=Paper=
{{Paper
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|storemode=property
|title=Implementation and Evaluation of a Sleep-Proxy for Energy Savings in Networked Computers
|pdfUrl=https://ceur-ws.org/Vol-920/p68-sheme.pdf
|volume=Vol-920
|dblpUrl=https://dblp.org/rec/conf/bci/ShemeFA12
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==Implementation and Evaluation of a Sleep-Proxy for Energy Savings in Networked Computers==
https://ceur-ws.org/Vol-920/p68-sheme.pdf
Implementation and Evaluation of a Sleep-Proxy for
Energy Savings in Networked Computers
Enida Sheme Neki Frasheri Marin Aranitasi
Department of Computer Science Department of Computer Science Department of Computer Science
Polytechnic University of Tirana Polytechnic University of Tirana Polytechnic University of Tirana
enida.sheme@gmail.com neki.frasheri@gmail.com m_aranitasi@hotmail.com
ABSTRACT asleep. So, in our work we emphasize this by testing a real
In enterprise networks, idle desktop machines rarely sleep, system in an office environment, showing and highlighting the
because users and IT departments want them to be always differences between non-proxy system and proxy system
accessible. While some solutions have been proposed, few of network regarding their energy consumption.
them have been implemented even more evaluated in real In Section 2, we mention related articles, papers and
network environments. In this paper, we implement and evaluate publications regarding this area. In Section 3 we will give a
a sleep proxy system, based on existing proposed architecture preview of the design and implementation of Sleep Proxy server,
for this Proxy. how are all the components related to each other in Hardware
This system is tested in 6 different PC machines of a real and Software level. Section 4 describes the experimental
network. The results of the experiments show that machines can environment, also the tests regarding the power consumption
sleep almost 55% of the experimenting time (which is translated without and with Proxy server implemented in the experiment,
into energy savings) while maintaining their network in order to get an idea of energy savings this system can provide.
accessibility to user satisfaction. However, there is a need of The results of the experiments and their interpretation are given
“cooperation” between IT procedures and sleep proxy system in in section 5, where we emphasize the need of synchronization
order to gain better performance and thus less dissipated energy. between IT staff and the Proxy system in order to get the best
results. At last we come with our conclusions.
Keywords
Power consumption, energy savings, networked computers, 2. RELATED WORK
network traffic, proxying Ethernet adapter The Sleep Proxy idea was first introduced in 1998 by Kenneth
Christensen in an International Journal [9]. Although there were
some technologies such as “Wake on LAN” and “Advanced
1. INTRODUCTION Configuration and Power Interface Specification” in 90’s
There has been a lot of researches lately regarding the wasted regarding saving energy issue, due to some of their
energy consumed especially by the IT environment, [11], [3], disadvantages, there are no more researches in the area. Instead,
[6], [1]. One of the most frequent cases is that of office attention was back to Sleep Proxy in 2004 by Bruce Nordman
machines left on despite of user activity on them. [8]. An interesting paper comes in 2007 for an implemented
The focus of this paper is exactly enterprise’s PCs, the power Proxy specifically designed for Universal Plug and Play
management of which would save up significant energy. Protocol (UPnp) [12]. Later in 2007, Bruce Nordman and
The main reason PC users and IT administrators want to leave Keneth Christensen came with another work where they propose
PCs on all the time is they want to access them whenever they solution [10] for a Sleep Proxy which can manage protocols
want to, or whenever it is planned a broadcasting update or such as ARP, DHCP, ICMP. Another scheme similiar to Sleep
process. Among many ideas, lately the focus is back to Sleep Proxy comes in 2008 called Somniloquy [13]. It offers a
Proxy concept, which was first introduced in 1998 [9] and later hardware implementation of Sleep Proxy in a so-called
researched. A Sleep Proxy allows a PC to pass into a Sleep state, “gumstix”, thought as a predecessor of future NIC. We can also
meanwhile it preserves PC’s network presence and awakens it if mention [4]: Sleep Proxy as a standard of European Computer
necessary. The architecture of this Sleep Proxy system is Manufacturers Association in November 2009. Researches go
composed by a client which periodically updates the server with on and another paper of 2010’ [7], illustrates designing,
information it needs to represent this client while it is asleep, implementing and testing of a Sleep Proxy in Microsoft Offices.
and the server (Sleep Proxy) that based on a designed policy on
how to manage network traffic protocols, will eventually ignore 3. DESIGN AND IMPLEMENTATION
some packets, answer to some requests, and awake the sleeping ISSUES
computer for other packets. In this section we show some design and implementation issues
The aim of developing a Sleep Proxy system is to encourage based on previous known architecture of Sleep Proxy Server,
users to enable power management features, assuring them that expressed in papers such as [2], [8] and [9]. The Sleep Proxy
they can have access to their computers even when they are system is based on a client/server architecture where every client
can fall asleep, being represented on the network by the Sleep
BCI’12, September 16–20, 2012, Novi Sad, Serbia. Proxy server.
Copyright © 2012 by the paper’s authors. Copying permitted only for private and
academic purposes. This volume is published and copyrighted by its editors.
Local Proceedings also appeared in ISBN 978-86-7031-200-5, Faculty of Sciences,
University of Novi Sad.
68
3.1 Client Server Communication Protocol • 4 of them: Processor Intel(R) Core Duo CPU 2.0 GHz,
RAM 1 GB, HDD 160 GB, Operating System 32-bit
Based on the characteristics of what we want our Sleep Project
Windows XP, TFT screen
to do, we specify below the client server communication. That
means what will the server do and what will the client do in our • 2 of them: Processor Intel(R) Core Duo CPU 2.0 GHz,
system. RAM 1 GB, HDD 160 GB, Operating System 32-bit
The client will eventually: Windows 7.
The server has these parameters: Processor Intel(R) Core Duo
• provide to the proxy server necessary information that
CPU 2.4 GHz, RAM 2 GB, HDD 160 GB, Operating System
server will need in order to represent the sleeping computer
32-bit Windows 7.
on the network. This will be done by periodically (every 10
seconds) sending an INFO message that contains these In every client is installed Java JDK and executes the client.jar
data: PC_name, IP address, MAC address, Operating application, which is the client Proxy application. Meanwhile
System, state, local time the server executes the Server Proxy application. The network
• “request” to the proxy server to change his status to sleep topology is Bus.
when it is going to sleep. This will happen automatically by There will be held these experiments to test the Sleep Proxy
server when it doesn’t get an INFO message after 20 system. The first testing: we will measure the consumed energy
seconds (twice the time of default time set for periodic and the network traffic (number of packets) passing to them
sending of INFO) during the time 16:00 to 8:00 of the next day, for three
• notify the server whenever the client is awaked by any continuous days, providing so 3 samples for each computer,
event. This will happen by automatically sending INFO without “sleep proxy” implemented. The second testing, will
• know and process any waking packet that comes from the include the 7-th computer, the server Sleep Proxy, and we will
server (which means to support some kind of WoL measure the same parameters for 16 hours, in three days. So we
technology) will have 3 other samples for each of 6 client computers. Based
• optionally can configure the default time for periodic on the results of the experiments we will compare the energy
sending of INFO, IP address of server, communication port consumed and network traffic, also the time of each computer
with the server. The default values are set in the passed on sleeping state with Sleep Proxy system implemented,
programming code. which is automatically translated into energy savings.
The server will eventually:
• be listening to INFO messages from the clients and store 4.2 Measuring Tools
these data in a table 4.2.1 Joulemeter
• keep a list of tables to keep track and information about The power consumption is measured by a specific tool produced
computers on the network by Microsoft called Joulemeter. We will measure the power
• change status of a computer from Sleep to Awake in its list consumption for 16 hours, for 3 days.
whenever that clients notifies it is awaked (it gets INFO
messages) 4.2.2 Wireshark
• prevent any network traffic to wake the sleeping computer Wireshark is the program from which we will get information
in vain by ignoring or answering to these kind of packets about the network traffic in the experimental client machine, in
• wake up the sleeping computer by sending a WoL packet terms of number of packets, saved in generated .pcap files.
whenever there is a network traffic too important not to be
answered by the client itself 5. RESULTS AND INTERPRETATION
The first testing results regarding the power consumption and
3.2 Implementation Issues total number of packets are shown in Table 1 below.
Based on the survey of [11] regarding network chattering, we
decide to implement this reaction policy for the Proxy server:
• it will answer back to ARP requests, will send ARP probes Table 1: 3-day Average Power Consumption and total nr. of
broadcasts on the network when necessary packets without implemented proxy on the network
• wake up sleeping computer by sending WoL packet in case
of TCP requests toward that computer
• ignore all the others
Programming this system will need:
• Java RMI for building the client / server applications (as a
programming environment is chosen “Eclipse IDE for Java
Developers”, Version 3.5.2 “Helios Service Release”),
• Jpcap library (Java packet capturing) which serves for
capturing, analyzing and processing network packets.
4. EXPERIMENTS
4.1 Experiment Preview
The experiment environment is composed by 6 computers
clients and one server. 6 computers have these parameters:
69
As we can see from the table, Computer C1 and C6 have higher During the 16 experimenting hours, using a Sleep Proxy server,
power consumption and this happens because of the CRT screen it was provided a percentage of sleeping time in a range of 44%
that consumes more power. The same data of Table 1 are shown to 65%, with an average sleeping time of 8.71 hours, illustrated
in a graphical form in Figure 1. in Table 3 and Figure 3.
Table 3: Average and percentage of sleeping hours during
the 16 experimental hours with Sleep Proxy
Figure 1: Graphical representation of 3-day Average Power
Consumption and total number of packets without
implemented proxy on the network.
The results about the second testing, when Sleep Proxy is
implemented on the network, regarding power consumption and
total number of packets are shown in Table 2, also in a graphical
form in Figure 2:
Table 2: 3-day Average Power Consumption and total
number of packets with implemented proxy on the network
Figure 3: Percentage of experiment hours in sleeping or
awake state with implemented proxy.
Now using the formula Energy = Power * Time, we calculate
each of 6 computers * 16 experimental hours = energy
consumed (kWh) per each computer. It is computed that the
daily average energy consumption per computer is 1.97 kWh.
Translated in annual energy consumption, if 6 computers would
be left on from Monday to Thursday afternoons, it is computed
an average energy consumption of 376kWh per each computer,
or about 376 MWh for 1000 computers of a big company in a
year.
Meanwhile using the Sleep Proxy system on the experimental
network shows these calculated results:
Energy consumed = 3W * sleeping hours + Power consum. *
Awake hours
It is computed that, using Sleep Proxy, the daily average energy
consumption per computer is 0.92 kWh. In comparison to the
value just given above, without Sleep Proxy of 1.97 kWh, we
save energy up to 53%. So, computers with proxy consume 53%
less power than without proxy. The annual calculation would be
176 MWh for 1000 computers in a year.
The difference with and without proxy is approximately
208MWh, translated into 54.2% energy savings.
Figure 2: Graphical representation of 3-day Average Power The figures 4 and 5 show respectively the difference in a
Consumption and total number of packets with implemented graphical form of Daily Average energy consumed and Daily
proxy on the network. Average number of packets in the NIC by the client with and
without proxy.
70
of the Sleep Proxy system. We can mention here procedures and
routines such as backup, patches, automatic updates, scheduled
by the IT department. Of course, IT department policies and
schedules regarding these fields play a non-trivial role in Sleep
Proxy performance. Sleep Proxy is active during non-official
time (16-8 of the next day) so it would be much helpful from the
IT department to be synchronized with this system in order to
get the best results from Sleep Proxy.
7. REFERENCES
[1] Allan Chen “Berkeley Lab Researcher Leads Development
of a Standard to Reduce Energy Use of Computers
Connected to the Internet”.
[2] Bruce Nordman, Ken Christensen “Improving the Energy
Figure 4: Difference in daily average energy consumed by Efficiency of Ethernet-Connected: A Proposal for
the client with and without proxy. Proxying”, Version 1.0, September 2007.
[3] Chamara Gunaratne, Ken Christensen and Bruce Nordman
“Managing energy Consumption Costs in desktop PCs and
LAN switches with proxying, split TCP connections, and
scaling of link speed”, INTERNATIONAL JOURNAL OF
NETWORK MANAGEMENT, October 2005.
[4] ECMA Standards, “Final Draft, Proxzzzy for sleeping
hosts”; November2009,www.ecma-international.org
/publications/files/ECMA-ST/ECMA-393.pdf
[5] “EPA Announces New Computer Efficiency Requirements”
– October 2006,
http://yosemite.epa.gov/opa/admpress.nsf/4a3d7e51caf96c7
a85257359003f533e/113b0c0647fee41585257210006474f1
!OpenDocument
[6] Greg Shultz “Use Windows XP's power management
Figure 5: Difference in daily average number of packets in
features to lower energy bills”, November 2002,
the client NIC with and without proxy.
http://articles.techrepublic.com/510010878111054827.html
6. CONCLUSIONS [7] Joshua Reich, Michel Goraczko, Aman Kansal, Jitendra
The results of this paper highlights the importance of power Padhye – “Sleepless in Seattle No Longer”, Microsoft
management features application and encourage this by Research, Proceedings of the 2010 USENIX Conference,
evaluating a Sleep Proxy system, making a comparison of June 2010.
energy consumed between two situations: without Sleep Proxy [8] K. Christensen, C. Gunaratne, B. Nordman, and A. George,
implemented, and with Sleep Proxy implemented on the “The Next Frontier for Communications Networks: Power
network.
Management,” Computer Communications, Vol. 27, Nr. 18,
The system we implemented can provide significant energy
savings, assuring computers’s availability on the network and a f. 1758-1770, 2004.
high level of transparency for other computers of the network. [9] Kenneth J. Christensen, Franklin ‘Bo’ Gulledge – “Enabling
Due to our experiments, we calculate that in our system of 6 Power Management for Network-attached Computers”,
computers, daily average energy consumption in a Sleep Proxy International Journal of Network Management, Vol. 8,
system is 0.92 kWh per each computer. Compared to the daily Nr.2, pp. 120-130, 1998.
average energy consumption value without implemented Sleep [10] M. Allman, K. Christensen, B. Nordman, dhe V. Paxson,
Proxy, of 1.97 kW, the energy savings results up to 53%, so
“Enabling an Energy-Efficient Future Internet Through
computers in a Sleep Proxy environment consume 53% less
energy than the same computers in a Non-Sleep Proxy Selectively Connected End Systems,” Sixth Workshop on
environment. These values belong to only one computer on the Hot Topics in Networks (HotNets-VI), November 2007.
network, but as the size of the company grows the energy saving [11] Sergiu Nedevschi, Jaideep Chandrashekar, Junda Liu,
becomes more and more significant in an annual period, up to Bruce Nordman, Sylvia Ratnasamy, Nina Taft – “Skilled
hundreds of MWh. The energy savings is achieved by longer in the Art of Being Idle: Reducing Energy Waste in
sleeping time in the presence of a Sleep Proxy Server. In a non- Networked Systems”, NSDI Conference, April 2009.
Sleep Proxy environment, sleeping time is almost 0 hours.
[12] UPnP Low Power Architecture, Version 1.0, UPnP Forum,
Meanwhile the results of the experiments with Sleep Proxy
implemented, show that during 16 hours of experimental time, August 27, 2007.
the 6 computers stayed in sleeping time from 44% to 65% of [13] Yuvraj Agarwal, Steve Hodges, James Scott, Ranveer
the time, translated in 7.2 to 10.4 sleeping hours, from a total of Chandra, Paramvir Bahl, Rajesh Gupta “Somniloquy:
16 hours. Knowing that Sleep proxy is a system which is closely Maintaining Network Connectivity While Your Computer
related to other Software components, brings to the need for Sleeps”, 2008.
some Software policies that would help in a better performance
71