Transcript An Introduction to Optical Burst Switching（OBS）

A WDM Passive Optical Network Architecture for
Multicasting Services
Student：Tse-Hsien Lin
Teacher：Ho-Ting Wu
Date：2005.05.31
Outline
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Background
Motivations
A WDM Passive Optical Network
Architecture
The Proposed Multicast Algorithm
Simulation
Future work
Conclusions
Reference
Background
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PON
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TDM PON
WDM PON
Passive Optical Network
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In a PON, all components between the end users
and the central office (CO) are passive, such as
optical fibers and couplers
The TDM PON
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In a TDM PON, end users share the
bandwidth in time domain
In the CO, an optical line terminal (OLT)
transmits the downstream traffic to the
end users and manages the upstream
traffic flows from the end users
The TDM PON
The WDM PON
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What’s is WDM
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At the same time, The fiber can carry
Independent data streams on different
wavelengths
WDM PONs create point-to-point links
between the CO and end user, no sharing
wavelength
Advantage
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Scalable
High Capacity
Motivations
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Network Environments
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Downstream
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WDM Passive Optical Network
Wavelength Spatial Reused
Multicast Transmission
Unicast Transmission
To Design a Multicast Scheduling Algorithm
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Simple
Efficient
Scalable
Arrayed Waveguide Grating
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The AWG is a wavelength-routing device
Every second wavelength is routed to the same
output port
This period of the wavelength response is called
free spectral range (FSR)
λ
λ
1234
1 2
3 4`
2x2
λ
1234
AWG
λ
1 2
3 4`
SUCCESS-DWA PON Architecture Previous Works
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TL = Tunable laser
CH X = Thin-film WDM filter
Functional diagrams of the OLT and ONU
Previous Works
A WDM Passive Optical Network
Architecture
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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.
A WDM Passive Optical
Network Architecture
ONU 1
TL 1
Splitter
ONU 16
ONU 17
TL 2
Splitter
ONU 32
ONU 33
AWG
TL 3
Splitter
ONU 48
ONU 49
TL 4
Splitter
ONU 64
TL Timing Structure
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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 four fields,
destination address, guard time of each
destination, wavelength, and offset time
TL Timing Structure
TL1 Wc
W1
Wc
W2
Wc
W4
W3
TL2
W2
Wc
W1
Wc
W2
W2
TL3 Wc
W3
W2
Wc
W3
Wc
W2
Wc
W3
TL4 Wc
W4
W3
Wc
W3
Wc
W4
Wc
W1
Wc
Wc
W4
W2
t
Control
Guard
Time
Data
TL Timing Structure
4s
TL 1
2s
Splitter
ONU 4
1s
AWG
ONU 1
ONU 16
TL1
ONU16
ONU4
ONU1
Control
Guard
Time
t
Data
Function Diagrams of the OLT and
ONU
TL
TL
Downstream
Dispatcher
AWG
Scheduler
TL
TL
OLT
Queue
FT
TR
ONU
Function Diagrams of the OLT
and ONU
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Dispatch packet
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Sequence
Random
Short Queue First
The Scheduler Multicast Algorithm was
satisfied
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Partition or without Partition
Receiver Collision
The Proposed Multicast Algorithm
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An All-out Packet Is Defined to Be
a Queued Packet with All of Its
Intended Recipients Free and at
the same AWG output port in the
Scheduling Time
Select a HOL Packet at
Queue
Check the TLs
available?
Restart at next time Slot
No
The scheduler has finished
TLs assignment
Yes
Is the HOL packet a
All-Out Packet?
No
Yes
Yes
Partition the idle
destinations.
Check the destinations
of HOL packet in the
same AWG output
port?
No
Check the destinations of HOL
packet are idle?
Yes
No
Partition the max number of
destinations of HOL packet at the
same AWG output port
Partition the idle and the max number
of destinations of HOL packet at the
same AWG output port
No
Yes
Yes
Partition the idle
destinations.
Check the destinations
of HOL packet in the
same AWG output
port?
No
Check the destinations of HOL
packet are idle?
Yes
No
Partition the max number of
destinations of HOL packet at the
same AWG output port
Partition the idle and the max number
of destinations of HOL packet at the
same AWG output port
Update new intended destination for the HOL packet
Assign TL to the HOL packet
Check Next Queue
The scenario of multicast algorithm
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1,10,2
10,25,26
Scheduler
13,12,2
19,9,3
Queue
The HOL packet of
Queue 1 is all-out
packet
Simulation (Unicast)
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The parameters are N = 64 ONUs
The Tunable laser TLs = 4
Packet generation follows the Poisson
arrival process with parameter λ =
0.04~0.36
The time slot = 12us
The Simulation during 1000000 slot time
TDM  Four-TDM-PON
DWA SUCCESS-DWA PON
Simulation (Unicast Packet Delay)
Average Packet Delay(us)
DWA
TDM
WDM(Sequence)
WDM(Random)
WDM(Short)
100000
10000
1000
100
10
1
0.1
0.01
0.04
0.08
0.12
0.16
0.2
0.24
0.28
0.32
0.36
Mean Arrival Rate
Simulation (Unicast Queue Depth)
DWA
TDM
WDM(Sequence)
WDM(Random)
WDM(Short)
Average Queue Size(slots)
1.00E+03
1.00E+02
1.00E+01
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
0.04
0.08
0.12
0.16
0.2
0.24
0.28
0.32
0.36
Mean Arrival Rate
Simulation (Multicast)
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The parameters are N = 64 ONUs
The Tunable laser TLs = 4
Packet generation follows the Poisson arrival
process with parameter λ = 0.02~0.18
The time slot = 12us
The destination nodes of a multicast packet are
randomly selected among all ONU
The ONUs in the multicast size S are randomly
chosen from the uniform distribution [1,5]
The Simulation during 250000 slot time
Simulation (S = 5 Packet Delay)
DWA
WDM(Sequence)
WDM(Random)
WDM(Short)
Average Packet Delay (us)
10000000
1000000
100000
10000
1000
100
10
1
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
Mean Arrival Rate
Simulation (S = 5 Queue Depth)
DWA
WDM(Sequence)
WDM(Random)
WDM(Short)
Average Queue Size(slots)
10000
1000
100
10
1
0.1
0.01
0.001
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
Mean Arrival Rate
Proposed Multicast Scheduling
Algorithms – LookBack Mechanism
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Search for an All-out Packet in the Input
Queue up to the Lookback Length L
14,40,50
1,10,2
15,18,24 39,44,47
10,25,26
2,4,6
17,33,40
2,49,45
Queue
2,44,33
20,25,50
Scheduler
1,10,2
1,10,2
31,25,26 17,23,30
31,42,40 52,45,59
Length L = 5
63,2,7
13,12,2
23,45,46
Simulation (Multicast Length)
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The parameters are N = 64 ONUs
The Tunable laser TLs = 4
Packet generation follows the Poisson arrival process
with parameter λ = 0.02~0.18
The time slot = 12us
The destination nodes of a multicast packet are
randomly selected among all ONU
The ONUs in the multicast size S are randomly chosen
from the uniform distribution [1,5]
The LookBack Length L =
1,2,3,4,5,10,15,20,100,1000,10000,∞
The Simulation during 250000 slot time
Multicast Length L =1~5 Packet Delay
Average Packet Delay(us)
DWA
WDM(Sequence)
WDM(Lookback_1)
WDM(Lookback_3)
WDM(Lookback_4)
WDM(Lookback_5)
WDM(Lookback_2)
10000000
1000000
100000
10000
1000
100
10
1
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
Mean Arrival Rate
Length L =10,15,20,100,1000,10000,Infinite
Packet Delay
WDM(Lookback_10)
WDM(Lookback_15)
WDM(Lookback_20)
WDM(Lookback_1000)
WDM(Lookback_10000)
WDM(Lookback_Infinite)
WDM(Lookback_100)
Average packet delay(us)
100000
10000
1000
100
10
1
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
Mean Arrival rate
Future work
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Performance Key
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Packet delay
Receiver throughput
Conclusion
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Proposed The Multicast Scheduling
Mechanism for WDM Passive Optical
Network
Reference
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Ho-Ting Wu, Po-Hsin Hong, and Kai-Wei Ke, “On the
Multicast Scheduling Mechanisms for Interconnected WDM
Optical Network”, IEEE GLOBECOM 2003
Martin Maiser, Michael Scheutzow, and Martin Reisslein, “The
Arrayed-Waveguide Grating-Based Single-Hop WDM Network:
An Architecture for Efficient Multicasting”, Select Areas in
Communications, IEEE Journal , November 2003
Yu-Li Hsueh, Matthew S. Rogge, Wei-Tao Shaw, and Leonid
G. Kazovsky, “SUCCESS-DWA: A Highly Scalable and CostEffective Optical Access Network”, IEEE Optical
Communication August 2004
Glen Kramer and Gerry Pesavento, “Ethernet Passive Optical
Access Network (EPON): Building a Next-Generation Optical
Access Network”, IEEE Communications Magazine February
2002