Network Working Group B. Nordman Internet-Draft Lawrence Berkeley National Intended status: Informational Laboratory Expires: January 6, 2011 R. Winter NEC Labs Europe July 5, 2010 Considerations for Power and Energy Management draft-norwin-energy-consider-00 Abstract With rising cost and an increasing awareness of the environmental impact of energy consumption, a desirable feature of networked devices is to be able to assess their power state and energy consumption at will. With this data available, one can build sophisticated applications such as monitoring applications or even active energy management systems. These systems themselves are out of scope of this memo, as it discusses only considerations for the monitored devices. Implementation specifics such as the definition of a Management Information Base are also outside the scope of this document. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 6, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents Nordman & Winter Expires January 6, 2011 [Page 1] Internet-Draft Consider Energy July 2010 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Overview/Goals . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Scope of devices . . . . . . . . . . . . . . . . . . . . . . . 6 5. Energy Manangement . . . . . . . . . . . . . . . . . . . . . . 7 5.1. Device Considerations . . . . . . . . . . . . . . . . . . 7 5.2. NMS Considerations . . . . . . . . . . . . . . . . . . . . 7 5.3. MIB Considerations . . . . . . . . . . . . . . . . . . . . 8 5.4. Power State Monitoring . . . . . . . . . . . . . . . . . . 8 6. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 8. Normative References . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Nordman & Winter Expires January 6, 2011 [Page 2] Internet-Draft Consider Energy July 2010 1. Requirements notation The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. Nordman & Winter Expires January 6, 2011 [Page 3] Internet-Draft Consider Energy July 2010 2. Overview/Goals This document aims at framing and recording the discussions on power and energy management within the IETF. To this end, it clarifies terminology that most people believe have a well-defined meaning, which in practice however can mean vastly different things. The document further describes how energy and power reporting differs from other reporting tasks that have been defined by the IETF (e.g. IPFIX) and the resulting implications for mechanisms the IETF will define in the future. This document is intended to be a living document that also tries to capture why certain decisions were made in the process of defining power and energy management mechanisms. Another goal is to present use cases that go beyond the 'traditional' IETF ones to keep emerging standards open with respect to these use cases. In this memo, we focus on power monitoring only. Participating entities are monitoring systems that receive information and networked devices that provide information on energy consumption and power state information concerning themselves or potentially also other devices. Not in the scope of this memo are means for controlling the energy consumption and the power state of monitored devices. It is assumed that devices will manage their own power state, or if done externally, by proprietary and standardized solutions (that are or will become available), or as a consequence of functional applications. Nordman & Winter Expires January 6, 2011 [Page 4] Internet-Draft Consider Energy July 2010 3. Terminology Discussions about energy consumptions and device power states are often confusing as different products define states such as 'stand-by' quite differently. Even the same class of devices often implement such states differently. Named power states are intrinsically difficult to define consistently as they imply not only something about a device's energy consumption but also something about the device's capabilities in that state. To avoid confusion based on a different understanding of certain terms, we first define the meaning of certain terminology used in this document. In this document, we synonymously use the terms Power Mode and Power State; named modes are general categories. Some well-known power states have been used and have been (re-)defined in different contexts over the years, which make them unsuitable for discussion in a general context. Most prominently 'standby' has very different meanings and implications across a broad set of devices from TV sets to servers. We therefore deliberately do not refer to standby in this document. Within this document we restrict ourselves to a small set of named power state categories which are broadly understood, which however contain a large potential set of different power states themselves. These categories are on, off and sleep. In general, devices that are asleep will be able to wake quickly and will retain network connectivity. Devices that are off usually take much more time to turn on than the wake time and usually lack network connectivity. Devices that are on are fully functional but potentially with reduced performance. The organizing unit for power is a single device with one or more power sources. The term "product" is sometimes used as a synonym, and also covers the case in which a device proxies network presence including power reporting for a second device. Nordman & Winter Expires January 6, 2011 [Page 5] Internet-Draft Consider Energy July 2010 4. Scope of devices All devices that have a network connection should be in scope. While first adopters will surely be devices such as switches, routers, and servers (some of which already report power levels and power state through proprietary means), in the future networked electronic devices, appliances, and even lights will need such capability too. These devices may have different ways of accomplishing discovery and management for functional purposes, but will share the common energy/ power reporting capability. While some of these will directly measure power, other devices will not measure their power, but may be able to reliably estimate it. These devices are still in scope. Nordman & Winter Expires January 6, 2011 [Page 6] Internet-Draft Consider Energy July 2010 5. Energy Manangement First and foremost, the task of power and energy management is reporting. While a more active role in energy management is conceivable by e.g. putting devices into power states based on policies or other predefined schemes at a network management system (NMS), this document focusses on the reporting side of things. 5.1. Device Considerations There should not be an assumption that power state management of devices is done externally/centrally as ideally most devices will manage their own power state (distributed intelligence). This document does not address the power consumption levels of internal components of a product, only the energy inputs to the entire product (and net consumption if it provides power to other products). Simple devices from a network perspective such as appliances would benefit from a simple identification capability that would directly or indirectly reveal the brand/model of the device, and possible a URL to further information about the device. An example of this is the "Universal Product Code" on many products. Subsequent documents should identify the appropriate mechanism to accomplish this, e.g. an existing MIB. An energy management application could then obtain current energy use for a device like a refrigerator, and compare it to what it is expected to use under normal operation, and alert the building manager if it is significantly out of range. This also can be used to quickly inventory energy-using products in a building, and to summarize by product type where energy is being used. 5.2. NMS Considerations A Network Management System is the entity which collects the reported energy and power reporting data and uses it for 'advanced' applications. One such application could be to correlate energy consumption with some other metric to display some form of efficiency metric (like watthours/bit) if deemed useful. A second role an NMS could fulfill is to set device policies to control larger networked systems such as a data center. (Note: unclear whether the same channel should be used for setting and reporting). An NMS will usually query MIB data on a periodic basis, with that period dictated by its needs, possibly being dynamic. MIBs can provide an energy "meter reading" to lead to energy use for each period. Thus, the NMS does most of the work to generate time series energy data, and this minimizes burden on the host and the complexity of the Power MIB. Nordman & Winter Expires January 6, 2011 [Page 7] Internet-Draft Consider Energy July 2010 The first core function of the power monitoring are to maintain meters of energy use and of time in different power states (and through summing, total energy and time). The second is to be able to report current power consumption and power state. 5.3. MIB Considerations The MIB should be generic as there are a large number of devices yet to come and power states are and will be more so in the future very diverse. Power state categories ("buckets") are on/sleep/off with freely definable power states therein (example ACPI). A fourth basic power state of 'ready' may be more appropriate for some devices, particularly appliances. Reporting should cover both AC and DC power sources (and devices may have more than one power source). However, other types should be provided for, and the type of energy one of the reported values. Standard low-voltage DC (e.g. USB, Power over Ethernet, eMerge) is immediately useful. Eventually, there should be values for wireless power, battery power, and natural gas. A core set of values should be available from any device that implements the Power MIB at all so that an NMS can quickly obtain and aggregate uniform data for all devices. The MIB should be structured so that the smallest possible set of values/information is applicable to a large range of devices, can be implemented efficiently and is extensible to accommodate additional information objects. As an example, many devices will not be battery powered but it should be easy to add battery monitoring to the basic set of energy-related information. It is tempting to add a lot of descriptive information (e.g. on highly specific power states and periodic energy consumption) into the MIB; however, this information will greatly vary across device types. It appears that the best place for such information, if indeed it is needed for the power reporting task, is the NMS and not the MIB itself. 5.4. Power State Monitoring The power state of a device or component typically can only have a small number of discrete values such as, for example, full power, low power, standby, hibernating, off. However, some of these states may have one or more sub-states or state parameters. For example, in low power state, a reduced clock rate may be set to a large number of different values. For the device power state, the following information is considered to be relevant: Nordman & Winter Expires January 6, 2011 [Page 8] Internet-Draft Consider Energy July 2010 o the current state o the time of the last change o the current real power (energy consumption rate) averaged over a short time interval o total energy consumption o energy consumption since the last report or for the last configured time interval Nordman & Winter Expires January 6, 2011 [Page 9] Internet-Draft Consider Energy July 2010 6. Use Cases The following are some different use cases that this facility might be used in. These are not necessarily mutually exclusive. o A data center, with a NMS which is integrated with application functionality, and also manages energy use. o A commercial building, in which the energy reporting is separate from any management of devices, and more as background to help understand building operation (including occupancy) and identify inefficiencies or equipment failures. o A house, which shares some of the commercial building characteristics, but with different management approach and security concerns. o A vehicle, which uses the reporting only for automatic management, not for reporting to the user. Nordman & Winter Expires January 6, 2011 [Page 10] Internet-Draft Consider Energy July 2010 7. Security Considerations None. Nordman & Winter Expires January 6, 2011 [Page 11] Internet-Draft Consider Energy July 2010 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Nordman & Winter Expires January 6, 2011 [Page 12] Internet-Draft Consider Energy July 2010 Authors' Addresses Bruce Nordman Lawrence Berkeley National Laboratory Email: bnordman@lbl.gov Rolf Winter NEC Labs Europe Email: rolf.winter@neclab.eu Nordman & Winter Expires January 6, 2011 [Page 13]