1. Energy Efficient Ethernet An Overview
Mike Bennett Lawrence Berkeley National Lab

2. Ethernet Alliance as an incubator for EEE
Agenda
What is Energy Efficient Ethernet (EEE)?
How we got this far
Progress
What’s next?
Ethernet Alliance as an incubator for EEE

3. What is EEE? An idea An IEEE 802.3 Study Group
Reduce energy consumption during periods of low link utilization
Low hanging fruit
Minimizes impact on industry
Minimizes impact on standard
An IEEE Study Group
Formed in November 2006 to study the idea
Technical and economic feasibility
Compatibility and distinct identity
Broad market potential

4. But, how did we get to this point?
Things to be studied
Rapid PHY Selection
Switch to a lower speed (power) PHY during low link utilization
How to minimize transition time?
How to avoid thrashing between speeds?
Interaction with higher-layer protocols
Link utilization on servers
Interaction with control policy
But, how did we get to this point?

5. The road to EEE Tutorial given in July 2005 to IEEE 802
Bruce Nordman and Ken Christensen discuss the problem and possible ways to solve it
They propose the idea of Adaptive Link Rate (ALR)
This includes a control policy
This raises awareness within IEEE 802
Gauge interest between July ’05 and July ’06
ALR whitepaper posted on EA site August ’06
CFI team forms in August ’06

6. The CFI – identify the problem
“Big IT” – all electronics
PCs/etc., consumer electronics, telephony
Residential, commercial, industrial
200 TWh/year
$16 billion/year
Nearly 150 million tons of CO2 per year
Roughly equivalent to 30 million cars!
Numbers represent U.S. only
One central baseload power plant (about 7 TWh/yr)
PCs etc. are digitally
networked now — Consumer
Electronics (CE) will be soon

7. The CFI – more about the problem
“ Little IT” — office equipment, network equipment, servers
97 TWh/year
3% of national electricity
9% of commercial building electricity
Almost $8 billion/year
TWh/year
Network Equipment 13
Servers 12
PCs / Workstations 20
Imaging (Printers, etc.) 15
Monitors / Displays 22
UPS / Other 16
… However
Old data (energy use has risen)
Doesn’t include residential IT or networked CE products
Note: Year 2000 data taken from Energy Consumption by Office and Telecommunications Equipment in Commercial Buildings--Volume I: Energy Consumption Baseline Roth et al., 2002 Available at:

8. The CFI – even more about the problem
Unrestrained IT power consumption could eclipse hardware costs and put great pressure on affordability, data center infrastructure, and the environment.
Source: Luiz André Barroso, (Google) “The Price of Performance,” ACM Queue, Vol. 2, No. 7, pp , September (Modified with permission.)

9. The CFI - motivation to start EEE
Electric Utility Rebates
Appliances …
HVAC systems …
Lighting …
… PC power supplies (2005)
… Server computers (2006) …
Reference:
PG&E (California) provides rebates for more energy-efficient servers

10. EEE – motivation April 19, 2006 “Green Grid” formed
“A group of technology industry leaders form The Green Grid to help reduce growing power and cooling demands in enterprise datacenters
Energy Efficiency gets U.S. congressional recognition
July 12, 2006 House Resolution 5646 passes
“To study and promote the use of energy efficient computer servers in the United States”
Green500 Supercomputer list created Nov. ‘06
To “take energy efficiency into account when ranking supercomputers”
Using Flops/watt (total system power) as the metric

11. EEE – motivation Energy Star The market for Energy Efficient Ethernet
Requirements coming in 2009
“All computers shall reduce their network link speeds during times of low data traffic levels in accordance with any industry standards that provide for quick transitions among link rates”
The market for Energy Efficient Ethernet
Driven by customer’s desire to save energy costs
Ethernet is used in markets where saving energy is crucial
Accelerate deployment for new applications
Enables use of incentives by energy industry
Ultimately these translate to increased demand

12. The CFI – possible energy savings
Results from (rough) measurements — all incremental AC power
— measuring 1st order
Typical switch with 24 ports 10/100/1000 Mb/s
Various computer NICs averaged

13. The CFI – possible solution
Desktop-to-switch links
Are mostly idle
Lots of very low bandwidth “chatter”
High bandwidth needed for bursts
Bursts are often seconds to hours apart
Server links are also often not fully utilized
Higher speed links offer more opportunity to save energy
This is an area where more data is needed
Evidence of low utilization (desktop users)
LAN link utilization is generally in range 1 to 5% [1, 2]
Utilization for “busiest” user in USF was 4% of 100 Mb/s
[1] A. Odlyzko, “Data Networks are Lightly Utilized, and Will Stay That Way”, Review of Network Economics, Vol. 2, No. 3, pp , September 2003.
[2] R. Pang, M. Allman, M. Bennett, J. Lee, V. Paxson, and B. Tierney, “A First Look at Modern Enterprise Traffic,” Proceedings of IMC 2005, October 2005

14. The CFI – possible solution
Snapshot of a typical 100 Mb FE link
Shows time versus utilization (trace from Portland State Univ.)
Typical bursty usage
(utilization = 1.0 %)

15. The CFI – possible solution
Control policy determines when to transition data rate
RPS can support many different control policies
Need to consider but not define
Trade-off of energy saved versus packet delay
Energy savings achieved by operating at low data rate
Delay occurs during transition from low to high data rate
Must prevent link from thrashing
Control policy runs
on both ends of the link
switch
desktop PC
link
Control policy can be
based on queue length
thresholds

16. The CFI – possible solution
Sequence
Device A
Device B
Request
inhibit frame transmission
Acknowledge
inhibit frame transmission
change link speed
change link speed
~1 ms
establish new data rate
allow frame transmission
allow frame transmission
Time

17. The CFI – possible solution
Snapshot of a typical Ethernet link with simulated RPS
Mean packet delay with RPS is 0.67 ms
Mean packet delay without RPS is 0.12 ms
Utilization-threshold policy is used
Switching time: 1ms
Data rates: 100 and 10 Mb/s
Low/High thresh: 0KB and 32KB

18. The CFI – Benefits of EEE
1 Gb/s
Most NICs and most energy to be saved
Substantial benefits for homes and offices
Battery life benefit for notebooks
10 Gb/s (copper)
Reduces power burden in data centers
Reduces cooling burden in data centers
May increase switch/router port capacity
Generally…
Provides real economic benefit through energy savings

19. The CFI – potential savings identified
Assume 100% adoption (U.S. Only)
Residential
PCs, network equipment, other
1.73 to 2.60 TWh/year
$139 to $208 million/year
Commercial (Office)
PCs, switches, printers, etc.
1.47 to 2.21 TWh/year
$118 to $177 million/year
Data Centers
Servers, storage, switches, routers, etc.
0.53 to 1.05 TWh/year
$42 to $84 million/year
These figures do not include savings from cooling/power infrastructure
Total: $298 to $469 million/year

20. EEE - progress November Plenary Meeting (CFI) January Interim Meeting
33 supporters
15 from EA member companies
73 attendees
Passed 65 – 2 – 6
Many EA members in the room
January Interim Meeting
Met for almost 2 days
27-30 people attended per day
most were EA members
Heard several presentations
Update on control policies and impact to higher layer protocols
Open questions to the study group regarding scope

21. EEE - progress January Interim Meeting What’s next?
Presentations (continued)
“Strawman” proposal for 5 criteria and objectives
Update on candidate protocols
Impact on clause 28 (auto-negotiation)
Defined some terms
Took several straw polls
People took action items
What’s next?

22. EEE - what’s next? Preparing for March
Several people have offered to present
More simulations on control policy
Technical feasibility of Rapid PHY selection
Alternatives to Rapid PHY selection
Work related to Clause 28 (auto-negotiation)
A look at RPS for backplanes

23. EEE - what’s next? Preparing for March Ultimately preparing for PAR
What we still need
Traces from networks in different markets
Server network utilization
Home network utilization
Consumer electronics network utilization
How to communicate with upper layers?
Don’t want a network melt-down because of RPS
Economic feasibility of building EEE PHYs
Further study on broad market potential
Ultimately preparing for PAR
Where does the Ethernet Alliance fit in this?

24. EEE/EA – Technology Incubation
How did EEE get this far?
ALR Whitepaper posted on EA site
CFI Team and supporters
Mostly EA members
First study group meeting contributors and participants
EA Mission
The mission is to promote industry awareness, acceptance, and advancement of technology and products based on both existing and emerging IEEE 802 Ethernet standards and their management.

25. EEE/EA – Technology Incubation
Marketing Activities
Proactive cohesive messaging to external target audiences
Press
Most recently interviewed with CMP/Information Week to promote EEE
Arranged by the EA
Planning to form an EEE technical subcommittee
When the time is right
Bottom line
The EA has been there to help us be successful
Membership has its benefits

26. EEE/EA – summary
EEE is a classic case of technology incubation by the EA
EA support helped to keep EEE moving in the right direction
CFI preparation
EA marketing support is raising industry awareness
Press
The Ethernet Alliance will be there for us
When we need a place for consensus building among members
When the time comes for testing and demonstrating interoperability

27. Thanks!
Questions or comments?