Power savings provided by elastic optical networks
considering yearly traffic fluctuations
8th CEF Networks Workshop
Prague, Czech Republic
15th of September 2014
Ioan Turus
Outline
• Introduction
– Energy efficiency in ICT
– Global traffic forecasts
– Green networking
– Predictable traffic fluctuations
• Proposed traffic model
• Energy reduction strategies
• Control plane implementation
• Implementation and results
• Conclusions
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Energy efficiency in ICT
• The ICT industry accounts for
approx. 2% of global CO2 emissions,
a figure equivalent to aviation – Gartner 2007”
• “The share of electricity demand for ICT purposes
is almost 11% of the overall
final electricity consumption in Germany”
• “The ICT sector produces between 2% and 3%
global greenhouse emissions annually”
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Global traffic forecasts
[1] Cisco VNI, 2014
• 3x traffic increase between 2013 and 2018
4/17
Green networking
[2] Rhee, ICNC, 2012
5/17
Predictable traffic fluctuations and growth
• NORDUnet – The overlay network of Nordic National Research and
Education Networks
• NORDUnet traffic with Customers
– Day/night fluctuations
– Weekend drops
– Yearly growth
max
avg
min
100%
54%
16%
60%
[3] http://stats.nordu.net
6/17
Proposed traffic model
• Predictable fluctuations
– Diurnal and weekly fluctuations
• Yearly traffic growth
– Traffic growth within one connection
7/17
Energy reduction strategies
(I)
• On/Off (Sleep mode) of OE devices:
– Transponders (TRX)
– Regenerators (REG) – back-to-back transponder configuration
• 100 G PDM-QPSK
8/17
ON
IDLE
OFF
Power(TRX)
350 W
8W
0W
Power(REG)
700 W
16 W
0W
Energy reduction strategies
(II)
• Data-rate adaptation
• Elastic transponder/regenerator
– 25, 50, 75, 100 Gbps datarate configuration
Payload
(Gbps)
SR
(GBd)
MF
Reach
(km)
Power (W)
100
28
PDM-QPSK
1200
350
75
28
21
PS-QPSK
PDM-QPSK
1800
1200
350
255
50
28
14
PDM-BPSK
PDM-QPSK
2500
1200
350
206
25
28
14
7
SP-BPSK
PDM-BPSK
PDM-QPSK
3000
2500
1200
350
206
189
TABLE I. Elastic transponder power consumption
9/17
Energy reduction strategies
(III)
• Modulation Format (MF) adaptation
zzz…
100Gb/s
50Gb/s
TRX
Ch. Power: 700W
1400W
350W
REG
700W
50Gb/s
100Gb/s
TRX
350W
50Gb/s PDM-BPSK
100G PDM-QPSK
100G PDM-QPSK
• Symbol Rate (SR) adaptation
50Gb/s
100Gb/s
TRX
Ch. Power: 824W
1400W
350W
206W
100G
PDM-QPSK14
28GBd
GBd
50G PDM-QPSK
• Mixed (SR+MF) adaptation
10/17
100Gb/s
50Gb/s
REG
700W
412W
TRX
50G
100GPDM-QPSK
PDM-QPSK14
28GBd
GBd
350W
206W
Control plane implementation
• Automatic node configuration based on RSVP-TE signaling and a policy controller
• RSVP-TE used to:
– Set-up, tear-down Lambda LSPs according to the power state of OE devices
• Policy controller
– Decides on reconfiguration and/or recovery
– Provides the necessary information to the GMPLS control plane
11/17
Implementation
• Reference topology: NORDUnet and GEANT topologies
• Three types of demands equally distributed:
– 50, 75 and 100 Gbps (peak capacity)
• MIT (Mean inter-arrival time) of 1.6h
• Holding time of 38h
– Total load of 24 Erlangs
• 80 wavelengths
12/17
Scenario definition
MF
SR
Scenario 1
(Fixed)
fixed (100G)
fixed (100G)
Scenario 2
(MF)
adapt
fixed
Scenario 3
(SR)
fixed
adapt
Scenario 4
(Mixed)
adapt
adapt
TABLE I. Scenario definition
13/17
Results – Power consumption NORDUnet
• MF lower power (REGs placed in mode OFF)
– Peaks given by diurnal and weekly fluctuations (…from day 150)
• SR even lower power (symbol-rate adaptation)
– Higher peaks given by diurnal and weekly fluctuations
• Mixed - lowest power consumption
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Results – Power consumption GEANT
• MF lower than SR in this case
– Mainly due to long spans and higher need for regeneration
• Mixed - still the lowest power
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Results – Power savings
Average power savings
normalized to baseline
[%]
60,0
NORDUnet
50,0
GEANT
48,9
45,7
42,4
42,7
40,0
50,9
34,4
30,0
20,0
10,0
0,0
MF
SR
Energy reduction strategy
16/17
Mixed
Conclusions
• Traffic increase
overprovisioning
increased power consumption
• Periodical and predictable traffic variation in core networks
• Energy saving strategies based on:
– Sleep-mode of OE devices
– Data-rate adaptation (MF, SR and mixed)
•
50% energy savings for both networks in Mixed scenario
• MF outperforms SR in large footprint networks (e.g. GEANT)
• SR only is preferred in small networks due to less complex signaling
17/17
Thank you!
Ioan Turus
[email protected]
[email protected]
+45 31627817
Find me on:
18/17
Acknowledgements
-
Annalisa Morea and Dominique Verchere (Alcatel-Lucent Bell Labs) for guidance and valuable
feedback during the external stay at Alcatel-Lucent Bell Labs France.
-
Elastic Optical Networks Project (Celtic EO-Net) for valuable data regarding elasticity.
-
GreenTouch consortium for valuable input with regards to energy efficiency strategies.
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