Television (SDTV) codification [10]. Additionally we found that the IPTV traffic streams
were basically Constant Bit Rate (CBR) with packet interarrival times of 2.5ms. Thus, in the following, we shall
use these parameters in the simulation set.
Figure 2: Architecture of the trace capture system.
3. SCHEDULING ALGORITHMS FOR PERIODIC TRANSMISSIONS
As previously stated, PATON allows network operators to share network resources between periodic
synchronous reservations and best-effort traffic. However, some algorithms can be used to schedule the periodic
IPTV transmissions (Figure 3 and Figure 4). Let us define four scheduling policies:
1
http://www.wireshark.org/

First Fit (FF): This algorithm inserts all TV channels together in the first free wavelength. As the
IPTV traffic has priority over asynchronous traffic, IPTV reservation is always allocated in the first
lambda (Figure 3).
Round Robin (RR): This algorithm allocates reservations in the first free lambda, like FF. However,
RR stores the wavelength previously used, so the next search starts in the next lambda. Therefore, RR
reserves one time slot every T
off
+ T
on
in each lambda (Figure 3).
Figure 3: First Fit and Round Robin scheduling algorithms.
Synchronous Round Robin (SRR): SRR uses all lambdas when TV channels are transmitted. One
reservation is done in each wavelength so N
ch
/M channels are transmitted per slot (Figure 4).
Consequently, the T
off
period is greater than in the two previous algorithms.
Synchronous Shifted Round Robin (SSRR): SSRR is similar to SRR, with the difference that the
reservation in each lambda is shifted T
on
. The reason is that this algorithm transmits the first N
ch
/M
channels and, after this, it allocates the next reservation in the following wavelength. This algorithm
allows the use of all wavelengths, avoiding the “blind” areas that SRR creates (Figure 4). By “blind”
areas, we refer to those at which no data burst can be scheduled because of CBR traffic.
Figure 4: Synchronous Round Robin and Synchronous Shifted Round Robin algorithms.
4. PERFORMANCE ANALYSIS
The following makes use of the Erlang B loss formula to derive the blocking probability of the best effort data
bursts transmitted in between the on periods of IPTV transmission. Obviously, the Erlang B loss formula does
not take into account the retroblocking effect of OBS networks (see [11]), which arises when the offset values
are highly variable. For simplicity, in the following analysis we assume that the offset values are either constant
or with low variability, thus making the Erlang B loss formula a good approximation to the actual blocking
probability. The accuracy of such approximation is assessed in the experiments section.
The total probability theorem (eq. 1) takes into account the blocking probability of each case (“T
on
” and “T
off
period) times the probability of the best-effort data burst to actually arrive in each case-
)()(
ononBKoffoffBKBK
TPPTPPP
+
=
(1)
Once the blocking probability is defined in terms of the Erlang-B formula and T
on
and T
off
periods, we can easily
achieve the expression for the First Fit (eq. 2) and Synchronous Round Robin (eq. 3) algorithm.

First Fit algorithm:
),(),1( AME
TT
DT
AME
TT
DT
P
B
onoff
off
B
onoff
on
BK
+
+
+
+
=
(2)
Synchronous Round Robin:
),( AME
TT
DT
TT
DT
P
B
onoff
off
onoff
on
BK
+
+
+
+
=
(3)
5. RESULTS AND EXPERIMENTS
This section is split into three subsections. Firstly, we define the most important scenario parameters.
Secondly, we study the blocking probability for the four algorithms with realistic values for the transmission of
IPTV traffic. In the third part, we compare the formula obtained in the analysis section and the simulation
results.
5.1 Scenario definition
Let us briefly outline a few design guidelines for a network operator which is willing to provide IP Television
(IPTV) service to its customers using PATON. To simulate a realistic scenario, we will use the interarrival time
of the Spanish IPTV provider trace (2.5 ms) and the bitrate (4.16 Mbps). The number of channels sent by an
IPTV provider are in the range of 100 to 200, we assume N
ch
= 192 channels.
Once CBR parameters are defined, let us define ρ as the average best-effort input to the system, defined as:
M
D
λ
ρ
=
(1)
where λ is the number of arrivals per second, D is the burst length and M is the number of wavelengths.
Using previously defined parameters, the T
off
period for FF and RR algorithms is 2.3ms, and 2.475ms for SRR
and SSRR algorithms (M=8).
5.2 Scheduling algorithms performance evaluation
Figure 5-A shows the burst blocking probability for the four scheduling algorithms when varying best-effort
load. In the light of the results, FF and RR algorithms achieve the best performance. SRR performance is the
lowest, since it creates “blind” areas assuring the blocking of the incoming bursts in T
off
periods. The behaviour
of SSRR varies strongly with the burst length (Figure 5-B). When D T
on
, T
on
shifted between lambdas is
negligible in temporal terms, so SSRR performance is degraded. However, if D << T
on
, T
on
periods between
consecutive reservations improves the non-blocking probability considerably. In this case, SSRR performance is
closer to FF and RR.
1e-06
1e-05
0.0001
0.001
0.01
0.1
1
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Blocking Probability
rho
D=0.025 ms
FF
RR
SRR
SSRR
1e-06
1e-05
0.0001
0.001
0.01
0.1
1
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Blocking Probability
rho
D=0.125 ms
FF
RR
SRR
SSRR
1e-06
1e-05
0.0001
0.001
0.01
0.1
1
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Blocking Probability
rho
D=0.25 ms
FF
RR
SRR
SSRR
1e-06
1e-05
0.0001
0.001
0.01
0.1
1
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Blocking Probability
rho
D=0.5 ms
FF
RR
SRR
SSRR
0.01
0.1
1
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Blocking Probability
D (ms)
rho=0.5
FF
RR
SRR
SSRR
A. Best-effort load variation B. Burst length variation
Figure 5: Comparison of burst blocking probability.

Citations
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Journal ArticleDOI
TL;DR: This work shows how to extend the well-known Erlang fixed point procedure to evaluate the performance behavior of POBS networks, whereby asynchronous data bursts coexist with high-priority periodic TDM reservations.
Abstract: In polymorphous optical burst-switched (POBS) networks, the burst control packets (BCPs) of conventional just-enough-time based signalling OBS networks are given extended properties which enable them not only to reserve fixed time-slots for asynchronous data bursts, but also to allocate TDM reservations for periodic streams of data, and even a complete wavelength for high-bandwidth demanding services. This allows POBS to provide a flexible, yet transparent, approach for supporting the idiosyncrasies of today's most popular services over the same underlying network architecture. In POBS, the spare gaps in between synchronous TDM reservations can be used for the allocation of best-effort data bursts, leading to a more efficient utilisation of the optical capacity. This work shows how to extend the well-known Erlang fixed point procedure to evaluate the performance behavior of POBS networks, whereby asynchronous data bursts coexist with high-priority periodic TDM reservations. The performance evaluation algorithm is applied to a number of case scenarios, showing the benefits arisen due to the flexibility of POBS networks.

7 citations


Cites background or methods from "Performance comparison of schedulin..."

  • ...5 ms, as measured from a Spanish IPTV service provider (see [11] for further details), the and periods are given by...

    [...]

  • ...scheduling strategies have been analysed in detail in a previous work by the authors (see [11] for more details), showing the First Fit strategy to outperform over other ones....

    [...]

  • ...such previous study [11] provides an analytical approximation for the blocking probability experienced by asynchronous data bursts in such scenario, given by...

    [...]

  • ...Only the authors in [11] have addressed the performance evaluation of POBS in terms of the blocking probability experienced by best-effort data bursts, generated by a size-based burst assembler [6], when one of such synchronous reservations exist...

    [...]

Proceedings ArticleDOI
22 Jun 2009
TL;DR: The “offset based priority” and the “streamline effect” are investigated and a specific medium access protocol is proposed in order to preserve the isolation of transit bursts over ingress bursts and preserves the statistical multiplexing potential of OBS.
Abstract: Optical Burst Switching (OBS) has been proposed to increase the resource utilization achieved by Optical Circuit Switching (OCS), which is impaired by its coarse granularity. A crucial step toward OBS maturity deals with the feature of lossless guaranteed transfers. No contention resolution mechanism, even combined with efficient pro-active mechanisms has been able to provide such a guarantee so far. In this paper, we investigate further the “offset based priority” and the “streamline effect” to identify flow isolation patterns. We then propose a specific medium access protocol in order to preserve the isolation of transit bursts over ingress bursts. The isolation patterns are translated into an MILP optimization OBS model that performs routing and wavelength assignment (RWA-OBS). Using the routes obtained with RWA-OBS guarantees asynchronous loss-less transfers. It preserves the statistical multiplexing potential and the asynchronous nature of OBS, and thus addresses the drawbacks of WR-OBS and SOBS which were recently introduced in polymorphous OBS (POBS) (Qiao et al. 2006). Experimental results show the benefits of RWA-OBS over WR-OBS in terms of grade of service, while sidestepping the synchronization issues of SOBS with similar grade of service.

7 citations

Proceedings ArticleDOI
17 Nov 2009
TL;DR: The original RWA-OBS formulation is enhanced and an iterative greedy heuristic and a column generation approach are described to improve the computing time and the scalability of the model.
Abstract: Loss-less transfers are commonly associated with circuit switching: Circuit switching in all-optical networks (OCS) prevent from collisions by avoiding multiplexing below the wave-length granularity. Spectral multiplexing can be combined with time multiplexing in opaque networks at the expense of additional equipment (MSPP) and complex synchronization issues. Optical Burst Switching has been proposed a decade ago as a promising alternative to OCS: Its asynchronous nature and its arbitrary granularity open the possibility of statistical multiplexing, but it is not well suited to handle loss-less requirements. Wavelength routing and TDM can still be performed at the expense of a slight modification of the control plane, but those solutions override the OBS flexibility and avoid the statistical multiplexing. The RWA-OBS problem tends to solve the drawbacks of both WR-OBS and SOBS. Based on several properties related to the in advance reservation and the data plane transparency of OBS, it integrates particular cases where two flows can be multiplexed on a given wavelength in a genuine OBS fashion without loss. We first enhance the original RWA-OBS formulation and then describe an iterative greedy heuristic and a column generation approach to improve the computing time and the scalability of the model. Experiments are conducted on two topologies to illustrate the potential of RWA-OBS that can compete with SOBS without requiring synchronization. The new proposed methods are then compared in terms of computing times and qualities. The efficiency of the column generation approach allows the integration of an additional constraint to control the compromise between the burst insertion delay and the throughput.

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Proceedings Article
16 Apr 2013
TL;DR: This paper presents two novel cloning schemes for video delivery in Optical Burst Switching Networks that take into account the special characteristics of compressed video traffic and dramatically improve received video quality.
Abstract: This paper presents two novel cloning schemes for video delivery in Optical Burst Switching Networks. These schemes take into account the special characteristics of compressed video traffic and dramatically improve received video quality. Analytical and simulation results show up to 40% quality improvement without a substantial increase in the overall network traffic. The results show the strong dependency of these novel cloning schemes on the video traffic structure due to the coding mechanisms. Rules based on the GoP structure are presented to decide the frames to clone.

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References
More filters
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TL;DR: The general concept of OBS protocols and in particular, those based on Just-Enough-Time (JET), is described, along with the applicability ofOBS protocols to IP over WDM, and the performance of JET-based OBS Protocols is evaluated.
Abstract: To support bursty traffic on the Internet (and especially WWW) efficiently, optical burst switching (OBS) is proposed as a way to streamline both protocols and hardware in building the future generation Optical Internet. By leveraging the attractive properties of optical communications and at the same time, taking into account its limitations, OBS combines the best of optical circuit-switching and packet/cell switching. In this paper, the general concept of OBS protocols and in particular, those based on Just-Enough-Time (JET), is described, along with the applicability of OBS protocols to IP over WDM. Specific issues such as the use of fiber delay-lines (FDLs) for accommodating processing delay and/or resolving conflicts are also discussed. In addition, the performance of JET-based OBS protocols which use an offset time along with delayed reservation to achieve efficient utilization of both bandwidth and FDLs as well as to support priority-based routing is evaluated.

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TL;DR: This work investigates a high speed protocol called Just-Enough-Time (JET) based on a tell-and-go (TAG) protocol that can efficiently utilize the bandwidth, reduce the latency and provide data transparency.
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Journal ArticleDOI
TL;DR: A shaping scheme to set the offset, an important system parameter for OBS, between the successive data bursts of a given data stream and their associated control packets results in robust operation of the network and also facilitates traffic engineering.
Abstract: Wavelength-division multiplexing has emerged as an important physical layer technology Optical transmission provides a physical layer capable of carrying bits at the speed at the order of a gigabit per second Optical burst switching is proposed to overcome the shortcomings of conventional WDM deployment, such as lack of fine bandwidth granularity in wavelength routing and electronic speed bottlenecks in SONET/SDH We describe an architecture for IP network over the OBS WDM transmission core The use of MPLS-type technique for forwarding data bursts and the inclusion of a medium access control layer between the optical (WDM) and IP layers are the key ingredients of the proposed architecture In particular, the architecture is based on provisioning MPLS paths, also called label switched paths, of desired quality of service through the OBS WDM transmission core The MAC layer performs various OBS-specific functions, such as burst assembly, burst scheduling, and offset setting/traffic shaping While burst assembly and burst scheduling are relatively straightforward, we point out that the offset setting strategy has significant impact on the performance of IP network operating over OBS WDM core We describe a shaping scheme to set the offset, an important system parameter for OBS, between the successive data bursts of a given data stream (label switched path) and their associated control packets This scheme results in robust operation of the network and also facilitates traffic engineering Guidelines are provided for implementing various IP QoS mechanisms in the optical backbone using OBS

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TL;DR: In this article, the authors demonstrate record 25.6-Tb/s transmission over 240 km using 160 WDM channels on a 50GHz grid in the C+L bands.
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"Performance comparison of schedulin..." refers background in this paper

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Journal ArticleDOI
TL;DR: A new network architecture called polymorphous, agile, and transparent optical networks (PATON) is proposed, which uses polymorphous optical burst switching (POBS) to seamlessly integrate different signaling, switching, and reservation schemes.
Abstract: This article presents a vision for the emerging integrated optical networks to meet various traffic requirements and design criteria. To address the shortcomings in today's GMPLS over wavelength-routed optical networks, a new network architecture called polymorphous, agile, and transparent optical networks (PATON) is proposed. PATON uses polymorphous optical burst switching (POBS) to seamlessly integrate different signaling, switching, and reservation schemes. The main features of PATON, along with its benefits as well as design and implementation challenges, are also described. Finally, both qualitative and quantitative performance comparisons of POBS with the two representative IP/GMPLS/OCS approaches are provided

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"Performance comparison of schedulin..." refers background in this paper

  • ...This article proposes the used of PATON for the distribution of IPTV traffic by a network provider....

    [...]

  • ...PATON is selected because it covers the functionalities of all of them....

    [...]

  • ...As previously stated, PATON allows network operators to share network resources between periodic synchronous reservations and best-effort traffic....

    [...]

  • ...Let us briefly outline a few design guidelines for a network operator which is willing to provide IP Television (IPTV) service to its customers using PATON....

    [...]

  • ...For this work, we shall consider the IP Television (IPTV) service using PATON technology....

    [...]

Frequently Asked Questions (2)
Q1. What are the contributions mentioned in the paper "Performance comparison of scheduling algorithms for iptv traffic over polymorphous obs routers" ?

In this paper, the authors proposed the use of PATON for the distribution of IPTV traffic by a network provider. 

In future work, the authors shall analyse this solution not only for the transmission of one TDM stream reservation, but for multiple stream reservations simultaneously.