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A WDM Passive Optical Network Architecture for Multicasting Services

研 究 生：林澤賢指導教授：吳和庭 博士

能支援群播服務之分波多工被動式光纖網路的架構

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Outline

Motivations Backgrounds A novel WDM Passive Optical Network

Architecture The Proposed Multicast Algorithm Simulation results Scalability problem Conclusions Future works

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Motivations

Network Environments Combined PSC and AWG WDM Passive Optical Network

Downstream Multicast Transmission Unicast Transmission

To Design a Multicast Scheduling Algorithm Simple Efficient

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Backgrounds

Optical Devices PSC AWG

Passive Optical Networks TDM PON WDM PON SUCCESS-DWA PON

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Optical Device-PSC

The Passive Star Couple is a passive multiport device Wavelengths launched onto any input port are broadcast

to every output port

3 x 3

PSC

1 2 3 4` λ

1 2 3 4` λ

1 2 3 4` λ

1 2 3 4` λ

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Optical Device-PSC

The PSC is the preferred device to single-hop WDM networks broadcast-and-select single-hop WDM network TDM PON

Advantages Broadcast signal Low cost

Disadvantages Power loss Do not wavelength spatial reused

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Optical Device-AWG

The AWG is passive wavelength routing device The same wavelength into any input port are routed to different output

port This period of the wavelength response is called free spectral range

(FSR)

1 λ

1 2 3 4` λ

1 2 3 4

λ

λ

1 2 3 4

2 x 2

AWG

2 3 4`

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The application of AWG device

f1,f2,f3,f4

f1

f2

f3

f4

f2*

f1,f2,f3,f4* f1,f2,f3,f4

f2

f1,f2,f3,f4

f1

f2

f3

f4

f 1,f2,f3,f4

f1,f2,f3,f4

f1,f2,f3,f4

f1,f2,f3,f4

f1,f4,f3,f2

f2,f1,f4,f3

A

B

C

D

f3,f2,f1,f4

f4,f3,f2,f1

A B C D

a) 多工器 b) 解多工器

c) Add-drop 多工器 d) 頻寬路由器

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Optical Device-AWG

Advantages Static wavelength routing Wavelength spatial reused No power loss

Disadvantages No broadcast channel

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Passive Optical Network

In a PON, all components between the end users and the central office (CO) are passive, such as optical fibers and couplers TDM PON WDM PON SUCCESS-DWA PON

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The TDM PON

In a Time-Division-Multiplexing PON, end users share the bandwidth in time domain

In the CO, an optical line terminal (OLT) transmits the downstream traffic to optical network unit (ONU) and manages the upstream traffic flows from the ONUs

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The TDM PON

OLT1 2 1 3 1 2 1 3

ONU 1

ONU 2

ONU 3

User 1

User 2

User 3

1 1

2

3

OLT1 21 3

ONU 1

ONU 2

ONU 3

User 1

User 2

User 3

1 1

2

3

2

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The WDM PON

What’s is Wavelength-Division-Multiplexing At the same time, a single fiber can carry Indepe

ndent data streams on different wavelengths WDM PONs create point-to-point links betw

een the CO and end user, no shared wavelength

Advantages High Capacity Scalable

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SUCCESS-DWA PON Architecture

TL 1

TL 2

TL 3

TL 4

AWG

Splitter

Splitter

Splitter

Splitter

ONU 1

ONU 16ONU 17

ONU 32

ONU 33

ONU 48

ONU 49

ONU 64

TL X = Tunable LaserCH X = WDM filter

CH 1

CH 16CH 1

CH 16

CH 1

CH 16

CH 1

CH 16

1 2 3 4 5 6 7 8 61 62 63 64

λ

User channel 1 User channel 2 User channel 16

AWG channels

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Functional diagrams of the OLT and ONU

Dispatcher

TL

TL

AWGSchedulerDownstream

OLT

VOQ 1

VOQ 2

VOQ N

Opticaldemux

RX 1

RX K

Processingunit

Upstream traffic

QueueLD

RX

Upstream traffic

Downstream traffic

WDM filter

Up/downcombiner ONU

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Proposed WDM Passive Optical Network Architecture

Downstream – Splitter Upstream – Combiner

OLT AWG

Splitter/ Combiner

ONU 1

ONU 16ONU 17

ONU 32

ONU 33

ONU 48

ONU 49

ONU 64

OLT = Optical Line TerminalONU X = Optical Network UnitAWG = Arrayed Waveguide Grating

Splitter/ Combiner

Splitter/ Combiner

Splitter/ Combiner

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Downstream mode

OLT use four tunable lasers to transmit control message on control channel or data packet on any wavelength

Each ONU consists of a tunable receiver which allow them to receive control message on a control channel (or data on any wavelength)

The multicast packet is received by the ONUs attached to the corresponding splitter

Each splitter equally distributes all incoming wavelengths to all attached receivers.

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Downstream mode

TL 1

TL 2

TL 3

TL 4

AWG

Splitter

Splitter

Splitter

Splitter

ONU 1

ONU 16ONU 17

ONU 32

ONU 33

ONU 48

ONU 49

ONU 64

TR

ONUTL X = Tunable LaserTR = Tunable Receiver

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TL Timing Structure

Each TL transmits control message which corresponded to the ONUs of the same AWG output port in the control time

Each TL transmits data packet to reach all ONUs attached to the same AWG output port in the data time

A control packet consists of three fields, destination address, wavelength, and offset time

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TL Timing Structure

Wc Wc Wc Wc WcW4 W3 W3 W4 W1

Data TimeControl Time

t

Wc Wc Wc WcW3 W2 W3 W2 W3

Wc WcW2 W1 W2 W2 W2

Wc Wc Wc WcW1 W2 W4 W3 W4TL1

TL2

TL3

TL4

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Functional Diagrams of the OLT and ONU - Downstream mode

Dispatcher

TL

TL

TL

TL

AWGScheduler

Queue

Downstream

TR

OLT

FT

ONU

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Functional Diagrams of the OLT and ONU - Downstream mode

Dispatch Mechanism Sequential Random Short Queue First

The Criteria for whether to Partition Multicast Packets depend on Multiple AWG Outputs ? Receiver Collision ?

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The Proposed Multicast Algorithm

An All-Out Packet Is Defined to Be a Queued HOL Packet with All of Its Intended Recipients Free and at the same AWG output port in the Scheduling Time

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The scenario of multicast algorithm

The HOL packet of Queue 1 is all-out packet

1,10,2

Scheduler

Queue

10,25,26

13,12,2

19,9,3

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Simulation Parameters (Unicast)

The parameters are N = 64 ONUs The Tunable laser TLs = 4 Packet generation follows the Poisson arrival process Mean arrival rate = 0.48~4.32 packets/slot Bandwidth = 1Gbps Packet Size = 1518 bytes Time slot = 12 us The Simulation during 1000000 slot time TDM Four-TDM-PON DWA SUCCESS-DWA PON

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Unicast – Average Packet Delay

Average packet delay defined as the average time from the generation of a packet until the completion of the multicast transmission

Downstream Unicast Transmission

0.01

0.1

1

10

100

1000

10000

100000

0.48 0.96 1.44 1.92 2.4 2.88 3.36 3.84 4.32

Mean arrival rate (packets/slot)

Average packet delay(us)

DWA TDM WDM(Sequential) WDM(Random) WDM(Short)

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Simulation Parameters (Multicast)

Packet generation follows the Poisson arrival process

Mean arrival rate = 0.12~2.28 packets/slot Bandwidth = 1Gbps The time slot = 12us Packet size = 1518 bytes The destination nodes of a multicast packet

are randomly selected among all ONU Mean multicast throughput is defined to be the

mean number of All-Out packets in the average time slot

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Simulation Parameters

系統參數 說明 代表符號Number of TLs OLT 之可調式發射器個數 TL

Number of ONUs ONU 之個數 ONU

Mean Multicast Size

平均群播封包的大小 E[S]

D x D AWG AWG 的輸入與輸出端的個數

AWG

網路架構 說明

DWA SUCCESS-DWA PON

PON Short Queue First of WDM PON

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Mean multicast size E[S]=5.5

1

10

100

1000

10000

100000

1000000

10000000

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Multicast throughput (packets/slot)

Average packet delay (us) DWA AWG = 4 TL = 4 ONU = 64 PON AWG = 4 TL = 4 ONU= 64

Simulation Results (Multicast)

Comparison with different PON

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Simulation Results (Multicast)

Comparison with different Mean multicast size E[S]AWG = 4 TL = 4 ONU = 64

1

10

100

1000

10000

100000

1000000

10000000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Multicast throughput (packets/slot)

Average packet delay (us)

PON E[S]= 3 PON E[S]= 5.5 PON E[S]= 10.5 DWA E[S]= 3 DWA E[S]= 5.5 DWA E[S]= 10.5

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Scalability Problem

Expanding ONUs Expanding TLs of the OLT Comparisons with different AWG ports

4 x 4 AWG port 8 x 8 AWG port

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Expanding ONU

Mean multicast size E[S] = 5.5

1

10

100

1000

10000

100000

1000000

10000000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Multicast throughput (packets/slot)

Average packet delay (us)DWA AWG = 4 TL = 4 ONU = 64 DWA AWG = 4 TL = 4 ONU = 128

PON AWG = 4 TL = 4 ONU= 64 PON AWG = 4 TL = 4 ONU = 128

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Expand TL of the OLT (1/2)

AWG

Splitter

Splitter

Splitter

Splitter

ONU 1

ONU 16ONU 17

ONU 32

ONU 33

ONU 48

ONU 49

ONU 64

Splitter

Splitter

Splitter

Splitter

ONU 65

ONU 80ONU 81

ONU 96

ONU 97

ONU 112

ONU 113

ONU 128

TL 1

TL 2

TL 3

TL 4

TL 5

TL 6

TL 7

TL 8

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Expand TL of the OLT (2/2)

Mux

AWG

Splitter

Splitter

Splitter

Splitter

ONU 1

ONU 32ONU 33

ONU 64

ONU 65

ONU 96

ONU 97

ONU 128

TL X = Tunable LaserMux = Multiplexer

TL 1

Mux

Mux

Mux

TL 2

TL 3

TL 4

TL 5

TL 6

TL 7

TL 8

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Simulation results

Mean multicast size E[S] = 5.5

1

10

100

1000

10000

100000

1000000

10000000

0 0.5 1 1.5 2 2.5 3

Multicast throughput (packets/slot)

Average packet delay (us)

DWA AWG = 8 TL = 8 ONU = 128 PON AWG = 4 TL = 8 ONU = 128 PON AWG = 8 TL = 8 ONU = 128

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Conclusions

Proposed The Multicast Scheduling Mechanism for WDM Passive Optical Network

Compare our proposed WDM PON with SUCCESS-DWA PON

Scalability problem Study ONU FSR

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Future works

Keep solving the scalability problem The upstream issue Compare with the AWG based Single-

Hop WDM network and our proposed WDM network architecture

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THE END