Requirements for Power Aware Network
Author(s): Beichuan Zhang, Jie Dong, Mingui Zhang, Mohamed Boucadair
Energy consumption of networks is rising fast, which results in the increase of network operational costs. There are emerging demands from operators for power-aware networking (PANET) which could adaptively reduce the network energy consumption when possible. This document...
Network Working Group J. Dong Internet-Draft M. Zhang Intended status: Informational Huawei Technologies Expires: August 29, 2013 B. Zhang The University of Arizona M. Boucadair France Telecom February 25, 2013 Requirements for Power Aware Network draft-dong-panet-requirement-01 Abstract Energy consumption of networks is rising fast, which results in the increase of network operational costs. There are emerging demands from operators for power-aware networking (PANET) which could adaptively reduce the network energy consumption when possible. This document presents the requirements which should be considered in building a power aware network. Requirements Language 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 RFC 2119 [RFC 2119]. 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 August 29, 2013. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the Dong, et al. Expires August 29, 2013 [Page 1] Internet-Draft PANET Requirement February 2013 document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements on Network Elements . . . . . . . . . . . . . . . 3 3. Requirements on Network as a Whole System . . . . . . . . . . . 4 4. Requirements on Control Plane . . . . . . . . . . . . . . . . . 5 5. Requirements on Management Plane . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 9.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Dong, et al. Expires August 29, 2013 [Page 2] Internet-Draft PANET Requirement February 2013 1. Introduction With the increase of network services and exponential growth of traffic volume, the network operators are expanding their infrastructures with more high-capacity, full-featured network devices, which also leads to the increase of network energy consumption. Besides, today's service provider networks are mostly designed for high performance and reliability, without the consideration of energy efficiency. These networks usually have redundant routers and links, over-provisioned link capacity, and multiple paths for load-balancing, which make the networks far from energy efficient. As energy price continues to rise, the increasing network energy consumption becomes a significant portion of the network operational costs. The energy consumption problem in service provider networks is detailed in [I-D.zhang-panet-problem-statement]. Some use cases of reducing network energy consumption are described in [I-D.zhang-panet-use-cases]. While energy consumption has become an important issue, network operators are very cautious about energy conservation solutions due to the concerns about the potential impacts on the network performance and resiliency. This document presents a set of requirements for building a Power Aware NETwork (PANET) while meeting operators' requirements on performance and resiliency. 2. Requirements on Network Elements Today's network elements are mostly designed for high throughput and availability. With the increase of throughput capacity, energy consumption of network element is also rising accordingly. Typically when a network element is turned on, the base energy consumption is high, and the energy consumption does not vary a lot from idle state to fully loaded state. Since in most time the network elements in the network would not work in the full loaded state, if the energy consumption of network elements could be proportional to the carried traffic load, energy conservation could be achieved. While there has been a lot of efforts aiming at making the energy consumption proportional, it is not that easy for the network elements getting to this stage in the near term. In practical, for near term energy saving, the network elements should meet the following requirements: Dong, et al. Expires August 29, 2013 [Page 3] Internet-Draft PANET Requirement February 2013 o Network elements should support a set of energy saving modes (e.g. sleeping modes, etc. defined in IETF EMAN working group). The energy consumption under energy saving modes should be much lower than that under the normal mode. o Network elements should support the transition between different energy modes within acceptable time period, e.g. subsecond. o The transition between different energy modes SHOULD not cost a lot of energy, otherwise there will not be much benefit to transit to energy saving mode. o Network elements should support the report of energy consumption and state information. 3. Requirements on Network as a Whole System While energy awareness of individual network elements is fundamental, currently there are many limits in reducing the energy consumption at device level. Besides, different from terminal devices like PC and cell phones, individual network elements usually cannot be shut down arbitrarily as this may affect the services carried in the network. Thus mechanisms which can reduce the energy consumption of the network as a whole should be considered. Most of the existing networks are over-provisioned for better performance, which means they are not energy efficient by default. In order to save energy, the network as a whole should be power aware, therefore it can make decisions to save energy. Since in most time the network would not carry the peak traffic volume, which means the network could coordinate the network elements to create opportunity for some of the network elements to enter energy saving modes. Meanwhile, reducing energy consumption of the network should not undermine the performance of services carried by the network. Thus for energy saving, the network should meet the following requirements: o The network should try to keep all the active network elements with a reasonable high utilization, network elements with low utilization should be tried to put into energy saving modes. For example, the network elements with low utilization may be put into some low rate mode to reduce energy consumption, or the traffic carried by these network elements may be migrated to other paths such that these network elements could be put into sleeping mode. Dong, et al. Expires August 29, 2013 [Page 4] Internet-Draft PANET Requirement February 2013 o The network should retain enough network availability and resiliency against node and/or link failures. In other words, the redundancy of the network should be kept at a reasonable level, e.g. 2-connected. o Energy saving of the network should not induce increase of latency nor induce traffic loss which exceed the tolerance of the services in the network. QoS metrics such as end-to-end delay, loss and jitter should be kept at a desired level. o The network should reserve enough spare capacity or be able to react quickly to absorb traffic spikes in order to minimize packet losses due to congestions. o The network stability should be preserved. Particularly, traffic oscillation should be avoided. o Energy saving should not conflict with other policies (e.g. performance at the highest priority) in the network. 4. Requirements on Control Plane Most of the existing network control protocols do not take energy efficiency into consideration, and some of them may not work properly when some of the network elements in the network are in energy saving modes. For example, when a network link is put into sleeping mode, the protocols run on this link may be impacted. For energy saving of the whole network, control plane should meet the following requirements: o Control plane should be able to work properly when some of the network elements are in energy saving mode. o Control plane should support the advertisement of energy saving related information (e.g. current energy saving mode) of network elements in the network. o Control plane should be able to coordinate the energy saving operations of network elements to achieve the overall network energy saving. o Control plane should be able to maximize the opportunity for network elements to enter the energy saving modes. o Control plane should be aware of the network elements in energy saving modes, and should be able to calculate available paths Dong, et al. Expires August 29, 2013 [Page 5] Internet-Draft PANET Requirement February 2013 (which do not traverse the network elements in sleeping mode). o Control plane should be able to calculate the path set for services carried by the network in a way that the whole network is energy efficient. Some considerations on control plane when using energy saving mechanism are also specified in [I-D.retana-rtgwg-eacp]. 5. Requirements on Management Plane Management plane would also be necessary for building a power aware network. IETF EMAN working group is working on the requirements [I-D.ietf-eman-requirements]and mechanisms for energy management. Such management requirements include identification of energy-managed devices and their components, monitoring of a series of power states and power properties. It may further includes controlling of the power supply and power states of the managed devices. 6. IANA Considerations This document makes no request of IANA. Note to RFC Editor: this section may be removed on publication as an RFC. 7. Security Considerations TBD 8. Acknowledgements TBD 9. References 9.1. Normative References [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Dong, et al. Expires August 29, 2013 [Page 6] Internet-Draft PANET Requirement February 2013 9.2. Informative References [I-D.ietf-eman-requirements] Quittek, J., Chandramouli, M., Winter, R., Dietz, T., and B. Claise, "Requirements for Energy Management", draft-ietf-eman-requirements-11 (work in progress), January 2013. [I-D.retana-rtgwg-eacp] Retana, A., White, R., and M. Paul, "A Framework and Requirements for Energy Aware Control Planes", draft-retana-rtgwg-eacp-01 (work in progress), February 2013. [I-D.zhang-panet-problem-statement] Zhang, B., Shi, J., Dong, J., Zhang, M., and M. Boucadair, "Power-Aware Networks (PANET): Problem Statement", draft-zhang-panet-problem-statement-01 (work in progress), October 2012. [I-D.zhang-panet-use-cases] Zhang, M., Dong, J., Zhang, B., and B. Khargharia, "Use Cases for Power-Aware Networks", draft-zhang-panet-use-cases-02 (work in progress), February 2013. Authors' Addresses Jie Dong Huawei Technologies Beijing 100095 China Email: email@example.com Mingui Zhang Huawei Technologies Beijing 100095 China Email: firstname.lastname@example.org Dong, et al. Expires August 29, 2013 [Page 7] Internet-Draft PANET Requirement February 2013 Beichuan Zhang The University of Arizona USA Email: email@example.com Mohamed Boucadair France Telecom France Email: firstname.lastname@example.org Dong, et al. Expires August 29, 2013 [Page 8]