Final Report (Small Routers, L2 Switches) by Router, etc.
Evaluation Standard Subcommittee, Energy Efficiency
Standards Subcommittee of the Advisory Committee for
Natural Resources and Energy

Router, etc. Evaluation Standard Subcommittee had deliberations on the evaluation
standards for manufacturers and importers (hereinafter, referred to as “manufacturers”)
of routers and switches, concerning the energy consumption efficiency of these products.
Then, the final report was prepared as follows.
This report covers small routers and L2 switches which had been discussed so far.
Deliberation on large routers and L3 switches will be carried on under this subcommittee.
I.

Small routers

1. Target Scope (See Attachment 1)
Among routers whose effective transmission rate is 200Mbit/s or lower (100Mbit/s orlower for wireless routers), those having the following characteristics are covered:• Not having VPN (Virtual Private Network) function; and• Having 2 or fewer lines in case they have VoIP (Voice over Internet Protocol)
function.
2. Details of Evaluation Standards for Manufacturers(1) Target fiscal year (See Attachment 2)
Fiscal year 2010
(2) Target standard values (See Attachment 3)
Concerning small routers to be shipped by a manufacturer for the domestic market
in the target fiscal year, for each category in the table below, the manufacturer has tomake sure that the value obtained by weighting and averaging energy consumption
efficiency (power consumption) measured according to (3) with the number of shipped
units shall not exceed the target standard value.

1

WAN side

LAN side

Target standard values

interfaceinterface(Power consumption: W)

A

Ethernet *1

4.0

BWith VoIP

5.5

Category

2.4GHz band transmission
P = (0.10*X2) + 3.95GHz band transmission

Ethernet *1

P = (0.15*X5) + 3.9
2 wave simultaneous transmission

With wirelessCP = (0.10*X2) + (0.15*X5) + 5.1
X2: 2.4GHz wireless output (mW/MHz)
X5: 5GHz wireless output (mW/MHz)D
E

Ethernet *1

7.4

With VoIP

7.4

With wireless

8.8

ADSL

F

*1 Ethernet: Registered trade mark by Fuji Xerox Co., Ltd. Standard of LAN.

(3) Energy consumption efficiency measurement method (See Attachment 4)
Energy consumption efficiency shall be the power consumption (W) measured by thefollowing method.
{ Measurement configuration• It shall be a configuration so that the maximum throughput will be achieved at themeasurement packet length of 1500 bytes.
• The measurement shall be made after removing any parts and stopping any
functions within the scope of the router’s maximum configuration, as long as they
are removable or stoppable without interrupting its basic performance/function.
• It is acceptable to conduct the measurement using a cascading connection
configuration for ports.
• It shall be a configuration so that the unit under measurement will route received
packets.
• Within the scope of the router’s maximum configuration, ports not used in themeasurement are allowed to be link-down.
• Small routers with wireless LAN interface are measured with the following
configuration.

2a) It shall be a configuration so that only wireless transmission direction (download
side: packets sent from WAN side to wireless LAN side) is measured.
b) If a router is equipped with multiple wireless LAN interfaces which can operate
simultaneously, it shall be configured so that all of them will operate
simultaneously.
c) It shall be a configuration where data compression function and adjusting
function for output power, etc. are stopped.
d) Link rate shall be the maximum link rate of the unit under measurement.
{ Measurement packet• IP packets for unicast communication shall be used.
• Measurement packet length (PDU (Protocol Data Unit) length of Layer 3) shall be
1500 bytes.
• Header of each layer shall comply with IEEE802.3, IETF or other equivalent
standards.
• Data patterns of headers are discretional.

Data patterns of measurement packets

shall be all 0.
• Bit rate (bit/s) and total number of packets sent to the unit under measurement
during the measurement are also allowed to be the required minimum to achieve themaximum performance.
{ Measurement conditions• Ambient temperature shall be between 16°C and 32°C.

However, for small routerswith wireless LAN, the temperature range from 0°C to 40°C is also acceptable.
• Supply voltage shall be the rated input voltage (100V or 200V) ±10% in the case ofusing AC power source.

It shall be between DC−57V and DC−40.5V in the case ofusing DC power source.
• Frequency of AC power source shall be the rated frequency.
• Maximum throughput and power consumption shall be measured while staying in a
steady state.
• For products using AC power source, power consumption shall be measured at aplug terminal for outlet.
• In the case of using AC power source, true power shall be referred to as power
consumption.
• For small routers having wireless function for LAN side interface, a packet
generator shall be used in the measurement.
(4) Display items and others
1) Display items shall be as follows.
• Product name or model name• Category name
• Frequency band and wireless output of a wireless connection interface (if a router isequipped with a wireless connection interface for LAN side)3• Transmission type of a wireless connection interface (if a router is equipped with awireless connection interface for LAN side)• Transmission frequency band which allows for the maximum effective transmission
rate (if a router is equipped with a wireless connection interface, whosetransmission frequency band is selectable, for LAN side).
• Energy consumption efficiency• Name of manufacturer2) Compliance items• A unit “GHz” shall be used for the frequency band of wireless connection interface,and “mW/MHz” for the wireless output.

The values shall be rounded off to one

decimal place and indicated as “2.4GHz band: [wireless output], 5GHz band:[wireless output]”.

The indication shall be omitted for the wireless frequency band

which is not supported by the product.
• Transmission type of a wireless connection interface shall be indicated as either
1-wave transmission, 2-wave selective transmission, or 2-wave simultaneoustransmission.
• Transmission frequency band which allows for the maximum effective transmission
rate shall be indicated as either 2.4GHz band or 5GHz band.
• Energy consumption efficiency shall be expressed in “W” and indicated as a value
rounded off to one decimal place.
• Display items shall be indicated in a durable manner at easily observable locations
on catalogues describing the product’s performance or on materials provided by the
manufacturer for product selection.
3. Proposal for energy saving(1) Actions of users
1) Efforts shall be made to select small routers with excellent energy consumption
efficiency and to reduce their energy consumption by appropriate and efficient
usage.
(2) Actions of manufacturers
1) Efforts shall be made to promote development of energy-saving technologies forsmall routers and to develop those with excellent energy consumption efficiency.
2) Aiming at the popularization of small routers with excellent energy consumption
efficiency, efforts shall be made to provide appropriate information so that users will
be able to select such small routers.

4(3) Actions of Government
1) Aiming at the popularization of small routers with excellent energy consumption
efficiency, efforts shall be made to take necessary measures, such as activities forpromulgation and enlightenment, so as to promote the efforts by users andmanufacturers.
2) Implementation of the display items by manufacturers shall be checked periodicallyand continuously.

Also, appropriate law management shall be made so that correctand easy-to-understand information regarding energy consumption efficiency will be
provided for users.
3) Energy efficiency standards based on the Top Runner method is a very effectivemeans to reduce energy consumption of products; therefore, efforts shall be made topromote better understanding about and to disseminate the Top Runner methodinternationally by catching appropriate opportunities.

5II. L2 switches
1. Target scope [See Attachment 1]
Box type L2 switches with 3 or more communication ports are covered.
Besides, L2 switches equipped with slots, all of which are supporting detachable
optical modules for photoelectric conversion, are regarded as box type.
2. Details of Evaluation Standards for Manufacturers(1) Target fiscal year [See Attachment 5]
Fiscal year 2011.
(2) Target standard values [See Attachment 6]
Concerning L2 switches to be shipped by a manufacturer to the domestic market in
the target fiscal year, for each category in the table below, the manufacturer has to makesure that the value obtained by weighting and averaging energy consumption efficiency
measured according to (3) with the number of shipped units shall not exceed the target
standard value.

Category

processing
With IP filteringA
B

IP address

Management function

With management

With SNMP

functionfunction

Without IP filteringfunctionCfunctionWith Web management and the likeStandard energy
consumption
efficiency{(αA⋅X + βA) + PA}/T{(αB⋅X + βB) + PB}/T{(αC⋅X + βC) + PC}/T

WithoutD{(αD⋅X + βD) + PD}/T

management
function

6

Table for αn values
Line speed

100M

1G

10G

Notation (αn)

α100M

α1G

α10G

Category A

0.578

1.880

15.900Category B

0.375

1.880

⎯

Category C

0.375

1.133

⎯

Category D

0.272

1.133

⎯

Power
consumption
coefficient(W/Port)

Table for βn values
Line speed

100M

1G

10G

100M+1G

1G+10G

Notation (βn)

β100M

β1G

β10G

β100M+1G1

β100M+1G2

β1G+10G

ValuesCategory A

3.976

9.940

0

2.276

0.576

−10.240(W)

Category B

3.400−5.070

⎯

1.700

0

⎯

Category C

3.400−2.074

⎯

2.447

1.494

⎯

Category D

0.824−2.074

⎯

1.494

1.494

⎯

If the power consumption (αn⋅X + βn) meets the following cases, the calculation
shall be made using the value specified.
1) If it is less than 3.000 at 100M and 100M+1G, the specified value shall be 3.000.
2) If it is less than 4.500 at 1G, the specified value shall be 4.500.

αn⋅X+βn Shortened form αn100MX100M + αn1GX1G + αn10GX10G + βn
Where, n represents category, αn(bps) represents a unit power consumption per(W) :port at each category and each line speed, X(bps) represents the number of ports
for each line speed, and βn represents a fixed power value for each category.
Example: αn ⋅X = αn100MX100M + αn1GX1G + αn10GX10G
T (bit/s) :Throughput measured

Pn (W) :Additional power consumption when taking the effect of PoE power supply into
account.
Where, n represents category (n: A, B, C, D).

Pn =0.0347⋅Pd / Ps
⋅ (αn⋅X + βn)1 − 0.0347⋅Pd / Ps
Ps = (αn⋅X + βn) ⋅ 0.850 + 1.000

7Pd (W) :PoE maximum supply power.

For units without PoE, it shall be Pd = 0.

Ps (W) :Secondary power of switch circuits and PoE control circuits.
Secondary power of switch circuits shall be calculated by applying
across-the-board 85% power supply efficiency to the basic formula for units
without PoE (αn⋅X+βn).
Secondary power of PoE control circuits shall be across-the-board 1W.

However, units whose PoE maximum supply power ratio (Pd/Ps) is within 16.000 are
only covered.
(3) Energy consumption efficiency measurement method [See Attachment 3]
Energy consumption efficiency shall be the value obtained by dividing power
consumption (W) measured according to the following method by the maximum
throughput (bit/s).

The power consumption shall be the value measured at a point

where the frame length (length of data blocks measured (frame)) is 1518 bytes using an
actual data communication.
{ Measurement configuration• It shall be a configuration so that the maximum throughput will be achieved at themeasurement packet length of 1518 bytes.
• The measurement shall be made after removing any parts and stopping any
functions within the scope of the switch’s maximum configuration, as long as they
are removable or stoppable without interrupting its basic performance/function.
• It is acceptable to conduct the measurement using a cascading connection
configuration for ports. In this case, the maximum throughput shall be calculated
taking the number of ports in the cascading connection into consideration.
• It shall be a configuration so that the unit under measurement will switch received
frames.
• Within the scope of the switch’s maximum configuration, ports not used in themeasurement are allowed to be link-down.
{ Measuring frame• Frames for unicast communication are used.
• Measurement frame length (PDU (Protocol Data Unit) length of Layer 2) shall be
1518 bytes.
• Header of each layer shall comply with IEEE802.3, IETF or other equivalent
standards.
• Data patterns of headers are discretional. Data patterns of measurement frames
shall be all 0.
• Bit rate (bit/s) and total number of frames sent to the unit under measurement
during the measurement are also allowed to be the required minimum to achieve themaximum performance.
{ Measurement conditions• Ambient temperature shall be between 16°C and 32°C.
• Supply voltage shall be the rated input voltage (100V or 200V) ±10% in the case of8

using AC power source. It shall be between DC−57V and DC−40.5V in the case ofusing DC power source.
• Frequency of AC power source shall be the rated frequency.
• Maximum throughput and power consumption shall be measured in while staying ina steady state.
• For products using AC power source, power consumption shall be measured at aplug terminal for outlet.
• In the case of using AC power source, true power shall be referred to as power
consumption.
(4) Display items and others
1) Items to be displayed are as follows.
• Product name or model name• Category name• Type and number of line ports• Maximum effective transmission rate
• Maximum power supplied by use of Power over Ethernet function (if a switch isequipped with it)• Energy consumption efficiency• Name of manufacturer2) Compliance items• As for the type and number of line ports, the type of either 100Mbit/s, 1Gbit/s or
10Gbit/s as well as corresponding number of ports in a configuration allowing forthe maximum throughput (effective transmission rate) shall be indicatedrespectively as follows: “100Mbit/s × [number of ports], 1Gbit/s × [number of ports],
and 10Gbit/s × [number of ports]”.
• The maximum effective transmission rate shall be expressed in “Gbit/s” andindicated as a value rounded off to one decimal place.
• The maximum power supplied by use of Power over Ethernet function shall be
expressed in “W” and indicated as a value rounded off to one decimal place.
• Energy consumption efficiency shall be expressed in “W/Gbit/s” and indicated as avalue rounded off to one decimal place.
• Display items shall be indicated in a durable manner at easily observable locations
on catalogues describing the product’s performance or on materials provided by the
manufacturer for product selection.
3. Proposal for energy saving(1) Actions of users
1) Efforts shall be made to select L2 switches with excellent energy consumption9efficiency and to reduce their energy consumption by appropriate and efficient
usage.
(2) Actions of manufacturers
1) Efforts shall be made to promote development of energy-saving technologies for L2
switches and to develop those with excellent energy consumption efficiency.
2) Aiming at the popularization of L2 switches with excellent energy consumption
efficiency, efforts shall be made to provide appropriate information so that users will
be able to select such L2 switches.
(3) Actions of Government
1) Aiming at the popularization of L2 switches with excellent energy consumption
efficiency, efforts shall be made to take necessary measures, such as activities forpromulgation and enlightenment, so as to promote the efforts by users andmanufacturers.
2) Implementation of the display items by manufacturers shall be checked periodicallyand continuously.

Also, appropriate law management shall be made so that correctand easy-to-understand information regarding energy consumption efficiency will be
provided for users.
3) Energy efficiency standards based on the Top Runner method is a very effectivemeans to reduce energy consumption of products; therefore, efforts shall be made topromote better understanding about and to disseminate the Top Runner methodinternationally by catching appropriate opportunities.

10

Attachment 1
Target Scope of Small Routers and L2 Switches
1. Scope of Routers and Switches to be covered
As well as being classified as communication devices according to “Japan standard
commodity classification”, targeted routers and switches are all of those intended mainly
to relay network data using the second layer (data link layer) or the third layer (network
layer) among models whose communication function is structured in layers based on OSI(Open System Interconnection) established by ISO (International Organization forStandardization).
However, the following products are excluded from the target scope, because themarket size and shipment volume are small and predicted to decrease from now on.

▪ Routers equipped with satellite interface(Shipment volume in FY 2004: approximately 800 units)▪ Routers with fixed ATM (asynchronous transfer mode) interface(Shipment volume in FY 2004: approximately 9,500 units)▪ Dial-up routers(Shipment volume in FY 2004: approximately 12,000 units)▪ L2 switches equipped with wireless(Shipment volume in FY 2006: approximately 28,000 units)
In addition, the following products are also excluded from the target scope, because
they fall into a group of models used for special applications, which are characterized byhaving more than half of ports not complying with IEEE802.3 standard, by depending on
power supplied from other products which the routers/switches are incorporated into, etc.

▪ HomePNA (Home Phoneline Networking Alliance) switches▪ DSLAM (Digital Subscriber Line Access Multiplexer) switches▪ Access point controlling switches▪ Routers/switches to be inserted into extension card slots, etc. of personal computers
and the like
Likewise, the following products are excluded from the target scope, because network
data relay functions are not considered as their primary functions, because test
procedures and evaluation methods for them have not been established, because they fall
into the group of early-stage products for which the standards are under development,
and so forth.

Necessary consideration, however, shall be given, when it is judged thatthese products should also be included in this target scope based on the changes inshipment volume in future or other information.

11▪ Set-top box (a generic name of products which are equipped with a device to extend
capabilities of TV sets, such as image delivery function to TV sets)▪ 802.11n products▪ PLC products
2. Scope of Small Routers and L2 Switches
Following small routers and L2 switches were reviewed.
(1) Small Routers
Targeted routers are all of those intended mainly to relay network data using the thirdlayer (network layer), among models whose communication function is structured inlayers based on OSI (Open System Interconnection) established by ISO (International
Organization for Standardization). To be specific, they are products which relay network
data referring to IP addresses.

Here, this relay operation means that a router counts

TTL of IP address header information backward and relays data to other data links.
Among routers defined in the above, small routers are those with effective
transmission rate of 200 Mbit/s or below (100 Mbit/s or below for wireless routers).
1) Definition of Target Small Routers
Some small routers are equipped with VPN function1 which is effective as asecurity function.

As for routers with a VoIP terminal having 3 or ports, although

they are multi-function terminals marketed differently from common routers for civil
demand as well as devices used as PBX (Private Branch eXchange), some of them also
fall in the scope of small routers.

If products have one or more of these 2 functions, it

is reasonable to review them together with large routers. Thus, they are excluded
from the definition of small routers to be covered.
Taking into consideration the above, target small routers is defined as follows.
Among small routers with effective transmission rate of 200 Mbit/s or below (100Mbit/s or below for wireless routers), models with the following characteristics aredefined as small routers to be covered.

▪ Not equipped with VPN function1; and▪ Having 2 or fewer lines in the case of being equipped with VoIP function.

1

VPN stands for Virtual Private Network. VPN function allows users to use public lines as if their own
private lines and utilizes tunnel techniques in order to avoid crosstalk. The tunnel techniques include
IPSec, PPTP, L2TP and SSL-VPN.

12

In addition, other small routers (which do not fit the above definition) shall be
examined around the same time as large routers which will continue to be deliberated
forward.
2) Definition of Effective Transmission Rate (throughput) of Small Routers
As shown in Figure 1-1, effective transmission rate (throughput) of routers is often
expressed differently for each product market; thus, there is no uniform way of
indication.

Here, an expression of effective transmission rate which is used for the

calculation of energy efficiency standard is defined as follows.
Effective transmission rate of small routers shall be expressed as follows.

▪ For those with other than wireless communication: sum of transmission
rates of download and upload.
▪ For those with wireless communication: transmission rate of download.
Category[1] Small routers(BB routers)[2] Small routers(Access routers)[3] Large routers

Expressions▪ 120 Mbit/s (70 Mbit/s for
wireless type)▪ 70 Mbit/s for download
and 50 Mbit/s for upload▪ 120 Mbit/s(Total sum of maximum
output capacity: 70 + 50
Mbit/s)▪ 240 Mbit/s(Total sum of input andoutput: 70 + 50 + 70 +50 Mbit/s)

RouterFigure 1-1 Input and Output Rates of Routers(2) L2 Switches
L2 switches shall be defined as box-type products with 3 or more communication ports
and intended mainly to relay network data using the second layer (data link layer), amongmodels whose communication function is structured in layers based on OSI (Open System
Interconnection) established by ISO (International Organization for Standardization).
To be specific, they are products which relay network data referring to MAC addresses.
Meanwhile, box-type L2 switches refer to those enclosed in a chassis which are capable ofrelaying data on a network through the second layer (data link layer) using a circuit

13

fixedly mounted onto the main body.

In addition, L2 switches equipped with slots, all ofwhich are supporting detachable optical modules for optical-electrical conversion, are also
considered as box-type.
1) Definition of Target L2 Switches
Chassis-type switches shall be discussed along with L3 switches rather than
within a scope of L2 switches, since they can also be reviewed within a scope of L3
switches. Thus, L2 switches to be reviewed here are limited to those of box-type.
2) Definition of Effective Transmission Rate (throughput) of Switches
Relaying capacity of switches is generally expressed as [1] switching performance
shown in Figure1-2, which is a sum of bits of input and output frames per second.
However, in the case of effective transmission rate (throughput), [2] expression using
throughput rather prevents measurers from misunderstanding.

In addition, a

uniformity of expression method with small routers can also be achieved with it.

Forthese reasons, the expression method is defined as follows for the calculation of energy
efficiency standards.
Effective transmission rate of L2 switches shall be expressed as follows.

▪ Number of output frames per second × total number of bits per frame.

Category
Expressions[1] Switching capacity[2] Throughput

400 Mbit/s
800 Mbit/s(Number of input frames + number Number of output frames × totalof output frames) × total number of number of bits per frame, at [1second]bits per frame, at [1 second]
In the case of 100 Mbit/s × 4 ports
100M （Upload, Input）
100M （Download, Output）
100M
100M
100M
100M
100M
100M
（bit/s）

Figure 1-2

Input and Output Rates of Switches

14

Attachment 2

Target Fiscal Year, etc. for Small Routers

1. Target fiscal year for small routers shall be fiscal year 2010 due to their short productrenewal cycle.
2. It is expected that improvement rate of energy consumption efficiency in the target
fiscal year will be approximately 16.3% based on assumption that there will be nochange in shipment volume and model composition of each category from the current
status (actual results of fiscal year 2006).
<Overview of Estimation>
1. Energy consumption efficiency estimated from values of actual achievements for smallrouters shipped in fiscal year 2006: 6.09W
2. Energy consumption efficiency estimated from the target standard values of smallrouters to be shipped in the target fiscal year (FY 2010): 5.10W
3. Improvement rate of energy consumption efficiency(6.09 − 5.10) × 100= 16.3%
6.09

15

Attachment 3

Categories for Target Setting and Target Standard Values for Small Routers
1. Categories for Target Setting(1) Basic concept
As for small routers covered in this review, following two factors greatly impact on
their power consumption.

Therefore, category setting shall be made based on thesefactors (See Figure 3-1).
• WAN side I/F (interface): Type of Ethernet, ADSL• LAN side I/F (interface): Type of Ethernet, VoIP (telephone), wireless
Ethernet: Registered trade mark of Fuji Xerox Co., Ltd.

(WAN side)Standard of LAN.

(LAN side)

Ethernet

CPU

ADSL

Ethernet

100M/10Mbit/s
Ethernet
SLIC / CODEC *1

VoIP (telephone)

MemoryWireless *2

Wireless*1 Routers with VoIP
*2 Routers with wireless

SLIC :

Subscriber Loop Interface Circuit
Interface circuit to connect telephones

CODEC:

Coder Decoder
Device which digitizes voice signals from telephones and transmits them to
WAN side as well as converts digital signals from WAN side to voice
signals.
Figure 3-1 Architecture of Small Routers(2) Specific category setting
1) WAN side I/F
There are two I/F types (Ethernet or ADSL) for small routers.

16

Transmission distance of Ethernet used for small routers is limited to maximum
100m.

Although currently there are 10Mbit/s, 100Mbit/s, 1Gbit/sps, etc. for Ethernet,

as far as small routers are concerned, I/F of 10Mbit/s and 100Mbit/s are taken into
consideration and collectively called Ethernet in this document.
Meanwhile, ADSL is a communication method connecting buildings oftelecommunications carriers with installation locations (such as houses) to transmit
data of some dozens of Mbps over long distance (maximum 6 to 7km). To cope with it,
the modulation-demodulation processing suitable for the long distance transmission isrealized by high-speed DSP (Digital Signal Processor), etc.

Compared to Ethernet,

ADSL requires more power because of this long distance transmission and theimplementation of modulation-demodulation processing.
Thus, from the viewpoint of power consumption, small routers are categorized by
the type of I/F for WAN side.
2) LAN side I/F
There are three main systems for LAN side, and they are used in several
combinations.
• Ethernet I/F
Equipped with Ethernet that is the standard interface, the routers can beconnected to ADSL, modems, optical network units (ONU), etc. and have highversatility. They can be constructed with fewer circuits than other two systems
described below. These routers are hereinafter called wired routers.
Meanwhile, as in the case of WAN side I/F, I/F of 10Mbits/s and 100Mbits/s arereferred to as Ethernet for small routers and collectively called Ethernet in thisdocument.
• VoIP (telephone) I/F
Equipped with VoIP function, wired routers can transmit voice signals as well as
data by means of being connected with telephones. Since SLIC and CODEC
functions to transmit voice signals (see Figure 3-1) are added, these wired routers
consume more power than ordinary wired routers do. For this reason, they need
to be categorized separately from the ordinary ones. Such routers with VoIP
functions are hereinafter called VoIP routers. As regards the telephone exchange
function, since it is contained in the CPU which executes routing processing that isa basic function of wired routers, it does not likely increase power consumption
meaningfully.
• Wireless I/FRouters which transmit data via wireless in addition to the wired router function.
Because of their easy connectivity and cheaper price, they are spreading widely inrecent years. The wireless system is currently standardized as IEEE802.11a, b, g.
Since MAC (Media Access Control) and RF (Radio Frequency) circuits are added inorder to transmit data by wireless, they consume more power than wired routers.
Thus, they need to be categorized separately from wired routers.

17Based on the consideration above, the basic categories are set as follows.
Table 3-1. Categories of Small Routers
LAN side I/F

Ethernet

With VoIPWith wireless

Wired routers

VoIP routers

Wireless routers(Category A)(Category B)(Category C)

ADSL routers withADSL routers with

VoIP

wireless(Category E)(Category F)

WAN side I/F
Ethernet

ADSL routers

ADSL(Category D)

2. Target Standard Values(1) Basic concept
Target standard values are set based on the idea of Top Runner method.

The specificpolicies are as follows.
(a) Target standard values shall be set for every category that has been appropriately
defined.
(b) As for the categories where future technological advances are expected to improve
efficiency, the target standard values shall allow for the improvement as much as
possible.
(c) Target standard values shall not conflict among categories.
(2) Room for improvement of energy consumption efficiency by future technology advances
Because of the following reasons, it seems appropriate not to include the room forenergy consumption efficiency improvement of small routers potentially achieved by
future technological advancement in the target standard values for now.
(a) In case of wired routers, the transmission rate of the WAN side network is fixed at
100Mbit/s and is not expected to be changed any time soon.

Addition of new

functions (i.e. addition of new ordinary communication functions except for VoIP or
wireless functions) are not anticipated either. Therefore, it is difficult to expect
further power saving from new technical innovation.
(b) In case of ADSL routers, the market is shifting to optical access (FTTH) and the net
decrease is observed in the number of subscribers (shrinking market) as shown in
Figure 3-2.

Taking the market shrink as the background factor, it is assumablethat new technologies have not been development since 2006.
difficult to anticipate the room for technical improvement.

18

Therefore, it is(Contracts: Unit: 10 thousand)(Contracts: Unit: 10 thousand)(Quarterly period)
1999

2000

2001

2002

2003

2004

2005

2006 (End of FY)

2004

2005

2006

(Year)

Cable internet
Wireless (FWA)
The numbers of contracts of FY2004 and afterward are those reported incompliance with the telecommunication business reporting rule, and thenumbers before that fiscal year are those arbitrarily reported by thetelecommunication companies.

The numbers of contracts of FY2004 and afterward are those reported incompliance with the telecommunication business reporting rule and thenumbers before that year are those arbitrarily reported by thetelecommunication companies.

Figure 3-2 Subscribers of ADSL Lines (FY2007 WHITE PAPER Information andCommunications in Japan)(3) Specific Target Standard Values
1) Wired routers: Category A
Power consumption (W)

電力
Power

16.00
14.00
12.00
10.00
電力
Power

8.00
6.00
4.00
2.00
0.00
0.00

50.00

100.00150.00200.00250.00

最大ｽﾙｰﾌﾟｯﾄ(Mbit/s)
Maximumthroughput (Mbit/s)

Figure 3-3 Measurement Result of Power Consumption of Wired Routers19

Figure 3-3 shows the measurement result of power consumption of wired routers.
It turns out to be that the power consumption values are distributed over a wide
range from 4W to 14W approximately.

It is assumed that some routers consume

large amount of energy because they are not strictly designed to save power in partfor the lack of energy-saving restriction or because a large variety of functions aremounted on them.

Based on the specification analysis, two routers having power

consumption of around 4W in the above figure are appeared to be wired routers withbasic functions only.

For this reason, 4W is taken as the Top Runner (hereinafter,

called TR) value.

202) VoIP routers: Category B
Power consumption (W)

VoIP

10
9
8
7
6
VoIP

5
4
3
2
1
0
0.00

50.00

100.00150.00200.00250.00Maximum throughput (Mbit/s)

Figure 3-4 Measurement Result of Power Consumption of VoIP Routers
Figure 3-4 shows the measurement result of power consumption of VoIP routers.
By collating and analyzing the measurement results and specifications, some values
were found to be the noise; thus, they were eliminated.

As a result, although thenumber of samples is limited, 5.5W is decided as the TR value.
3) Wireless routers: Category C
Wireless routers are those using wireless stipulated by the IEEE802.11 working
group for data transmission in addition to the wired router function. There are three
product groups based on the number of output radio waves.
• 1 wave transmission: Only one type of radio wave is available for transmission.
To be more specific, either 802. 11b, g or 802. 11a can be used.
•

2 wave switching transmission:

Although 2 types of radio waves are available

for transmission, only one type of them can be used at a time.
•

2 wave simultaneous transmission: 2 types of radio waves are available fortransmission and can be used simultaneously.
These product groups have different circuit compositions due to the differences in

specifications.

Typical circuit composition is shown in Figure 3-5.

21

RF 2.4G

MAC

CPU

1 wave transmission

2 wave switching transmission

RF 2.4G
MAC

CPU

RF 2.4G

MAC

CPU

RF 5G

MAC

RF 5G

2 wave simultaneous transmission

RF output part

Wireless MAC

Router basic function part

(Dependent on output)

part (Fixed value)(Fixed value)
RF: Radio Frequency
MAC: Media Access Control

Figure 3-5 Typical Circuit Element Composition of Wireless Routers

As shown in Figure 3-5, power consumption of wireless routers (P) can be
expressed as the sum of 3 circuit elements as follows.
P (Power Consumption)= RF part + Wireless MAC part + Router basic function parta) RF part
This circuit element sends/receives the wireless and realizes the physicallayer of the OSI (Open Systems Interconnection) reference model.

Its power

consumption depends on the wireless output power density (mW/MHz) and thefrequency band used (2.4GHz band or 5GHz band).

22b) Wireless MAC part
This circuit element is located between router basic function part and RF
part and realizes the function of MAC layer of the OSI reference model.

It shallbe a fixed value independently of wireless output power density and frequency
used.
c) Router basic function part
This circuit element provides the basic function which is common to both
wired and wireless routers and realizes the functions of LLC (Logical Link
Control) layer or above of the OSI reference model.

It is assumed that the 2wave simultaneous transmission requires more power than the 1 wave
transmission does because larger amount of data is processed at the former
transmission.
Based on the review above, the logical power of wireless routers can be expressed
as follows.
• 1 wave transmission
2.4GHz band is used.
P = (A2*X2) + B2 + C(a)5GHz band is used
P = (A5*X5) + B5 + C(b)• 2 wave switching transmission
Although either 2.4GHz band or 5GHz band can be used, it shall be thefrequency band that will provide the maximum throughput.
2.4GHz band is used.
P = (A2*X2) + B2 + C(a)5GHz band is used
P = (A5*X5) + B5 + C(b)• 2 wave simultaneous transmission
P = (A2*X2) + B2 + (A5*X5) + B5 + D(c)

Where, the symbols above represent the followings.
P: Power consumption
X2: 2.4GHz band wireless output (mW/MHz)
X5: 5GHz band wireless output (mW/MHz)

23

A2:
B2:
A5:
B5:
C:
D:

RF output coefficient for 2.4GHz band,
Wireless MAC power consumption for 2.4GHz band,RF output coefficient for 5GHz band,
Wireless MAC power consumption for 5GHz band,
Power consumption of router basic part,
Power consumption of router performance for 2 waves,

gradient
fixed value
gradient
fixed value
fixed value
fixed value

Following the study focused on the circuit composition, the measurement results ofwireless routers are analyzed (Figure 3-6 and Figure 3-7).

Although the number ofdata is not large, following features are found from the analysis.
a) The power consumption is positively related to the wireless output power density.
b) There is fixed power consumption which is not dependent on the wireless output
power density.
c) Wireless routers are grouped into 3 types, i.e. 1 wave transmission, 2 wave
switching transmission and 2 wave simultaneous transmission (Figure 3-7).
実測値
measurement values
無線ルータ（無線出力と消費電力）
Wireless routers (wirelessoutput and power consumption) Actual

Power consumption(W)
消費電力（W）

10

2.4GHz
１波

２波切り替え5GHz

987Calculated
計算値values
2 waveswitching transmission
２波切り替え送信6①◇2.4GHz②□5GHz5
4

1 wave１波送信
transmission

3
2
1
0
0

無線出力（mW/MHz）
10 Wirelessoutput (mW/MHz)

5

Figure 3-6 Measurement Result of Power Consumption based on Wireless Output PowerDensity (1 wave transmission, 2 wave switching transmission)

The measurement results of power consumption of both 1 wave transmission and 2
wave switching transmission wireless routers (Figure 3-6) were analyzed based on theconcept of logical power mentioned above.

24

As a result, each coefficient and each fixedvalue in the foregoing expressions (a) and (b) were calculated as follows.
A2 = 0.10, B2 + C = 3.9
A5 = 0.15, B5 + C = 3.9

2.4GHz band is used.
P = (0.10*X2) + 3.95GHz band is used.
P = (0.15*X5) + 3.9
10.0

Power consumption(W)
消費電力（W）

8.0

Top
Runner
トッ
プランナー

6.0

5.1
4.0
2.0
Wireless

0.0

0.0

5.0

10.0

15.0

output
無線出力20.0 (mW/MHz)(mW/MHz)

Figure 3-7 Measurement Result of Power Consumption based on Wireless Output PowerDensity (2 wave simultaneous transmission)

In the measurement result of power consumption of 2 wave simultaneoustransmission shown in Figure 3-7, the TR value is 6.0W.

According to thespecification of the product with this TR value, it is known that the product’stransmission power density for 2.4GHz band and 5GHz band is 3.5mW/MHz
respectively.

With the foregoing expression (c), moving (B2+B5+D) is to the left

and P to the right, then A2=0.10, A5=0.15, X2=3.5, X5=3.5 and P(TR)=6.0 are
entered.

As a result, 5.1W is obtained.

(B2+B5+D) = P − (A2*X2) − (A5*X5)= 6.0 − (0.10*3.5) − (0.15*3.5)= 5.1 W25

In the case of 2 wave simultaneous transmission
P = (0.10*X2) + (0.15*X5) + 5.1

4) ADSL routers
The measurement result of power consumption of ADSL routers (Figure 3-8) was
analyzed.

As a result, 7.4W was taken as the TR value, because there was no

meaningful difference between the power consumption values of ADSL routers
without VoIP (see ADSL without wireless in Figure 3-8) and ADSL routers with VoIP
(see ADSL without wireless & with VoIP in Figure 3-8).
routers with wireless was 8.8W.

The TR value for ADSL

Meanwhile, as a result of the product(specifications) analysis, it was assumed that the product with above TR value was nota special product.

小型ルーター（機能別）
Smallrouters (by function)Wrouters
区分Ｄ◇ ADSLADSLルーター
無線なしADSL（③）

Category D

14routers with VoIP
区分Ｅ ◆ ADSL
VoIP付ADSLルーター

Category E

無線なしVoIP＆ADSL付き（③）
ADSL routers with wireless
区分Ｆ △ 無線付ADSLルーター

Category F

12無線付きADSL（⑥）

10Ｆ ８．８W8

Ｄ，Ｅ ７．４W

6

4

2

0
0

20000

40000

60000

80000

100000120000140000160000180000200000Maximumthroughput (kbit/s)
最大ｽﾙｰﾌﾟｯﾄ(kbit/s)

Figure 3-8 Measurement Result of Power Consumption of ADSL Routers

26

Based on the study above and considering the background stated in 3. (2), the Top
Runner values for each category are indicated below as the target standard values.
Table 3-2
LAN side I/F
WAN side I/F

Target Standard Value of each Category

Ethernet

With
VoIP

With wirelessIn the case of 1 wave transmission or 2 wave
switching transmission:[2.4GHz band is used]

P = (0.10*X2) + 3.9[5GHz band is used]

P = (0.15*X5) + 3.9
Ethernet

4.0W

5.5W

In the case of 2 wave simultaneoustransmission:
P= (0.10*X2) + (0.15*X5) + 5.1
X2: 2.4GHz band wireless output power
density (mW/MHz)
X5: 5GHz band wireless output power density(mW/MHz)

ADSL

7.4W

7.4W

8.8W

As mentioned above, it became possible to express the target standard values for smallrouters in fixed values by taking 200Mbit/s as the upper limit of the transmission capacity.
As for routers with wireless, it is expressed by a linear expression having wireless output
power density as a variable, because there is positive correlation between wireless output
power density and power consumption.

27

Reference 4

Energy Consumption Efficiency of Small Routers and L2 Switches
and the Measurement Method

1.

Basic concept
Regarding routers and switches, instead of just trying to reduce absolute amountof energy they consume, the basic concept is an attempt to reduce their energy
consumption according to their relaying performance (throughput) which is a basic
performance indicator.
Meanwhile, energy consumption efficiency of routers and switches and themeasurement method are based on the result of study by “Technical Committee of
RoutersandSwitches”(Chairperson:

Itaru

Mimura)establishedunderCommunications and Information network Association of Japan.
The details are as described below.
2.

Specific details about energy consumption efficiency and measurement method(1) Energy consumption efficiency of small routers and the measurement method
The energy consumption efficiency shall be power consumption (W) measured by
the following method.
In general, a positive correlation will be found between power consumption andthe maximum throughput (see Figure 4-1), when making a study based on data shownin catalogues, etc.

Such correlation seems insignificant in the case of small routers;

therefore, power consumption (W) shall be taken as energy consumption efficiency.
In addition, since it was predicted that the power consumption would vary depending
on a length of measuring packet, measurements were carried out at 5 representative
points to see the difference.

As shown in Table 4-1, variation in these measured

power consumptions was not prominent; therefore, a single measurement point was
adopted.

Energy consumption efficiency shall be represented by the following expression.
E = P1500
E: Energy consumption efficiency (Unit: W)
P1500: Power consumption at measuring packet length of 1500 byte28

* For those, such as PPPoE-dedicated models, having a difficulty in being measured at
packet length of 1500 byte, the measurement may be conducted using data which
will result in the maximum packet length.
A)

Measurement configuration
1) It shall be configured so that it can achieve the maximum throughput at
measuring packet length of 1500 byte.

(Hereinafter, the configuration isreferred to as the router maximum configuration.)
The maximum throughput shall be a value defined by the following expression
and measured with the following configurations. The maximum upload output
packets and the maximum download output packets shall be counted
simultaneously. Power consumption shall be measured at the same time whenmeasuring the maximum throughput2. As for broadband routers with wireless
LAN interface, the measurement shall be made only for the wireless sending
direction (download: packets sending from WAN to wireless LAN), and power
consumption shall also be measured at the same time.
TX = (RX1 + RX2) × (X + Y) × 8
TX: Maximum throughput (Unit: bit/s)
RX1: Maximum number of upload output packets transferred per second bya unit-under-measurement
RX2: Maximum number of download output packets transferred per second
by a unit-under-measurement
X: Packet length (Unit: byte)
Y: Packet length for overhead3 (control information) (Unit: byte)
2) Any components which can be detached and any functions which can be turned
off without interfering basic performance and capability of routers shall be done
so within a scope of the router maximum configuration, when carrying out ameasurement.
3) A measurement may be carried out with ports connected according to a cascade
topology. When calculating the maximum throughput, the number of ports inthe cascading connection shall be taken into consideration.
4) It shall be set so that a unit-under-measurement will perform a routing forreceived packets.

For routers which are incapable of routing between specified

2

In order to decrease power consumption at the maximum load, it is necessary to make effort to reduce
power consumption of a product as a whole. With this effort, it is expected that power consumption
will decrease at loads close to those in the actual use.

3

In case that a line interface of a unit-under-test is Ethernet, the overhead shall be 38 byte (Interframe
Gap: 12 byte, Preamble: 8 byte, Ethernet Header: 14 byte, Frame Check Sequence: 4 byte).

29

ports (routers of asymmetrical configuration4), transferring packets via Layer 2
or Layer 1 is not considered as routing; therefore, such packets shall not be
included in the calculation of throughput.
5) Ports which are not used in a measurement within a scope of the routermaximum configuration are allowed to be link-down.
6) Wired broadband routers with wireless LAN interface shall be measured withthe following configuration.
a)Routers shall be configured so that the wireless sending direction (download
side: packets sent from WAN to wireless LAN) are only measured.
b) If routers are equipped with multiple wireless LAN interfaces which arecapable of simultaneous running, they shall be configured so that all theinterfaces run at the same time.
c) Data compression facilities and output power, etc. adjusting functions shallbe turned off.
d) Link rate shall be the maximum link rate of a unit-under-measurement.
B)

Measuring packets
1) IP packets for unicast communications shall be used.
2) Length of measuring packet (length of PDU (Protocol Data Unit) of Layer 3)
shall be 1500 byte.
3) Header of each layer shall comply with a certain standard, such as IEEE802.3
and IETF.
4) Data pattern of headers shall be discretional.

Data pattern of measuring

packets shall be all set to 0.
5) Bitrate(bit/s)

and

total

numberofpacketstransferredtoaunit-under-measurement in a measurement of power consumption may be theminimum of those needed to achieve the maximum performance.
C)

Measurement condition
1) Ambient temperature shall be in a range from 16 °C to 32 °C.

As for broadband

routers with wireless LAN function, the temperature span may be from 0 °C to
40 °C.
2) Supply voltage shall be in a rage of the rated input voltage (100V or 200V) ± 10%
in the case of AC power source.

The range shall be DC−57V to DC−40.5V for DC

power source.
3) Frequency of AC power source shall be a rated frequency.
4) Maximum throughput and power consumption shall be measured while staying
in a steady state.
5) For routers using AC power source, power consumption shall be measured at a4

See Figure 4-330

plug terminal for outlet.
6) In the case of using AC power source, true power shall be referred to as power
consumption.
7) For small routers having wireless function, a packet generator shall be used in
the measurement.

Table 4-1

Wired

Wireless

Power consumption
at each packet length

Calculated
power
consumption(W)

Product

Availabilityof wirelessfunction

Measurement Results of Power Consumption of Routers at each Packet
LengthTransmission
rate

Power
consumption
at link-up
(W)

46
byte

238
byte

494
byte

1006
byte

1500
byte

A

35.4 Mbit/s

8.40

8.53

8.51

8.50

8.50

8.53

8.52

B

38.7 Mbit/s

7.70

7.75

7.75

7.75

7.75

7.75

7.75

C

108 Mbit/s

5.40

5.32

5.33

5.34

5.37

5.32

5.33

D

1.75 Gbit/s

58.6

61.7

60.8

60.6

60.4

60.2

60.4

E

95.6 Gbit/s

370

482

427

409

401

398

403

F

382 Gbit/s

1328

1757

1539

1476

1445

1436

1456

G

17.9 Mbit/s

11.7

12.2

12.1

11.8

12.6

12.2

12.2

H

20.4 Mbit/s

3.96

3.95

4.09

4.05

4.22

4.21

4.18

I

21.2 Mbit/s

6.68

7.25

7.34

7.20

7.27

7.39

7.34

31

(2) Energy consumption efficiency of L2 switches and the measurement method
Energy consumption efficiency shall be a value obtained by dividing power
consumption (W) measured according to the following method by the maximum
throughput (bit/s).

The power consumption and maximum throughput shall bemeasured using an actual data communication with a frame length (length of a blockof data used for the measurement) of 1518 byte.
Reviewing data on catalogues, etc. and actual measurements, it was assumed
that the power consumption and the maximum throughput have a positive correlation(see Figure 4-2).

Therefore, “W/(bit/s)” was adopted as energy consumption efficiencyof L2 switches.
Also, as shown in Table 4-2, it was found that the power consumption hardly
depends on the frame length and stays almost constant. For this reason, a single
measurement point was adopted.
Energy consumption efficiency shall be a value obtained with the following
expression.
E = P1518 / T1518
Where, E, P1518, and T1518 represent the following value respectively.
E:

Energy consumption efficiency (Unit: W/(bit/s))

P1518:

Power consumption at measuring frame length of 1518 byte

T1518:

Maximum throughput at measuring frame length of 1518 byte

The maximum throughput shall be a value defined by the following expression andmeasured with the following configurations.

In order to obtain the maximum

throughput, the measurement shall be carried out using total number of output
frames of all ports, and they are performed simultaneously.

In addition, power

consumption shall be measured at the same time when measuring the maximum
throughput.
TX = RX × (X + Y) × 8
TX:

Maximum throughput (Unit: bit/s)

RX:

Summationofnumbersofframesoutputpersecondbyunit-under-measurement

5

X:

Frame length (Unit: byte)

Y:

Frame length for overhead5 (Unit: byte)

In case that a line interface of a unit-under-measurement is Ethernet, the overhead shall be 20 byte
(Interframe Gap: 12 byte, Preamble: 8 byte).

32

a

A)

Measurement configuration
1) It shall be a configuration so that the maximum throughput will be achieved at
the measurement packet length of 1518 bytes.

(Hereinafter, the configurationis referred to as the switch maximum configuration.)
2) The measurement shall be made after removing any parts and stopping any
functions within the scope of the switch’s maximum configuration, as long as
they

are

removableorstoppable

without

interrupting

its

basic

performance/function.
3) It is acceptable to conduct the measurement using a cascading connection
configuration for ports.

In this case, the maximum throughput shall becalculated taking the number of ports in the cascading connection into
consideration.
4) It shall be a configuration so that the unit under measurement will switch
received frames.
5) Within the scope of the switch maximum configuration, ports not used in themeasurement are allowed to be link-down.
B)

Measuring frames
1) Frames for unicast communication are used.
2) Measurement frame length (PDU (Protocol Data Unit) length of Layer 2) shallbe 1518 bytes.
3) Header of each layer shall comply with IEEE802.3, IETF or other equivalent
standards.
4) Data patterns of headers are discretional.

Data patterns of measurement

frames shall be all 0.
5) Bit rate (bit/s) and total number of frames sent to the unit under measurement
during the measurement are also allowed to be the required minimum to achieve
the maximum performance.
c)

Measurement condition
1) Ambient temperature shall be between 16°C and 32°C.
2) Supply voltage shall be the rated input voltage (100V or 200V) ±10% in the caseof using AC power source.

It shall be between DC−57V and DC−40.5V in thecase of using DC power source.
3) Frequency of AC power source shall be the rated frequency.
4) Maximum throughput and power consumption shall be measured in whilestaying in a steady state.
5) For products using AC power source, power consumption shall be measured at aplug terminal for outlet.
6) In the case of using AC power source, true power shall be referred to as power
consumption.

33

Table 4-2

Measurement Results of Power Consumption of L2 Switches based on Frame
Length (Examples)Power consumption efficiency based on frame length(W)

Switching
Capability(Gbit/s)Powerconsumption
at link-up(W)

64 byte

256 byte

512 byte

1024 byte

1518 byte

Calculated
power
Consumption
(W)

A

0.5

3.2

3.2

3.2

3.0

3.2

3.2

3.2

B

1.6

6.0

6.2

6.1

6.1

6.2

6.2

6.2

C

6.4

112.0

114.0

113.0

112.0

113.0

112.0

112.3

D

0.9

16.3

16.4

16.4

16.4

16.4

16.4

16.4

E

0.8

3.9

3.9

3.9

3.9

3.9

3.9

3.9

F

48.0

41.0

41.0

41.0

41.0

41.0

41.0

41.0

Ｇ

8.8

33.7

34.7

34.7

34.7

33.7

33.7

33.8

Ｈ

1.8

92.0

92.0

92.0

92.0

92.0

92.0

92.0

Product

ルーター
Routers
消費電力(W)
Power
Consumption (W)100000

10000

1000

100

10

1
0.1

1

10

100

1000

10000

1000001000000 10000000

最大スループット(Mbit/s)
Maximum
Throughput (Mbit/s)

Figure 4-1 Correlation between Power Consumption and Maximum Throughput(Routers)

34

スイッチ
SwitchesPower
Consumption (W)
消費電力(W)
100000

10000

1000

100

10

1
0.1

1

10

100

1000

10000

1000001000000 10000000

最大スループット(Mbit/s)
Maximum
Throughput (Mbit/s)

Figure 4-2 Correlation between Power Consumption and Maximum Throughput(Switches)

Routers of Asymmetrical
Configuration

Hub ports
Link down

WAN port
RouterHubfunctionfunction

Link down
Link down

Packet flow
Figure 4-3 Routers of Asymmetrical Configuration*Routers of asymmetrical configuration:
Routers which are incapable of routing between specified ports.
The maximum performance of them is achieved with WAN port and one of hub ports.

35

Attachment 5

Target Fiscal Year, etc. of L2 Switches

1. In the power consumption of L2 switches, the power consumed by dedicated LSI (ASIC:
Application Specific IC) for L2 switches and memories is dominant.

Thus, to achieve

the target, new development of components, such as ASIC for L2 switches, is necessary.
However, including the development of ASIC, it takes at least 2 to 3 years from theplanning phase up to the delivery to develop L2 switches. Also, users need at least 3
years to change/replace old models with new ones.

Therefore, the target fiscal year forL2 switches shall be set as fiscal year 2011.
2. In addition, the improvement rate of energy consumption efficiency in the target fiscal
year is expected to be approximately 37.7% based on the assumption that there will be
no change from the current status (actual result in FY 2006) regarding the shipment
volume and the composition of each category.
<Overview of Estimation>(1) Energy consumption efficiency estimated from values of actual achievements of L2
switches shipped in fiscal year 2006:

6.36 W/Gbit/s(2) Energy consumption efficiency estimated from the target standard values for L2
switches to be shipped in the target fiscal year (FY2011):(3) Improvement rate of energy consumption efficiency(6.36 − 3.96) × 100= 37.7%6.36

36

3.96 W/Gbit/s

Attachment 6

Categories for Target Setting and Target Standard Values of L2 Switches
1. Categories for Target Setting(1) Basic concept
Main factors giving impact to the power consumption of L2 switches are type ofcommunication lines (specifically, line speed of 10Gbit/s, 1Gbit/s, 100Mbit/s) and thenumber of equipped communication lines (referred to as the number of ports) (seeFigure 6-1).

The management function realized by using additional electronic

circuits (such as CPU), the availability of IP address processing (such as filtering), andthe availability of PoE (Power over Ethernet) function which started to spread
recently have also significant impact to the power consumption of L2 switches (seeFigure 6-2 and Figure 6-5).

In the light of the above, categories for L2 switches shallbe set based on above described factors.
Ethernet: Registered trade mark of Fuji Xerox Co., Ltd. Standard of LAN.

70

Power消費電力(W)consumption (W)60
y = 15.9x50
y = 1.8237x + 1.4116

30

10Ｇbps 管理あり
1Ｇbps
管理あり
1Gbps
with management
1Gbps
withoutmanagement
1Ｇbps
管理なし
100Mbpswith management
100Mbps
管理あり
100Mbpswithout管理なし
management
100Mbps
10Gbps with management40
y = 1.1112x - 1.2903

20
y = 0.3898x + 3.603
10
y = 0.2771x + 2.0468
0
0

8

16

24

Numberof ports
ポート数

Figure 6-1 Comparison by Communication Line Speed and Presence of Management
Function37

70Power消費電力(W)consumption (W)60
y = 7.5121x + 4.1176
50

PoEあり
With
PoE

（測定はPoE負荷なし）(Measurement
is made40

without PoE load)Without
PoE (TR value at the
PoEなし

30

same
throughput and in the（同スループット、同区
same
category)
分におけるTR値

y = 3.1647x + 2.006
20
10
0
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

スループット(Gbps)
Throughput(Gbps)

Figure 6-2 Comparison of switches with and without PoE function(2) Specific category setting1) Line speed and the number of ports
As for L2 switches, variety of combinations of line speed and the number of ports
are available depending on the usage within networks, the number of connected
terminals and the communication band (see Figures 6-3 & 6-4).

There are products

the line speed and the number of ports of which are different even if their throughput
is the same.

For example, with respect to the products with 44 Gbit/s, some may

have 2 ports of 10Gbit/s line and 24 ports of 1Gbit/s line, and others may only have 44
ports of 1Gbit/s line.

Besides, the range of throughput is wide (tens Mbit/s to tens

Gbit/s), and the number of ports ranges from 3 ports to 48 ports or more.

It is notpractical to handle all the combinations as different categories, because it makes thecategories complicated and the number of products to be covered in each category
becomes fewer.

Therefore, for such products having various combinations of line

speed and ports, power consumption standard values shall be determined by use of
relational expressions with the communication line speed and the number of ports as
variables, instead of categorical approach.

10G line port

Figure 6-3 Example of L2 switch (1G × 48 ports + 10G × 2)

38

1G line port

Figure 6-4 Example of L2 switch (1G × 24 ports)
2) Management function
With respect to L2 switches, the availability of management function (SNMP(Simple Network Management Protocol) function, Web management function, etc.) isdifficult to be expressed in a relational expression using physical amount; therefore, it
is appropriate to handle it by separating categories.

As shown in Figure 6-5, actual

measurement reveals that the power consumption characteristics will vary dependingon the availability and the type of management function.

In this Figure, thecomparison is made with a single line speed of 1Gbit/s to illustrate the power
characteristics based on the difference in management function.

From the figure, it

is observed that L2 switches supporting SNMP which is an enhanced management
function consume large amount of power, that those supporting Web which is arelatively simplified function consume less power, and that those without any
management function consume much less power.
3) IP filtering function
Likewise, with respect to L2 switches, the IP address processing function isdifficult to be expressed in a relational expression using physical amount; therefore, it
is appropriate to handle it by separating categories.

The IP filtering function is

included in the IP address processing function.

It is the function to filter

communication packets at IP level referring to IP address of sender/receiver, protocol,
ports, etc. in order to enhance security and to allow flexible network design.
equipped to recent high-function L2 switches.

It is

As shown in Figure 6-5, the power

consumption clearly differs according to the availability of IP filter function (seeCategory A and Category B).

39

120
100
Power consumption
消費電力(W) (W)y = 1.8613x + 11.55
80
区分A：SNMP+IPFﾞ
区分B：SNMP
Category
C: Web, etc.
区分C：Web等
Category
D: Without management
区分D：管理なし
Category A: SNMP+IPF
Category B: SNMP60
y = 1.8237x + 1.4113

40

y = 0.7575x + 6.2867
20

y = 1.1112x - 1.2903

0
0.0

10.0

20.0

30.0

40.0

50.0

60.0

スループット(Gbps)
Throughput(Gbps)

IPF: IP filtering
Figure 6-5 Categorical Comparison in the case of with 1Gbit/s and without PoE(Management Function)4) PoEThe power consumption of L2 switches differs depending on the availability of PoE
function even though they have the same number of ports.

In other words, theproducts supporting PoE is consequently equipped with large capacity of power supply
to supply power through ports; therefore, power supplied through ports and power
steadily consumed by the power supply exist within them. As a result of the study, it
is found that a relational expression using the maximum supply power (rated) of PoE
as a variable is possible (as for details, see the appendix).

Thus, the target standard

value for L2 switches supporting PoE shall be determined by use of the relational
expression, instead of categorical approach.
From the above, L2 switches are first classified by the availability of management
function.

Then, those equipped with management function are further divided into agroup of those having SNMP function and a group of those having Web management
function and the like.

For those with SNMP function, the availability of IP filteringfunction is taken into consideration for the further grouping.

Consequently, the basic

categories of L2 switches shall be set as 4 categories as shown in Table 6-1.

40

Table 6-1

Categories of L2 switches

Management function
Withmanagement
functionWith SNMP function

IP address processing

Category

With IP filtering function

A

Without IP filtering function

B

With Web management
and the likeC

Withoutmanagement
functionD* IP filtering function is a function that blocks the transmission of frames of specific IP
addresses referring to the IP addresses.
2. Target Standard Values(1) Basic concept
Target standard values are set based on the idea of Top Runner method.

The

specific policies are as follows.
(a) Target standard values shall be set for every category that has been appropriately
defined.
(b) As for the categories where future technological advances are expected to improve
efficiency, the target standard values shall allow for the improvement as much as
possible.
(c) Target standard values shall not conflict among categories.

(2) Room for improvement of energy consumption efficiency by future technology
advances
Because of the following reasons, it seems appropriate not to include the room forenergy consumption efficiency improvement of L2 switches potentially achieved by
future technological advancement in the target standard values for now.
1) Target standard values are determined by using the relational expression
described in paragraph (3) below.

When deriving the relational expression, since

it is a linear approximation, the coefficient is obtained by using the values of two
products having the number of ports associated with excellent energy efficiency(Top Runner values) as representing values.

Consequently, for L2 switches

having different number of ports except for those with the representing values,
energy consumption efficiency target standard values are higher than the current
Top Runner values (of the product group).
2) Especially in case of switches supporting 100Mbit/s to 1Gbit/s, it is difficult to
expect further energy saving by new technological innovation, because new41

functions are not anticipated to be added, because the chips used in the products
have sufficiently achieved the performance target with current semi-conductor
technologies, and etc.
(3) Specific target standard values
As mentioned in 1-(2) above, basic categories are those 4 categories.

To deal withthe variability of line speeds, the target standard values shall be determined byrelational expressions. The concept is described below.
1) Standard power consumption based on line speed and number of ports
According to the conventional studies, it was known that power consumption of aL2 switch having ports of single line speed only is the sum of power constantly
required by products (power consumed by power supply and basic circuits) andincreasing power as the number of ports increases.

In other words, the power

consumption approximately proportionate to the number of ports equipped.

Being

supported by the graph (power consumption vs. number of ports/throughput) plotting
Top Runner values of products with different number of ports, this interpretation isassumed to be correct. The power consumption is fundamentally expressed by theexpression (1) below.
Power consumption P = α line speed ⋅ X line speed + β line speed … Expression (1)Where,

α line speed is unit power consumption per port at ports of that line speed (coefficient).
β line speed is power constantly consumed by product of that line speed (fixed value).
X line speed is the number of ports of that line speed.
As a result of analyzing the measurement data, it was found that α varies
depending on the line speed.

To be more specific, the relationship is α100M < α1G <

α10G, showing that the power consumption per port (coefficient) increases as the line
speed becomes faster.
2) Extension in case of products supporting multiple lines speeds
As mentioned above, some L2 switches are equipped with various ports of multiple
line speeds (hereinafter, called port-mix).

Products which are equipped with a few

high-speed lines for the network core (center side) and many lines of relatively low
speed at the terminal side are currently available in the market.

In this paragraph,extension of the relational expression is operated so as to represent such port-mix
products. Basic idea of this extension is to total the relational expressions for every
port.
PMIX = (α100M ⋅ X100M + β100M) + (α1G ⋅ X1G + β1G) + (α10G ⋅ X10G + β10G)42

= (α100M ⋅ X100M + α1G ⋅ X1G +α10G ⋅ X10G) + (β100M + β1G + β10G) …Expression (2)As for the term (β100M + β1G + β10G) expressing the power constantly consumed, it
will not be the simple sum in the case of port-mix products, because the circuits can bepartially shared.
each category.

In light of the above, βn is obtained from the values measured forBased on this idea, the relational expression becomes the expression(3) as below.
= (α100M ⋅ X100M + α1G ⋅ X1G + α10G ⋅ X10G) + β… Expression (3)In this connection, αn is known to be different in each category based on theanalysis.

In other words, for those which perform highly-functional processing suchas IP filtering, they consume power differently at each type of port.

This isreasonable because the capacities of circuits, memories and etc. increases to realize
the required function.
Based on these ideas, the coefficient α is set for each category.

The coefficients ofpower consumption per port obtained from measured Top Runner values are as per
Table 6-2, and they are adopted as the coefficients of the expression (2).
Table 6-2

List of coefficient α

Line speed

100M

1G

10G

Notation (αn)

α100M

α1G

α10G

Category A

0.578

1.880

15.900Category B

0.375

1.880

⎯

Category C

0.375

1.133

⎯

Category D

0.272

1.133

⎯

Power
consumption
coefficient(W/Port)*) Currently Category B, C, and D for 10G are not available; therefore, their coefficientsare not set this time.

As mentioned above, coefficient βn is not the simple sum of the fixed value βn ofevery line speed and varies depending on the combination of line speed (port).

Thus,

the coefficient βn is determined for each combination of line speed based on themeasurement data.
In the measurements of products having both 100Mbit/s and 1Gbit/s ports, reverseare cases in which 1) energy consumption of products with 100Mbit/s port only and 2)
energy consumption of products with 100Mbits/s + 1Gbits/s × 2 ports are reversed [1)>2)].

Meanwhile, when comparing with 3) products having 100Mbit/s + 1Gbit/s × 1

port, there are some cases in which no difference in the unit power corresponding to
1Gbit/s port [2)≈3)].

Therefore, a combination of 100Mbit/s + 1Gbit/s × 1 port isestablished for β to make 100Mbit/s < 100Mbit/s + 1Gbit/s × 1 < 100Mbit/s + 1Gbit/s ×2.

In this connection, 1Gbit/s × 1 port is expressed as β100M + 1G1 and 1Gbit/s × 2 ports

or more is expressed as β100M + 1G2.

43

Each coefficient (βn) obtained from Top Runner values in the measurements is as
per Table 6-3 below.6
List of Coefficients β

Table 6-3
Line speed

100M

1G

10G

100M+1G

1G+10G

Notation (βn)

β100M

β1G

β10G

β100M+1G1

β100M+1G2

β1G+10G

ValuesCategory A

3.976

9.940

0

2.276

0.576

−10.240(W)

Category B

3.400−5.070

⎯

1.700

0

⎯

Category C

3.400−2.074

⎯

2.447

1.494

⎯

Category D

0.824−2.074

⎯

1.494

1.494

⎯

*) Although a combination of 100Mbit/s line + 100Gbit/s line is possible, it is notincluded here because there is no such product with the combination. In addition,coefficients for Category B, C and D of 10Gbit/s are not provided here due to thelack of existing products falling into these categories.
3) Target standard values for products with fewer ports
As for small L2 switches, the same as in the case of small routers, there is an area
in which the correlation between the performance (throughput/number of ports) andthe power consumption deviates from the foregoing relational expression (linear
approximation). This is probably the case where the constant power consumption isgreater than the power consumed by communication lines and also where the power
proportionate to the number of ports is extremely lower than the constant power
consumption.

Specifically, in the case of L2 switches with less than 8 ports, thestandard value obtained by the expression (3) and the current Top Runner value aredifferent. For these products with less than 8 ports, the current Top Runner value
shall be set as the target standard.
To be more specific, the standard values are set as follows for products of 1Gbit/s ×
5 ports or less in Category D and products of 100Mbit/s × 8 ports or less in Category
D.7a) For products of 100Mbit/s × 8 ports or fewer in Category D, target standard
value shall be 3.0W.
b) For products of 1Gbit/s × 5 ports or fewer in Category D, target standard value
shall be 4.5W.
As for the products currently not existing, if, as a result of calculation using the6

In Table 6-3, there is a field in which βn(y intercept) becomes a minus value. βn is the constant
power consumption when the number of ports is 0; therefore, it shall be reasonably a plus value. In
fact, when the number of ports is 3 or more (box switch of this time), it is always a plus value. This
reverse phenomenon is probably due to the rationalization effect made to the circuits by port-mix.

7

In theory, products of 100Mbit/s × 5 ports should be the ones with minimum value. However,
because Top Runner value of 8 port products is slightly smaller, the target standard value for themis set as the standard value (fixed).

44

relational expression, the value becomes smaller than above 2 values, these 2 values
are applied.

For port mix products, the value of those the line speed of which isslower is applied.

The relevant products are specifically described below.

c) For products with 1G × 5 ports or fewer in Category B and Category C, thetarget standard value shall be 4.5W.
120

消費電力(W) (W)Power consumption

100

区分A：1G+10G基準値
Category
A: 1G standard value
区分A：1G基準値
区分B：1G基準値
Category
B: 1G standard value
区分C：1G基準値
Category
C: 1G standard value
区分D：1G基準値
Category
D: 1G standard value
区分A：1G+10G
Category A: 1G + 10G
区分A：1G
Category
A: 1G
Category
B: 1G
区分B：1G
Category
C: 1G
区分C：1G
CategoryD:1G
区分D：1G
Category A: 1G + 10G standard value

80
60
40
20
4.5
0

※区分Cは区分Dと同じ

0.0

20.0

40.0

60.0

80.0

スループット(Gbps)
Throughput (Gbps)* Category C is the same as
Category D.

Figure 6-6 Power Consumption Target Standard Value, 1G and 1G + 10G, without PoE

25

20
区分A：100M基準値ﾞ
区分B：100M基準値ﾞ
Category
C: 100M standard value
区分C：100M基準値ﾞ
Category
D: 100M standard value
区分D：100M基準値ﾞ
Category
A: 100M
区分A：100Mﾞ
Category
B: 100M
区分B：100M
Category
C: 100M
区分C：100M
Category
D: 100M
区分D：100M

Power consumption(W)
消費電力(W)

Category A: 100M standard value

Category B: 100M standard value

15

10

5

* Category
C is the same as※区分Cは区分Bと同じ
Category B.

3

0
0.0

1.0

2.0

3.0

4.0

5.0

6.0

スループット(Gbps)
Throughput (Gbps)
Figure 6-7 Power Consumption Standard Value, 100M without PoE

454) Concept of PoE standard value (See the attachment for details)
PoE supporting products combine switching function and power supply function.
It can be paraphrased that “a product with PoE is one without PoE plus PoE function”
or “a product without PoE is one with PoE the power supply capacity of which is zero”.
The standard value shall be determined using a relational expression in a way thatsatisfies this correlation.

To do this, a correction term (corresponding to the powerincreased by PoE) is added to the relational expression (3).

Concept of the correction

terms are described in the attachment in detail, and it is briefly described here.

As aresult of reviewing, it was found that these correction terms could turn the maximum
supply power of PoE (Pd) and the power consumption of L2 switch circuit (Ps) into
parameters.

Thus, they are determined by using Top Runner values of current PoE

products so that the method resulting in the best power consumption efficiency would
be selected when installing the PoE function.
Meanwhile, as regards mainstream models, the ratio of maximum supply power
capacity to power consumption of L2 switch circuit (the maximum supply power ratio)
is within 16 times. In addition, models with the ratio exceeding 16 times are rare,
and the shipment volume is small. Therefore, the products with the ratio of up to 16
times shall be targeted here.

46

Based on the study results above, the Top Runner values for each category aresummarized as follows.
Table 6-4

Categories and standard values for L2 switches
IP address

Management function
With
With
management
function

SNMPfunctionStandard energy consumption

Category

processing

efficiency

With IP filteringfunctionA{(αA⋅X + βA) + PA}/T

Without IP
filtering function

B{(αB⋅X + βB) + PB}/T

C{(αC ⋅ X + βC) + PC}/T

D{(αD ⋅ X + βD) + PD}/T

With Web management andthe like

Withoutmanagement
function
Table for αn values
Line speed

100M

1G

10G

Notation (αn)

α100M

α1G

α10G

Category A

0.578

1.880

15.900Category B

0.375

1.880

⎯

Category C

0.375

1.133

⎯

Category D

0.272

1.133

⎯

Power
consumption
coefficient(W/Port)

Table for βn values
Line speed

100M

1G

10G

100M+1G

1G+10G

Notation (βn)

β100M

β1G

β10G

β100M+1G1

β100M+1G2

β1G+10G

Value

Category A

3.976

9.940

0

2.276

0.576

−10.240(W)

Category B

3.400−5.070

⎯

1.700

0

⎯

Category C

3.400−2.074

⎯

2.447

1.494

⎯

Category D

0.824−2.074

⎯

1.494

1.494

⎯

If the power consumption (αn⋅X + βn) meets the following cases, the calculation shallbe made using the value specified.
1) If it is less than 3.000 at 100Mbit/s and at 100Mbit/s + 1Gbit/s, thespecified value shall be 3.000.
2) If it is less than 4.500 at 1Gbit/s, the specified value shall be 4.500.

47

αn ⋅ X+βn (Watt) :Shortened form of αn100MX100M + αn1GX1G + αn10GX10G + βn
Where, n represents category, αn(bps) represents a unit power
consumption per port at each category and each line speed, X(bps)represents the number of ports for each line speed, and βn
represents a fixed power value for each category.
Example: αn ⋅X = αn100MX100M + αn1GX1G + αn10GX10G

T (bps) :Throughput measured.

Pn (Watt) :Additional power consumption when taking the effect of PoE
power supply into account.
Where, n expresses the category (n: A, B, C, D)

Pn =0.0347 ⋅ Pd/Ps⋅ (αn ⋅ X + βn)1 − 0.0347 ⋅ Pd/Ps
Ps = (αn ⋅ X + βn) ⋅ 0.850 + 1.000

Pd (Watt) :PoE maximum supply power.

In the case of units without

PoE, it shall be Pd = 0
Ps (Watt) :Secondary power of switch circuits and PoE control circuits.
Secondary power of switch circuits shall be calculated byapplying across-the-board 85% power supply efficiency to thebasic formula for units without PoE (αn⋅X+βn).
Secondary

power

of

PoE

control

circuits

shall

be

across-the-board 1W.
However, units whose PoE maximum supply power ratio (Pd/Ps) is within
16.000 are only covered.

48

Appendix: Concept of Standard Value for Products with PoE Power Supply Function(Detail)
1. Basic concept
PoE (Power over Ethernet) function is a function which supplies power to opposing
products through communication cables made of metal. As VoIP terminals, wirelessaccess points, etc. becoming popular in recent years, PoE also started to spread as afunction to supply power to such devices.
PoE is a complex product of power supply function and L2 switch function, and the
majority of current products are in a form where PoE function is added to L2 switch thatis a base of the product. Therefore, it is desirable to determine the standard value using
the same relational expression which can comprehensively cover products with andwithout PoE.
Thus, as a basic concept, a relational expression correcting power according to thepower supply capacity of PoE is developed for the products without PoE function based on
the relational expression for products with PoE function. The standard values shall becalculated using the obtained expression.
Based on the concept above, the expression f is introduced which relates the power
consumption standard value for products with PoE function to the standard value of
products without PoE function. It can be developed using the maximum supply power ofPoE (Pd) and expressed as follows.
Standard value P for products without PoE= f (Pd) ⋅ Standard value PPoE for products with PoE······ A1

It is more understandable to see that the standard value for products with PoE
function is made of the standard value of products without PoE function withincremental power according to the additional function. Therefore, the expression A1
is transformed to the expression A2 below. The concept is that a correction forincrement by PoE is made to the standard value for products without PoE. (SeeAdditional Explanation: Concept of the Relational Expression.)Standard value PPoE for products with PoE= Standard value P for products without PoE /f (Pd)= (αn ⋅ X + βn) / f(Pd)······· A2
The relational expression f(Pd) is determined from the plot diagram of measurement
results of products with PoE (Figure 6-8) and defined as follows.
f (Pd) = 1 – γn ⋅ Pd/Ps
Pd :PoE maximum supply powerPs :Secondary power of switching circuit and PoE control circuit

γn :Correction coefficient for PoE maximum supply power ratio (Pd/Ps)

Pd/Ps is the maximum supply power ratio showing the multiplying factor of PoE’s
maximum supply power to the secondary power of switch circuit (including PoE control
circuit). The current measurement of PoE is conducted according to the method without
setting load (terminals, etc.) for PoE. With this method, as the PoE’s maximum supply

49

power ratio increases, the load factor of power supply decreases, resulting themeasurement to be made at the point where the conversion efficiency of power supply is
low. This is corrected by the relational expression f(Pd).
Based on the above, the standard power of PoE is expressed as follows.
PPoE = (αn ⋅ X + βn) / (1 – γn ⋅ Pd/Ps).........A3

The expression A3 can be transformed as follows.
PPoE = (αn ⋅ X + βn) +γn ⋅ Pd/Ps⋅ (αn ⋅ X + βn)1 − γn ⋅ Pd/Ps........ A4

Pn can be expressed as follows. (See Additional Explanation for the detail of thistransformation)Pn =γn ⋅ Pd/Ps⋅ (αn ⋅ X + βn)1 − γn ⋅ Pd/Ps.........A5

Since Pd (maximum supply power) = 0 in the expression A5 for products without PoE
function, additional portion Pn = 0.

Thus, both products with PoE and without PoE canbe expressed by one relational expression.
As power for each category is included in the secondary power Ps of switch circuit, γn
is commonly defined for all categories and fixed as follows based on actual measurement.

γn = 0.0347
Secondary power Ps of switch circuit (including PoE control circuit) is expressed asfollows.
Ps = Switch circuit’s secondary power + PoE control circuit’s secondary power
Secondary power of switch circuit is determined by introducing 85% power supply
efficiency (Figure 6-9) in the standard expression for products without PoE and can be
expressed as follows.
Switch circuit secondary power = (αn ⋅ X + βn) ⋅ 0.85
Meanwhile, secondary power of PoE control circuit is defined as 1.00W based on
actual measurement.
(1) Concept of addressing products with PoE supply power
As for PoE extra incrementation, it is necessary to increase the extra correction rate
(inverse number of f(Pd)).

It is because the larger the capacity of maximum supply

power, which is calculated with Pd/Ps (maximum supply power ratio) expressing how
many times it is larger than the power consumed by switch circuit, etc., the more thepower supply load; moreover, the low power supply efficiency is used in the current

50

measurement method where PoE load is not applied.
In Figure 6-8, it is judged for f(Pd) that a primary approximation is possible from thetypical examples of the power supply efficiency curve against the power supply’s loadrate shown in Figure 6-9.

The inclination of the straight line is obtained from the Top

Runner values in the measurement result of products with PoE.

1
0.9
0.8
y = -0.0347x + 1

0.7

PoEあり全体
基準値
Actualmeasurement
実測分
TR
ＴＲ

f(Pd)

0.6

Overall with PoEStandard value

0.5
0.4
0.3
0.2
0.1
0
0

5

10

15

20

25

30

最大供給電力率
Pd/Psrate Pd/Ps
Maximum
supply power
Figure 6-8 Measurement Result for Correction Coefficient γn (inclination) obtained from
the Maximum Supply Power Rate using Primary Approximation

51

90.0%
80.0%
Power supply
efficiency (%)
電源効率(%)

70.0%
60.0%
50.0%

Power supply
電源効率曲線
efficiency curve

40.0%
30.0%
20.0%
10.0%
0.0%
0.0%

20.0%

40.0%

60.0%

80.0%

100.0%

電源負荷率
Power
supply load rate
Figure 6-9 Typical Examples of Power Supply Efficiency Curve

70
24+2G

60

消費電力(W)
Power consumption
(W)

50
Data
データ
Standard value
PoEなし基準値
without
PoE

対
象

40

外

給電370W
Supplypower 370W
Supplypower 300W
給電300W30

Supplypower 170W
給電170W

20
10
0
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

スループット(Gbps)
Throughput(Gbps)

Figure 6-10

Standard Values for Products with PoE and Area of Outside the Scope52

2. Supplementary explanation on target scope of PoE productsReviewing the actual measurement of L2 switches, it is found that currently the
majorities of products are those whose ratio of the maximum supply power capacity
against the power consumption of L2 switch circuit is 16 or lower as shown in Figure 6-8.
There are some PoE products plotted in the area where the maximum supply power rate
exceeds 16 as encircled by { in Figure 6-8, and their deviation from the standard
expression is large.

In the case of the maximum supply power rate exceeding 16, themeasurement is made under low load condition in which the load of switch circuit’s
secondary power is around 6% or less of the maximum supply power including PoE,
making the fixed power consumption of power supply dominant.
lowering the conversion efficiency as shown in Figure 4-9.

It also results in

Therefore, it becomes difficult

to perform calculation by the relational expression using the maximum supply power rate
(Pd/Ps).
Based on the study, since models with the above mentioned ratio of which exceeds 16
are not many and the shipment volume is low, it was decided that those with the above
mentioned ratio of which is within 16 are to be target products.
Figure 6-10 shows the standard value (baseline) of incrementation for products with
PoE defined by the relational expression (example of 100Mbit/s + 1Gbit/s).

The baseline

is not straight because the inverse number of the correction coefficient f(Pd) is taken.
Area above the dotted line is excluded from the target scope because the maximum supply
power ratio of 100Mbit/s × 24 + 1Gbit/s × 2 (expressed as 24 + 2G) exceeds 16 there.
Among existing products, only those with the maximum supply power rate up to 25
are available; however, it potentially becomes 40 or more depending on the specifications.
(For example, 100M × 8 ports of category D can have the maximum supply power up to
123.2W (=15.4W × 8), which results in the value to be 40 times compared with 3W of thepower consumption standard for power supply of the switch.)

In this area, power

consumption of PoE is extremely large compared with that of the switch.

Therefore, it isappropriate to review this area again when relevant products are introduced in themarket, while taking the efficiency improvement of power supply into consideration.
3. Supplementary explanation (details about expansion of expressions)(1) Parameters:
Pn: Additional power of PoE control circuit for each categoryPn =γn ⋅ Pd/Ps⋅ (αn ⋅ X + βn)1 − γn ⋅ Pd/Ps

Pd: PoE maximum supply power (based on the rated power)
Ps: Secondary power of switch circuit and PoE control circuit
However, the lower limit of 1 – γn ⋅ Pd/Ps shall be 0.4.

53

Ps: Secondary power of switch circuit and PoE control circuit (the power of circuit side
is called secondary power)
Ps = A+B
A: Secondary switch circuit power
A = Target standard value for products having port structure without PoE(αn ⋅ X + βn) × power supply efficiency 85%
B: Secondary PoE control circuit power (fixed value: 1.00 watt)

αn ⋅ X + βn : Standard power based on line speeds and their combinations(Shortened form of αn100M x100M + αn1G x1G + αn10G x10G + β n )γn: Correction coefficient (the lower limit of 1 – γn ⋅ Pd/Ps is 0.4, i.e. the upper limit of
the incrementation rate is 2.5)
(2) Concept of the relational expression
Based on the concept that the power for controlling PoE shall be added, the relational
expression is formulated as follows.
(αn ⋅ X + βn) / T + Pn / T.............. (1)Since nA = A + (n−1)A, the conversion of this relational expression becomes as follows.
(αn ⋅ X + βn) / T
1 − γn ⋅ Pd/Ps=

1⋅ (αn ⋅ X + βn) / T
1 − γn ⋅ Pd/Ps= (αn ⋅ X + βn) / T +1 − (1 − γn*Pd/Ps)⋅ (αn ⋅ X + βn) / T
1 − γn*Pd/Ps= (αn ⋅ X + βn) / T +γn ⋅ Pd/Ps⋅ (αn ⋅ X + βn) / T
1 − γn ⋅ Pd/Ps

Then,
Pn =

γn ⋅ Pd/Ps⋅ (αn ⋅ X + βn)1 − γn ⋅ Pd/Ps

Thus, the expression (1) is expressed this way.
Through this conversion, PoE control load power is now expressed as anincrementation, becoming easier to understand.

54

Attachment 7

Routers, etc. Evaluation Standard Subcommittee
Energy Efficiency Standard Subcommittee of the Advisory Committee for
Natural Resources and Energy
Background of Holding

First Subcommittee Meeting (July 19, 2005)• Disclosure of the Routers, etc. Evaluation Standard Subcommittee• Current status of routers and switches• Scope of targeted routers and switches
Second Subcommittee Meeting (September 13, 2005)• Scope of targeted routers and switches• Energy consumption efficiency and the measurement method for routers, etc.
Third Subcommittee Meeting (June 11, 2007)• Activities of the Routers, etc. Evaluation Standard Subcommittee so far• Review of measurement method for routers, etc.
• Scope of targeted small routers, etc.
Fourth Subcommittee Meeting (August 2, 2007)• Scope of targeted small routers, etc.
• Energy consumption efficiency and the measurement method for small routers,
etc.
Fifth Subcommittee Meeting (January 11, 2008)• Categories for target setting and target standard values for small routers• Categories for target setting and target standard values for L2 switches
Sixth Subcommittee Meeting (February 21, 2008)• Interim summary report

Interim report was open for public comments during the period from March 1, 2008
through March 30, 2008; and 1 comment was received.

Since it was not directly

related to the content of the interim report, no changes in the language was required.
As a result, the interim report was adopted as the final report.

55

Attachment 8

Routers, etc. Evaluation Standard Subcommittee,
Energy Efficiency Standards Subcommittee of the Advisory Committee
on Natural Resources and Energy
List of Members
Chairman: YUTAKA MATSUSHITA

Chairman, Forum for Agreeable Living withIntelligence, Communication & Electronics

Members: TADAHITO AOKI

Chief Researcher, Energy and Environment System
Laboratories, NTT (Attended from 3rd subcommittee
meeting)

AKIRA ISHIHARA

Standing Director, the Energy Conservation Center,
Japan (Attended from 3rd subcommittee meeting)

KAZUHITO OMAKI

Research Coordinator, National Institute of Advanced
Industrial Science and Technology

TSUYOSHI KINOSHITA

110Senior Director, Cisco Systems, Inc. (Attended
from 5th subcommittee meeting)

YOICHI SHINODA

Professor, Japan Advanced Institute of Science andTechnology, Information Science Center

SEIICHI SHIN

Professor, Electro-Communications Faculty, theUniversity of Electro-Communications

YUKIO NAKANO

Senior Researcher, Central Research Institute ofElectric Power Industry

TOSHIHISA MASUDA

General Manager, Technology Department, The
Energy Conservation Center, Japan (Attended 1st and2nd subcommittee meetings)

ITARU MIMURA

Chairman, Communications and Information
Network Association of Japan, Router & Switch
Technical Committee

MIKIO YAMASAKI

Chief Researcher, Energy System Project, Energy andEnvironment System Laboratories, NTT (Attended
1st and 2nd subcommittee meetings)

TOSHIHIKO YAMATO

Operating Officer on Alliance & Technology, Cisco
Systems, Inc. (Attended 1st through 4th
subcommittee meetings)

TAEKO YUINE

Executive Director and Consumer Consulting Office
Head, Nippon Association of Consumer Specialists

56Reference data 1
Current Status of Routers and Switches
1. Market trend
1.1 History of routers and switchesz

The first router in the world (1976)
Router is a device for transmitting packets defined by IP (Internet Protocol) to
destination computers according to their addresses.

It was produced by BBN Corp., U.S.A.

for the first time in 1976 to be used on the “ARPANET” which was the first computer
network in the world. Processing of routers was realized by software on general purpose
computers, and its performance was approximately 100 packet/s.
z

Routers sold for commercial purpose for the first time in the world (1986)“ProNET p4200”, the first commercial router in the world, was launched by Proteon
Corp., U.S.A. in January, 1986 as a multi protocol router which was capable of working
with protocols other than IP. 2 month later, Cisco Systems, Inc. U.S.A., which is a makerspecialized in routers, launched a multi protocol router “AGS”, and then routers rapidly
spread in the market. It was a dedicated device put in a box type enclosure, but theperformance was around 10k packet/s because, likewise in previous routers, it was using abus neck architecture where a line card for sending and receiving packets and a processor
were connected with one bus.

z

IP processing by hardware (first half of 1990s)
In 1990s, the internet started to be used actively for commercial purposes. Cisco
Systems, Inc. launched “Cisco 7000” in 1993 which achieved 270k packet/s by having the IP
processing then dominant done in hardware.

z

Rapid spread of internet and advancement of speed of routers (latter half of 1990s up to now)
As the internet spread rapidly, the traffic increased exponentially, and improvementof router speed was always requested.

In 1997, Cisco launched “Cisco 12000” using a

distributed architecture where a distributed processing of IP was carried out at hardwareof each line card.

In Cisco 12000, multiple line cards were connected with a cross bar

switch to solve the bus neck, and the performance finally achieved 10M packet/s.
Furthermore, Hitachi, Ltd. introduced GR2000 in 1998 which adopted a distributed
architecture and CRS-1 in 2004 which combined multiple enclosures and achieved theperformance of 100G packet/s.
Currently, new products are being developed to build the NGN (New Generation
Network) as well as in response to the advancement of speed and enlargement of capacityof the internet.
57

1.2

Forms of products

1) Router
Router is a communication device designed to relay data flowing on a network, which
is formatted according to an internet communication protocol, to other networks. It has aroute selecting function that judges which route should be used to send the data based on
the addresses in the network layer (IP layer).
2) Switch
Switch is a network relay device, and it is classified into Layer 2 switch, Layer 3
switch, and so forth according to the layer used to judge the destination of packet form data.
The switch which judges the destination of packets using the data (such as MAC address of
Ethernet) on the data link layer (second layer) of the OSI reference model is called Layer 2
switch.

Meanwhile, Layer 3 switch uses the data on the network layer (third layer) tojudge the destination of packets.

It utilizes IP and others which exist in the network layer.

(Note) OSI reference model
Figure -1 OSI reference model
Layer
Layer nameth
7 layer (Layer 7)
Application layer
6th layer (Layer 6)
Presentation layerth
5 layer (Layer 5)
Session layer
4th layer (Layer 4)
Transport layerrd
3 layer (Layer 3)
Network layernd2 layer (Layer 2)
Data link layer
1st layer (Layer 1)
Physical layer

1.3

Types of routers and switches

1) Routers
Cluster typeHigh reliability type

Popular type

Broadband

With external power
supply function

High-end devices which communication carriers use for backbone networks.
Devices where power supply, common control part and fan can be configured
redundantly. Based on the redundant parts, there are category I (all common
parts are redundant) and category II (only power supply is redundant).
Devices which do not belong to any of the cluster type, high reliability type or
broadband (mainly for enterprise use) as well as which do not have redundantconfiguration.
Devices with WAN side (less than 1 Gbps) × 1 port and LAN side × 2 ports ormore. However, configuration and management function by Telnet is notavailable. Based on the availability of wireless LAN function, there arecategory I (with wireless LAN) and category II (without wireless LAN).
Among the above types of routers, devices with power supply function forequipment connected.

58

Servers
L2 switches(without management function)

Network control management system

L3 switches

Internet data
centerPopular type routers

L2 switches
Certification(without management function)

High reliability routers

Companies

Cluster type routers

Broadband routers

Cluster type routersHigh reliability routersHome

L3 switchesHigh reliability routers
Popular type routers

Access network

Carrier network

Figure-2

IP network architecture

Figure-2 shows an IP network architecture composed of routers and switches.
Current IP network includes carrier IP networks composed of carrier ISPs (Internet
Service Providers) and access networks connecting homes or companies with the IP
network.

The carrier IP network is a network provided by communication carriers.

access network is a network connecting homes or companies with the carrier ISP.

The

Clustertype routers and high reliability type routers are mainly used in the carrier IP networks
and the internet data centers.

Broadband routers are mainly used at homes, and popular

type routers are used in SOHOs and enterprise networks.
2) Switches• Layer 2 switches: Switches which judge the destination of packets from the data (suchas MAC address of Ethernet) on the data link layer (note) (second layer) of the OSI
reference model.
• Layer 3 switches: Switches which send packets judging the destination from the data on
the network layer (third layer), such as IP etc. present on the network layer.

59

Figure-3

Typical routers and switches

Routers

Product image(Outer dimensions are those of typical model expressed in W × D × H, mm)

Cluster type router(Outer dimensions: 599 × 914 × 2134) (Cisco Systems)

High reliability typerouter(Outer dimensions: 440 × 490 × 441) (ALAXALA Networks)60

High reliability typerouter(Outer dimensions: 440 × 678 × 101) (ALAXALA Networks)

Popular type router(Outer dimensions: 220 × 141.5 × 42.6) (YAMAHA)

Broadband router(wired)(Outer dimensions: 88 × 26 × 138) (corega)

Broadband router(wireless)(Outer dimensions: 153 × 111 × 28) (I-O Data Device)(Outer dimensions: 28 × 144 × 130) (BUFFALO)

61

Switches

Product image

Layer 2 switch(Outer dimensions: 446 × 380 × 43) (ALAXALA Networks)(Outer dimensions: 436 × 450 × 44) (Hitachi Cable)

Layer 3 switch(Outer dimensions: 443 × 544 × 395) (ALAXALA Networks)(Outer dimensions: 440 × 352 × 44) (Allied Telesis)

62

1.4

Status of domestic shipment

As the internet rapidly spreads, the domestic market size for routers and switches isdrastically growing. This is likely to continue hereafter.
1) Market trend as a whole
Overall shipment size of routers and switches in the domestic market are indicated by
the number of units and by the number of ports below. It is estimated that the number ofrouters shipped in FY2012 will be 1.5 times more than in FY2006; and similarly it isexpected to be 1.3 times more for switches.
Figure-4

Changes of domestic shipments of routers and switches(Unit: 1,000 units for routers, 1,000 ports for switches)

2004
2005
2006
2007
2008
2009
2010
2011
2012
Fiscal year
ActualActualActualEstimation Estimation Estimation Estimation Estimation Estimation
Routers
3,360
3,980
4,268
4,789
5,123
5,364
5,661
5,992
6,517
Switches
30,69031,97031,84033,51035,51037,39038,99040,73042,350Source: “Mid-term demand estimation of communication equipment, FY2007” CIAJ
The numbers are the total of voluntary statistics by CIAJ based on voluntary responses from the member companies
and demand estimations for products not covered in the CIAJ statistics.

2) Trend of routers by product category
Changes of domestic shipments of routers by product category are shown below. With
respect to the actual shipment numbers in FY2006 by product category, broadband routers
account for 91% of the total.
Figure-5

Changes of domestic shipments of routers by product category

Fiscal year
Cluster typeHigh reliability type
Popular type
Broadband
With external power
supply function

2004
Actual
10
60
270
2,990

2005
Actual
1
60
329
3,559

30

31

(Unit: 1,000 units)

2006
2007
2008
2009
20107
2011
2012
Actual Estimation Estimation Estimation Estimation Estimation Estimation
1
1
1
1
1
1
1
62
62
62
63
65
66
66
259
230
215
200
190
175
160
3,885
4,419
4,760
5,005
5,295
5,635
6,170
61

77

85

95

110

115

120

Total
3,360
3,980
4,268
4,789
5,123
5,364
5,661
5,992
6,517
Source: “Mid-term demand estimation of communication equipment, FY2007” CIAJ
The numbers are the total of voluntary statistics by CIAJ based on voluntary responses from the member companies
and demand estimations for products not covered in the CIAJ statistics.

千台
1,000 units

Figure-6

Graph of changes of domestic shipments of routers by product category
Clustertype
クラスター型7,000

High
reliability type
高信頼
Populartype
普及型
Broadband
ブロードバンド

6,000

With
external power supply function
外部電源供給機能付

5,000

4,000

3,000

2,000

1,000

0

2004
2004年
Actual
実績

2005
2005年
Actual
実績

2006
2006年
Actual
実績

2007
2007年
Estimation
予測

2008
2008年
Estimation
予測

2009
2009年
Estimation
予測

63

2010
2010年
Estimation
予測

2011
2011年
Estimation
予測

2012
2012年
Estimation
予測3) Trend of switches by product category
Changes of domestic shipments of switches by product category are shown below. In
terms of the ratio of actual numbers of ports in FY2006, L2 switches accounts for 86% of thetotal.
Figure-7

Changes of domestic shipments of switches by product category(Unit: 1,000 ports)

Fiscal year
L2
L3
With external power
supply function

2004
Actual
26,4702,550

2005
Actual
27,560
2,650

1,670

1,760

2006
2007
2008
2009
2010
2011
2012
Actual Estimation Estimation Estimation Estimation Estimation Estimation
27,66028,63029,88031,01031,73032,78033,700
2,430
2,760
3,130
3,520
3,910
4,150
4,450
1,750

2,120

2,500

2,860

3,350

3,800

4,200

Total
30,69031,97031,84033,51035,51037,39038,99040,73042,350Source: “Mid-term demand estimation of communication equipment, FY2007” CIAJ
The numbers are the total of voluntary statistics by CIAJ based on voluntary responses from the member companies
and demand estimations for products not covered in the CIAJ statistics.

1,000 千ポート
ports

Figure-8Graph of changes of domestic shipments of switches by product category
With external power

外部電源供給付
supply function
L3
L2

45,00040,00035,00030,00025,00020,00015,00010,000
5,000
0
2004
2004年
Actual
実績

2005
2005年
Actual
実績

2006
2006年
Actual
実績

2007
2007年
Estimation
予測

2008
2008年
Estimation
予測

64

2009
2010
2009年
2010年
Estimation
Estimation
予測
予測

2011
2011年
Estimation
予測

2012
2012年
Estimation
予測

1.5

Major domestic and overseas manufacturers shipping products to the domestic market
Table-9 shows major manufacturers of routers and switches.

Figure-9 Major manufacturers shipping products to the domestic market (in the order of theJapanese syllabary)

RoutersI-O Data Device, Allied Telesis, ALAXALA Networks, Corega, Cisco Systems(overseas), Juniper Networks (overseas), NEC, Buffalo, Hitachi, FURUKAWA
ELECTRIC, Fujitsu, YAMAHA

Switches

Allied Telesis, ALAXALA Networks, Extreme Networks (overseas), SII Network
Systems, Corega, Cisco Systems (overseas), Hewlett-Packard Japan (overseas),
NEC, Buffalo, Hitachi Cable, Foundry Networks (overseas), Fujitsu, Matsushita
Network Operations

65

Reference data 2
Glossary
NO
1

2

Term

Meaning

ACL

List that describes packet processing methods, resources for the(Access Control List)

processing, etc. for network equipment such as routers and switches.

ADSL

Communication method that enables high-speed data communication(Asymmetric Digitalof some to some tems of Mbit/s using copper subscriber lines which are

Subscriber Line)laid from telephone stations to each household or company office.
wasdevelopedaround

1990.

While

the

high-speed

It

data

communication is realized using already laid 2-core copper lines, inmost cases it can be used only within the area of some km away fromthe telephone station because, as the distance becomes longer, themaximum transmission rate goes down affected by attenuation ornoise.

As its name “asymmetric” indicates, it uses asymmetriccommunication method, with which the data transmission speed isdifferent between the downward direction, i.e. from the telephonestation to users, and the upward direction.
3

4

ASIC

Collective name for ICs designed and manufactured for specific(Application Specificapplications. It includes full custom LSI, gate array, standard cells,

Integrated Circuit)

etc.

ATM

Transmission method where different types of information such as(Asynchronous

data and sound are divided into cells of 53 byte fixed length and sent.

Transfer Mode)

The cells are sent only when there are data to be send; therefore, it iscalled “asynchronous”.

The destinations are sorted by an exchanger

called ATM switch.

This is used to effectively utilize high-speedtransmission such as optical fiber.
5

6

7

CODEC

Devices and softwares which can code and decode data in a

(Coder Decoder)bi-directional way using an encoding method.

CPU

CPU is a key circuit for computers which executes various computing,(Central Processing Unit)

information processing, product control, etc. according to programs.

DC-DC conversion

Efficiency of voltage conversion from DC to DC.

efficiency
8

DSLAM

Device that aggregate DSL lines and relays to high-speed back-bone(Digital Subscriber Linelines.

Access Multiplexer)
9

DSP

Microprocessor dedicated to processing of digital signals and capable(Digital Signal Processor)of high-speed data processing.

66

NO
10

Term

Meaning

FTTH

A plan to build a high-speed communication environment using(Fiber To The Home)

optical fibers for the access network connecting the subscriber lines
from telephone stations to each home.

It started when Southern

Bell, a local telephone company, tested it in Florida in 1986. In 1994,
NTT started to promote the FTTH aiming to change all lines to opticalfiber by 2010 in Japan. (It was requested to be completed by 2005 at
the government’s economic policy ministers’ meeting in 1997.)
11

HomePNA

HomePNA is the standard for connecting to the internet using(Home Phone Network

telephone lines in homes.

Alliance)
12

IEEE802 committee

IEEE is the Institute of Electrical and Electronics Engineers in U.S.
802 committee is its sub-group responsible for the standardization of
LAN etc.

13

IEEE802.11n

One of the wireless LAN standards expected to be finalized by IEEEin the latter half of 2008.
100Mbps or above.

The effective rate is expected to be

It enables high-speed wireless communication

based on MIMO (Multiple Input Multiple Output) which executes
sending and receiving of data using multiple antennas.
14

IETF

An international organization developing technical standards (mainly(Internet Engineering Task architectures and protocols) to be used on Internet.
Force)
15

Interframe GAP

Gaps between frames containing information.

It is required to be at

Gap between frames (GAP) least 12 bytes for Ethernet. Frame length does not include gaps.

16

IP

Protocol of the network layer (third layer) of the OSI reference model.

(Internet Protocol)

It executes the best effort type datagram-oriented communication
between two nodes based on IP addresses assigned to each node on
the network.
Since IP is the best effort type datagram-oriented communication, it
may happen that packets do not reach the intended destination or
multiple packets are delivered there.

Resending of undelivered

packets, etc. in such cases are all controlled by the higher protocols(TCP: Transmission Control Protocol, etc).

67

NO
17

Term

Meaning

IP-VPN

VPN (Virtual Private Network) using the private IP network of(Internet Protocol-

communication carriers as the communication route.

Virtual Private Network)

internet which needs to go through multiple providers’ networks is not

Since theused here, the end-to-end IP connection with high confidentiality andgood communication quality can be realized.
18

IP telephone service

Utilizing the VoIP technology, voice communication system is built on
IP network. Each service provider provides a telephony service tousers, and normal telephones are utilized as terminals.

19

IPSec

Encryption protocol to provide falsificationproof and confidentiality
for data in IP packet unit using encrypt technology.

20

L2/L3

L2 is the abbreviation of Layer 2 expressing the data link layer(Layer 2/second layer) of the OSI reference model.
L3 is the abbreviation of Layer 3 expressing the network layer (Layer
3/third layer) of the OSI reference model.

21

22

L2TP

One of the tunneling protocols standardized by the IETF (Internet(Layer 2 TunnelingEngineering Task Force).

Protocol)Private Network).

LAN

The network which connects computers on the same floor, in the same

(Local Area Network)building or in the neighboring buildings with a relatively high-speed

It is mainly used for the VPN (Virtual

data transfer means such as Ethernet.
23

LLC

Among two sub-layers of the second layer (data link) of the OSI(Logical Link Control)reference model, LLC layer is the higher one with functions such as
error control and frame control.

24

MAC

Address for controlling access to media and unique to every NIC(Media Access Control)(Network Interface Card).

MAC address(data link layer) in the OSI reference model in terms of computer
network technology.

It is the sub layer of the second layer

In the case of Ethernet, MAC address is 48bits,

where the first 24bits is the address unique to each vendor managed
by IEEE (Institute of Electrical and Electronics Engineers, U.S.A.)
and the last 24bits is the number unique to each NIC. There are no
NICs in the world which have the same MAC address.

Ethernet

sends and receives data based on these MAC addresses.

A switchwith management function has at least one MAC address.

A routerhas the number of MAC addresses which combines the number of
WAN and one of the LAN sides.

68

NO
25

Term

Meaning

ONU

Terminator installed at the terminal side (home side) in the optical(Optical Network Unit)

fiber communication (FTTH).

It converts the optical fiber

communication to Ethernet, etc.
26

OSI

A protocol system where computer communication methods are(Open Systemprovided for each layer by ISO (International Organization forInterconnection)

Standardization) so that communication among computers can berealized between different vendors.

There are seven layers, andthe TCP/IP (Transmission Control Protocol/Internet Protocol) has
become the de facto standard of communication protocol as Internet
spreads and expands.
27

PBX

Telephone exchange in premises, i.e. relay device connecting multiple(Private Branch eXchange) telephones in premises (internal phones) to public telephone
networks.
28

PLC

Technology

using

power

(Power Linecommunication lines.

(electric

light)

lines

in

homes

as

Communication)
29

PoE

Technology providing power to terminals, etc. through stranded cables(Power over Ethernet)(UTP) which are used for cabling of Ethernet.

It has beenstandardized as IEEE 802.3af. Examples of the powered terminals
are IP telephones, network cameras, switching hubs, wireless LAN
access points, etc.
30

PPPoE

Technology by which frames based on PPP (protocol for realizing(Point to Point Protocol

TCP/IP connection with telephone lines and modems) which isover Ethernet)

normally used for dial-up connections are capsulized with Ethernet
frames and sent through Ethernet.

31

PPTP

PPTP is mainly used for remote access.

It is a tunneling protocol(Point to Point Tunnelingwhich Point to Point Protocol (PPP) is extended to become.

Protocol)32

preamble

Preambles (8 bytes) are attached to the heads of frames flowing on
Ethernet but are not included in the frame length. Preambles areused to find a lead of signals at a receiving part and also used as a
trigger to regenerate clock.

33

RFHigh frequency signals for wireless communications, etc.

(Radio Frequency)

69

NO
34

Term
SLIC

Meaning
Interface for telephone line.

(Subscriber-Loop-InterfaceCircuit)

35

SNMP

Protocol providing the communication method for controlling and( Simple Network

monitoring communication devices on IP network.

Management Protocol)

36

SOHO

SOHO refers to offices with small number of workers or self-employed(Small Office /individuals working at home. This term is often used in contrast

Home Office)with large companies. Thanks to the improved cost performance of
personal computers, increasing numbers of small offices belonging tosmall-to-medium-sized businesses and personal users can now afford
to introduce computers or even utilize LAN.

Although the size of acomputer system introduced into a SOHO is not large compared withthat of a large company, the share by SOHO in the personal computer
marketisanything

but

small

becausethenumberofsmall-to-medium-sized businesses and self-employed individuals arequite large.
37

SSL

Protocol providing safe communications by means of encrypting(Secure Sockets Layer):information on the internet.

VPN using SSL is called SSL-VPN.

SSL-VPN
38

TTL

TTL is the value described in IP header. Every time a packet passes(Time to Live)through a router, 1 is subtracted.

Endless looping of packets isavoided by disposing packets when their TTL becomes 0.
39

VoIP

Technology realizing voice communication on IP network.

It is(Voice over IP)

intended to reduce the communication cost as a result of raising line
operation rate by means of integrating the intrastructures oftelephone network and data network.

It frequently refers to thesystem for companies designed to enable telephone-to-telephone callsby connecting LAN-to-LAN with data communication networks.
40

VPN

Technology enabling many subscribers to use a public communication(Virtual Private Network)

network as if it is for their own use, instead of using dedicatedcommunication lines.

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Typical usage is for LAN-to-LAN connections.

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Term

Meaning

WAN

Term normally used in contrast with LAN, meaning networks(Wide Area Network)

covering wide areas by connecting computers (LANs) located inremote areas from each other.

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Web

A document system developed by CERN (European Center for Nuclear(World Wide Web)

Research).

It allows jump commands to other documents to beembedded in a document. Using URL (Uniform Resource Locator) as
this jump command, users can jump to any document in WWWservers in the world which are participating in the internet.
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xDSL

Collective

name

of

the

technologies

thatrealizehigh-speed(x Digitalcommunication using twist pair cables.

Subscriber Line)these technologies are installed at the telephone station side and the

If only devices supporting

subscriber side, communication lines as high-speed as digital lines
can be realized through the existing telephone lines.

Typicaltechnology is ADSL that realizes faster downward transmission rate.
Other technologies such as RADSL, HDSL, VDSL, etc. are also
included under this collective term.
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Ethernet

A standard of communication method invented by Palo Alto ResearchCenter, U.S. Xerox and stadardized by the IEEE (Institute ofElectrical and Electronics Engineers).

It stipulates communication

speed, cables used for the communication, methods for sending andreceiving data.

Many of the communication systems currently being

used in and out of Japan comply with this standard. 10BASE-T and
100 BASE-T used for company’s internal LAN are also complying withthis standard. The IEEE is an academic organization working on thedevelopment of industrial standards.

The 802.3 committee underIEEE continues to study Ethernet.
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Internet VPN

Among VPNs (Virtual Private Network), this term refers to the one(Internet

executed through Internet. IP packets for LAN are capsuled with IP

Virtual Private Network)

headers for Internet in order to be sent/received, because the IP
address information used for LAN are usually different from the oneused for Internet.

46

Throughput

Data transmission rate among network systems.

Specifically, it

refers to the system’s effective transmission rate such as filetransmission rate between terminals.
unit.

Mainly bit/s is used as theThroughput varies according to various factors such as CPU

capacity, memory capacity, speed of relays, traffic; therefore, caution
should be exercised when measuring the throughput.

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47

Term
Dial up

Meaning
The method with which users log in remote computers or utilize
resources of those computers through public lines, modems and the
like.

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Dial up RouterThis is also called remote access.

Routers

equipped

with

dial

up

connection

function.

The

communication cost due to connecting to public lines can be saved byconnecting to external networks only when necessary. The operation
is easy for users, because the connection and disconnection are done
automatically.

Since dial up routers are usually equipped withreceiving function also, they can be used as connection servers for dialup connection requests from outside.

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Traffic

It originally means “transit, going and coming back”, but, in the fieldof telecommunication, it means going and coming of packets flowing
on networks. The condition where a great deal of data is flowing on
networks and congested is described “the traffic is big”.

To thecontrary, the condition where there is few data flowing on networks is
described as “the traffic is small”.
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Network Processor

Dedicated processors designed to execute high-speed processing forhighend communication service such as security, encrypting, traffic
control and to be appropriate for network equipment such asbroadband routers and wireless LAN access points.

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Hub

Also called the concentrator.

In the case of cabling based on

10BASE-T, the network is constructed by connecting nodes around a
hub in the shape of star.

The parts to which modular jacks of

10BASE-T cables are connected are called ports, and there arevariations, such as 4, 8, 12, 16, 24 ports, based on the size of the hub.
The advanced hub which has overcome weakness of conventional hubs
and is equipped with a function to learn MAC addresses and atransfer function is called switching hub.

They have developed intocurrent L2/L3 switches as the speed becomes faster.
52

Fast Ethernet

Collective name of standards of Ethernet, such as 100BASE-T and
100VG-AnyLAN, with the transmission rate (100Mbit/s) which is 10
times faster than that of ordinary Ethernet.

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53

Term
Frame

Meaning
The unit of signals sent through the data link layer (second layer) of
the OSI reference model. Although this term is used synonymouslywith packets, in fact IP packets are capsulized with Ethernet frames.

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ProtocolRules or agreements for data communication among computers.
Internet is based on the protocol called TCP/IP (Transmission Control
Protocol/Internet Protocol).

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HeaderCharacter string placed at the head of packets, managing various
information such as sender’s address and receiver’s address.

Routers

and switches send packets to proper receivers based on this header
information.
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Modem

Device enabling computers to communicate with each other throughtelephone lines by means of converting digital signals to analog
signals (vice versa).

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Routing

Route control, by which, looking into the destination information of
the packets sent out on the network, routes are controlled so that thepackets will arrive at destination devices properly.

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Redundancy

To construct a system with equipment of slightly more than necessary
so that the system can continue to provide service even if a part of theequipment goes down.

For example, a network redundancy isrealized by prepareing multiple access lines to Internet so thattroubles can be avoided even if one of the lines is disconnected; andanother type of redundancy is similarly realized by preparing
multiple devices in a system to avoid any troubles.
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Wireless LAN

LAN in which communications are performed using wireless meassuch as radio waves or light instead of wired cables.

When

supporting products were launched by each company in 2000, it
started to spread rapidly.

Since wired cable laying is not required, it

can save the effort to lay the cables anew when desks are moved in an
office for repositioning for example.

There is also a growing need for

wireless LAN in homes where it is difficult to lay cables.

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