The Design of power saving mechanisms in Ethernet Passive Optical Networks

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The Design of power saving
mechanisms in Ethernet Passive
Optical Networks
Yun-Ting Chiang
Advisor: Prof Dr. Ho-Ting Wu
2013.10.28
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Outline
Introduction
Optical-Fiber Network
Passive Optical Network (PON)
EPON
The Design of Power Saving mechanisms in Ethernet Passive
Optical Networks
Two energy-modes in ONU
Add doze mode in ONU
Improve three energy-modes in ONU
Interleaved Polling with Adaptive Cycle Time (IPACT)
Clockwise three energy-modes switching
Counterclockwise three energy-modes switching
Upstream scheduling
Downstream scheduling
Simulation result
Conclusion
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Passive Optical Network (PON)
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Passive Optical Network (PON)
Optical line terminal (OLT)
Optical network units (ONUs) or
Optical network terminals (ONTs)
Use broadcast on Downstream
Use TDMA on Upstream
All ONUs register to OLT with LLID
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EPON
REPORT and GATE message
REPORT
ONU to report its bandwidth requirements
OLT passes REPORT to the DBA algorithm
GATE
After executing DBA algorithm, OLT transmits
GATE down-stream to issue up to four
transmission grants to ONU
Transmission start time
Transmission length
Timestamp (used by ONU for synchronization)
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Interleaved Polling with Adaptive Cycle
Time (IPACT)
OLT maintain a Table with Byte and RTT
First grant, G(1), is set to some arbitrary value
In polling cycle n, ONU measures its backlog in bytes
at end of current upstream data transmission &
piggybacks the reported queue size, Q(n), at end of
G(n)
Q(n) used by OLT to determine next grant G(n+1) =>
adaptive cycle time & dynamic bandwidth allocation
If Q(n)=0, OLT issues zero-byte grant to let ONU
report its backlog for next grant
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The Design of Power Saving mechanisms in
Ethernet Passive Optical Networks
Two energy-modes in ONU
Add doze mode in ONU
Improve three energy-modes in ONU
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Two energy-modes in ONU
In L. Shi, B. Mukherjee, and S. S. Lee, "Efficient
PON with Sleep-Mode ONU: Progress, Challenges,
and Solutions," refer two energy-modes including
active and sleep modes. They separate high/low
priority packet.
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Early wake up
ONU can
receive GATE
msg
Because of Toverhead , ONU have wait 2.125ms to receive GATE msg. from OLT
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Lei Shi, Biswanath Mukherjee and SangSoo Lee’s research
Didn’t consider downstream high priority data delay
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Add doze mode in ONU
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Add doze mode in ONU
ONU Tx: off Rx:on
Downstream high priority data won’t trigger sleep
ONU wake.
Doze mode can make OLT send downstream data
earlier.
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Add doze mode in ONU
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Add doze mode in ONU : Weak point
Doze mode will implement even no downstream data.
Low doze mode utilization
Active mode can’t turn to doze mode when no
downstream data.
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Improve three energy-modes in ONU
Clockwise three energy-modes switching
Counterclockwise three energy-modes switching
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Clockwise three energy-modes switching
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Clockwise three energy-modes switching
Consider performance
A -> S
[1] No upstream and downstream data when OLT get ONUx’s REPORT.
A -> D
[2] No upstream data but has downstream data when OLT get ONUx’s REPORT.
S -> A
[3] Upstream high priority data coming
// Early wake up
S -> D
[4] Stay at sleep mode for consecutive Y clock
// variable Y protects downstream high priority data Y is maximum of downstream high
priority data delay.
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Clockwise three energy-modes switching
D -> A
[5] Stay at doze mode for consecutive Z clock || upstream high priority data coming
// Timer avoids upstream long low priority data delay
// variable Y、Z protects upstream low priority data Y + Z is maximum upstream
low priority data delay
p.s.
Active mode trigger: If report msg. request bandwidth = 0, means no upstream data.
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Counterclockwise
three energy-modes switching
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Counterclockwise
three energy-modes switching
Consider power saving
A -> S
[1] No upstream and downstream data when OLT get ONUx’s REPORT.
A -> D
[2] No upstream data but has downstream data when OLT get ONUx’s REPORT
S -> A
[3] Stay at sleep mode for Y clock || upstream high priority data coming
// variable Y protects downstream high priority data Y is maximum of downstream
high priority data delay.
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Counterclockwise
three energy-modes switching
D -> S
[4] Stay at doze mode for consecutive Z ms
// Force
// Timer avoids upstream long low priority data delay
// variable Y、Z protects upstream low priority data Y + Z is maximum upstream
low priority data delay
// Switch from Doze mode to Sleep mode is no delay so downstream high priority data
increase Y clock delay, it’s maximum of downstream high priority data delay
D -> A
[5] upstream high priority data coming
// early wake up
p.s.
Active mode trigger: If report msg. request bandwidth = 0, means no upstream data.
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Upstream scheduling
Using Limited service.
Limited service : OLT grants requested number of
bytes, but no more than MTW
OLT polling table increase ONU state.
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Downstream scheduling
Although downstream slot and upstream slot are
difference but there have some relationship.
Different from general EPON, because ONU[x] in
sleep mode, OLT can’t send downstream data.
Downstream scheduling need to be considered.
ONUs’ doze mode maybe overlap so OLT need to
select one of ONUs to send downstream data.
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Simulation Result
Clockwise three energy-modes switching
ONU = 16
ONU queue size 10MByte
EPON Frame size = 64Bytes ~ 1518 Bytes
Channel capacity = 1Gbps
Max rate = 100 * 1000 * 1000 = 100Mbps
Guard time = 5 * 10-6
Y : After 20ms the state from sleep to doze
Z : After 30ms the state from doze to active
Simulation time 3s
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Dynamic downstream loading
Upstream load:1 High = 99% Low = 1%
1,2
1
0,8
0,6
Active
Doze
Sleep
0,4
0,2
0
0,8 1,6 2,4 3,2
4
4,8 5,6 6,4 7,2
8
8,8 9,6 10,4 11,2 12 12,8 13,6 14,4 15,6 16
Downstream load
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Dynamic downstream loading
Upstream load:0.01 High = 50% low = 50%
1
0,9
0,8
0,7
0,6
0,5
Active
Doze
0,4
Sleep
0,3
0,2
0,1
0
0,8
1,6
2,4
3,2
4
4,8
5,6
6,4
7,2
8
8,8
9,6 10,4 11,2 12 12,8 13,6 14,4 15,6 16
Downstream load
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Dynamic upstream loading
Downstream load = 10 High = 99% low = 1%
1
0,9
0,8
0,7
0,6
0,5
Active
0,4
Doze
0,3
Sleep
0,2
0,1
0
Upstream load
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Dynamic upstream loading
Downstream load: 0.01 High = 50% low = 50%
1
0,9
0,8
0,7
0,6
Active
0,5
Doze
0,4
Sleep
0,3
0,2
0,1
0
upstream load
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Conclusion
In this study, power saving mechanisms focus on
reduce high priority downstream data delay in power
saving EPON.
In order to raise up doze mode utilization, we design
new three energy-modes switching mechanisms to
increase it.
All results discuss between power saving and
performance, it’s trade off. Maybe we can improve
traffic scheduling or switching mechanism for future.
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Reference
[1] Glen Kramer and Biswanath Mukherjee “IPACT: A Dynamic
Protocol for an Ethernet PON (EPON),” IEEE Communications
Magazine, February 2002.
[2] Lei Shi, Biswanath Mukherjee and Sang-Soo Lee “Energy-Efficient
PON with Sleep-Mode ONU: Progress, Challenges, and Solutions,”
IEEE Network March/April 2012 pp. 36-41.
[3] Jingjing Zhang and Nirwan Ansari “Toward Energy-Efficient 1GEPON and 10G-EPON with Sleep-Aware MAC Control and
Scheduling,” IEEE Communications Magazine February 2011 pp.
s34-38.
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Thanks for your listening
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