1、 International Telecommunication Union ITU-T Series LTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 1(02/2013) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT ITU-T L.1310 Supplement on energy efficiency for telecommunication equipment IT
2、U-T L-series Recommendations Supplement 1 L series Supplement 1 (02/2013) i Supplement 1 to ITU-T L-series Recommendations ITU-T L.1310 Supplement on energy efficiency for telecommunication equipment Summary Telecommunication technologies play a large and increasing role in modern society; we depend
3、 increasingly on constant streams of information in our work and free time for data access and entertainment. Every day, more people access high speed networks via wired and wireless channels, and the amount of energy to deliver all those new services is also growing rapidly. Without an increase of
4、energy efficiency, this would lead to a dramatic increase in energy use for all new services and customers. Scaling existing technological solutions is not enough. Not only do we need to implement changes in energy efficiency but we also have to implement them rapidly. This Supplement on energy effi
5、ciency for telecommunication equipment reviews the concepts for energy efficiency in application to networking devices; it presents a concept of place in a network as a base for classification, describes a process for creating a single metric for energy efficiency which reflects the qualities of equ
6、ipment scalability with traffic levels and provides testing topologies and traffic pattern descriptions. History Edition Recommendation Approval Study Group 1.0 ITU-T L Suppl. 1 2013-02-07 5 ii L series Supplement 1 (02/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nat
7、ions specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations
8、 on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval o
9、f ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the expression “Administration“ is u
10、sed for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the pub
11、lication is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the publication is required of any party.
12、 INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights,
13、 whether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementers are cautio
14、ned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of IT
15、U. L series Supplement 1 (02/2013) iii Table of Contents Page 1 Scope 1 2 Abbreviations and acronyms 1 3 Definitions 1 4 Understand network functionality 1 5 Measure energy usage. 2 6 Analyse network architecture and components 2 7 What is energy efficiency? . 2 8 Power measurement conditions 3 9 Po
16、sitioning in the network and energy efficiency 3 10 Metric definition: Compare products at points in the network . 4 Bibliography. 7 iv L series Supplement 1 (02/2013) Introduction Telecommunication technologies play a large and increasing role in modern society; we depend increasingly on constant s
17、treams of information in our work and free time for data access and entertainment. Every day, more people access high speed networks via wired and wireless channels, and the amount of energy to deliver all those new services is also growing rapidly. This would lead to a dramatic increase in energy u
18、se for all new services and customers. Scaling existing technological solutions is not enough. Not only do we need to implement changes in energy efficiency, but we also have to implement them rapidly. In order to understand if the speed of change is sufficient, we need to evaluate the energy effici
19、ency of the products that are used to build new telecommunication equipment and then compare it to existing solutions. This process highlights the necessity to have reliable and consistent methods and metrics for energy efficiency evaluation. In recent years, interest in improving energy efficiency
20、of all energy consuming products has become a hot topic for all society and for the business community in particular. This interest can be attributed to two major factors: concern regarding global warming contributions, and the high price of energy. Both are fair concerns and both require fast actio
21、n. Networks have increased significantly in utility and capacity and are now a critical feature of most businesses. However, the energy consumed by networks has also increased, and it is estimated now to represent as much as 10% of all ICT energy usage. Network users, service providers and regulator
22、s are looking for ways to reduce or limit the growth of network energy usage without losing critical network functionality. This will require a focus on the energy efficiency of the network installation, with a particular attention to the energy used and the service delivered by the networking produ
23、cts and supporting infrastructure. The first instinctive action for energy efficiency improvement is to reduce the nameplate power rating for any product. However, while the actual power rating of a product is an important characterization, its use is limited to facility wire provisioning and does n
24、ot consider what the product actually does. How many useful features does the product have? How does it compare with the previous generation of products? What are the new functions, features, services it brings? What is its power in the real network? Generally, the first step in improving energy eff
25、iciency should always be to define the meaning of energy efficiency and measure current energy usage in order to see where efficiency gains will have most of the impact and to quantify the effects of those efficiency gains. It should be expected that these efficiency gains will be in the production
26、network equipment as well as in the supporting infrastructure and the interactions between the two. Continuing energy efficiency improvements will require an examination of the procurement and provisioning process to ensure that new equipment that is added to the network or the infrastructure works
27、to maximize the efficiency of the system as a whole. There may be times when particular sets of products must be compared with each other for energy efficiency. It is important that this comparison is made in a manner that demonstrates the best energy efficiency without compromising the critical fun
28、ctions or performance of the network. Often there is a strong desire to have a single metric that would give a representation for energy efficiency, similar to the miles per gallon for cars. This may be bits per second per watt or an equivalent for networking. The problem with this approach is that
29、a car has only one major function: to take you from one point to another. Networking equipment, on the other hand, not only controls the flow of information, but also performs additional tasks including encryption, packet inspection and quality of service support. Sometimes a metric expressed in wat
30、ts per port (or similar) is proposed; but again, it does not reflect the nature of the port, its function, its throughput or how it relates to the rest of the network. Does this mean that a single metric is unusable? No, it L series Supplement 1 (02/2013) v simply means that both parts of a metric t
31、hroughput and power (consumed energy rate) must be carefully defined for specific network functions and positions in the network and the results compared for similar products only. L series Supplement 1 (02/2013) 1 Supplement 1 to ITU-T L-series Recommendations ITU-T L.1310 Supplement on energy effi
32、ciency for telecommunication equipment 1 Scope This Supplement on energy efficiency for telecommunication equipment reviews the concepts for energy efficiency in application to networking devices; it presents a concept of place in a network as a base for classification, describes a process for creat
33、ing a single metric for energy efficiency which reflects the qualities of equipment scalability with traffic levels and provides testing topologies and traffic pattern descriptions. 2 Abbreviations and acronyms This supplement uses the following abbreviations and acronyms: EER Energy Efficiency Rati
34、o EUT Equipment Under Test IMIX Internet Mix LAN Local Area Network NAS Network Applications Service RF Radio Frequency SNE Small Networking Equipment TEER Telecommunications Energy Efficiency Ratio WAN Wide Area Network 3 Definitions 3.1 active mode: Mode in which the equipment is fully functional
35、and can pass traffic. It is also known as On Mode or Ready. 3.2 idle mode: The same as active mode, with no user data traffic. 3.3 stand-by mode: Mode in which the equipment is not functional, only the reactivation option is available. 3.4 networking device: Device with at least two network interfac
36、es and whose primary function is to pass data. 3.5 networked device: Device which uses the network to perform or improve a primary function. Examples are: IP phone, network applications service (NAS). 4 Understand network functionality Once energy efficiency has been optimized, the next step towards
37、 energy conservation is to understand the functionality of the network. Attempting to implement energy savings that compromise the functionality of the network will result in conflicting business objectives. This is especially true as networking functions have become critical to many, or even most b
38、usinesses. In many cases, network functionality is directly related to the revenue and profitability of the business. If the business goal is to sell network services or services over networks, then any loss of productivity for the network will result directly in lost revenue or customers for the bu
39、siness. The 2 L series Supplement 1 (02/2013) network may be critical to the business functionality in other cases where the business is not directly related to the network because the critical business systems rely on the network. Therefore, it is of utmost importance to understand the productivity
40、 and critical requirements of the network to avoid the risk of a major negative impact from (relatively) minor energy savings. 5 Measure energy usage The most important step is to measure where the energy is being used in the network. How the energy is used will vary not only according to applicatio
41、n or network type, but it will also differ from one individual network to the other. These variations can be due to different load requirements, physical infrastructures and environmental factors as well as time of day/week/month/year. Measuring where the energy is being used will highlight the area
42、s where the greatest energy savings may be made, as well as allow accurate cost analysis. 6 Analyse network architecture and components After analysis of network energy usage and critical functions, enhancements to the network infrastructure, architecture and components may be assessed. At this poin
43、t, there may be some key components that can be identified as targets for replacement in order to save energy; however, in most cases, significant savings will require evolution of system-wide features. The most important step at this stage is to understand how the interaction of components througho
44、ut the network and supporting infrastructure affects overall energy consumption. This will invariably be the most complex step and will require cross-functional expertise. In most cases, this will take the form of multiple initiatives and system-wide feature requirements that will be built into guid
45、elines and component requirements used during the evolution and upgrade process. 7 What is energy efficiency? Energy efficiency is a widely used term with multiple meanings: for example, one may hear phrases like “use the stairs, be energy efficient“, “energy efficient office or house“, or many othe
46、r phrases related to energy efficiency. In referring to electrical devices, it is convenient to start with a generic definition for “Energy Efficiency“ that applies to any device that uses energy to do work: “Percentage of total energy input to a machine or equipment that is consumed in useful work
47、and not wasted as useless heat.“ This could be expressed as follows: = nullnullnullnullnullnullnull(1) where Poutis the energy needed to do useful work, and Pinis the total energy. Equation 1 can work very well for devices such as power supplies or transformers where input and output can be measured
48、 in the same units. By definition, “Energy Efficiency“ is always in the range from 0 to 1, or 0 to 100% (if expressed as a percentage). However, for networking devices pure energy conversion is usually not considered as a useful function, except for some radio frequency (RF) devices. For example, in
49、 a typical router or switch, power Pinwould be in kilowatts (kW) and Pout(the signal transmitted) would be in milliwatts (mW). It can be easily seen that power conversion in networking devices is not a major function; data processing, depending on device type, is the major function instead. Therefore, it is necessary to decide what can be used as a representation (or a proxy) for Pout (the useful work). For packet switching equipment, it is very common to represent performance as maximum throughput: i.e., the sum of throughput on all system ports in the e
