Dynamic Bandwidth Allocation on TDMWDM Passive Optical Networks

1
Dynamic Bandwidth Allocation on TDM/WDM Passive
Optical Networks

• Ahmad Dhaini
• Prof. Chadi Assi
• Prof. Abdallah Shami

2nd Workshop on Optimization of Optical Networks,
April 14-15 2005
2
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

3
What is PON?

• PON called sometimes first mile or last mile
  is the evolutionary solution for bottleneck
  problem in broadband access networks.
• PON is a point-to-multipoint optical network with
  no active elements in the signals path from
  source to destination. The elements used in PON
  are all passive (combiners, couplers, and
  splitters).

4
What is PON?

• One Optical Line Terminal, resides in the Central
  Office that is connected to the backbone network
• Multiple Optical Network Units that connects to
  the OLT by a single wavelength channel, and are
  connected to the back-end users.
• Ethernet is an inexpensive technology that was
  applied to PON to get cost effective bandwidth.

5
PON Topologies
6
PON Advantages

• Longer distances between central offices and
  customer premises.
• Minimizes fiber deployment in both the local
  exchange and the local loop.
• Allows for downstream video broadcasting.
• No need of installing multiplexers and
  demultiplexers in the splitting locations.
• Easy upgrades to higher bit rates or additional
  wavelengths.

7
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

8
EPON Architecture
9
Multi-Point Control Protocol (MPCP)

• IEEE Standard
• OLT sends a GATE (grant) message in the
  downstream channel to the ONU, in which
  transmission information (start time,
  transmission length) are included.
• ONU sends a REPORT (request) message in the
  upstream to the OLT at the end of its
  transmission to notify the OLT of its buffering
  queue status.

10
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

11
Time Division Multiplexing EPON
12
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

13
Bandwidth Allocation Algorithms

• To Arbitrate the transmission between ONUs
• WMAX maximum transmission window size
• Vi transmission window size requested by ONU
• Wi transmission window size granted to ONU
• N Number of ONUs
• R Line rate (bps)

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Bandwidth Allocation Schemes

• Fixed Slot Assignment
• Wi Wmax
• Dynamic Bandwidth Allocation
• Limited
• Wi MIN Vi , WMAX
• Gated
• Wi Vi
• Constant Credit Wi MIN Vi Constant
  ,WMAX
• Linear Credit Wi MIN Vi Constant
  ,WMAX
• Elastic Wi MIN Vi ,NWMAX - ? Wj

15
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

16
Why WDM?

• Huge and Fast Growth of Internet, thus the need
  to deploy more ONUs.
• Continuous increase in the demand for bandwidth
• Tremendous success of Wavelength Division
  Multiplexing (WDM) technology in backbone network

17
WDM-PON ArchitectureFixed Tranceivers
ONU1- m
RxTx
Splitter/Combiner
Optical Fiber
TxRx TxRx
OLT
Users
k Wavelengths
ONUm-n
Rx Tx
Users
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WDM-PON Architecture Tunable Lasers
ONU1
Rx
Splitter/Combiner
Optical Fiber
TxRx TxRx
OLT
Users
k Wavelengths
ONUn
Rx
Users
Tunable Laser
19
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

20
TDM/WDM DBA

• DBA will now handle both Time Wavelength
• 4 Different Schemes can be applied
• Static WDM, Fixed TDM Algorithm
• Static WDM, Dynamic TDM Algorithm
• Dynamic WDM, Fixed TDM Algorithm
• Dynamic WDM, Dynamic TDM Algorithm
• Time Slot Assignment, as mentioned, depends on
  the ONU bandwidth demand
• Wavelength Assignment , will be dependent on the
  Traffic Load on each ONU (High Load or Low Load)

21
TDM / WDM PON
Guard Time
Run WDM-DBA
Tx 1
G1
G2
G3
G4
G1
G2
OLT
Rx 1
R1
Data
R2
Data
Tx 2
G3
G4
OLT
Rx 2
R3
Data
R4
Data
Tx 1
R1
Data
ONU1
Rx 1
G1
Tx 1
ONU2
R2
Data
Rx 1
G2
Tx 1
ONU3
R3
Data
G3
Rx 1
Tx 1
R4
Data
ONU4
Rx 1
G4
22
Simulation Parameters
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Static WDM-Dynamic TDM EQUAL LOAD
2 Wavelengths 1 Wavelength
Packet Delay
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Static WDM-Dynamic TDM EQUAL LOAD
2 Wavelengths 1 Wavelength
Packet Loss Rate
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Static WDM- Fixed vs. Dynamic TDMBalanced Load
2 Wavelengths
Move Statically Some High Load ONUs to transmit
on a wavelength with Low Load ONUs to balance the
Load on each channel.
Buffering Queue Behavior of Low Load ONU
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Static WDM- Fixed vs. Dynamic TDMBalanced Load
2 Wavelengths
Buffering Queue Behavior of High Load ONU
27
Dynamic WDM- Dynamic TDM

• Our current work is to move Dynamically ONU
  Transmission from one wavelength to another Using
  Tunable Lasers within the same time cycle.
• All Wavelengths are shared by all ONUs.
• This algorithm is still under Implementation

28
Outline

• Passive Optical Network
• Ethernet PON
• Time Division Multiplexing EPON
• Bandwidth Allocation Algorithms
• Wavelength Division Multiplexing PON
• TDM/WDM DBA
• Conclusion Future Work

29
Future Work Conclusion

• WDM Benefits
• WDM-TDM Dynamic Bandwidth Algorithm
• Dynamic WDM Dynamic TDM is expected to give
  better results.
• Future Work
• Quality of Service Support
• Let the OLT allocates both Wavelength and Time
  slot based on QoS Traffic Load .

30
Thank You!

• Thank You!

Ahmad Dhaini a_dhaini_at_ciise.concordia.ca Prof.
Chadi Assi assi_at_ciise.concordia.ca Prof.
Abdallah Shami ashami_at_eng.uwo.ca
2nd Workshop on Optimization of Optical Networks,
April 14-15 2005