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Requirements for Power Aware Network
draft-dong-panet-requirement-00

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Document Type Active Internet-Draft (individual)
Authors Jie Dong , Mingui Zhang , Beichuan Zhang , Mohamed Boucadair
Last updated 2012-10-15
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draft-dong-panet-requirement-00
Network Working Group                                            J. Dong
Internet-Draft                                                  M. Zhang
Intended status: Informational                       Huawei Technologies
Expires: April 18, 2013                                         B. Zhang
                                               The University of Arizona
                                                            M. Boucadair
                                                          France Telecom
                                                        October 15, 2012

                  Requirements for Power Aware Network
                    draft-dong-panet-requirement-00

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 [RFC2119].

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 April 18, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the

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   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  . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7

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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-greennet].

   While energy consumption has become an important issue, network
   operators are very cautious about energy conservation solutions due
   to the concerns about their potential impacts on the network
   performance and resiliency.

   This document presents a set of requirements for building a power
   aware network while meeting operaters' 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:

   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.

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   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.

   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.

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   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
      (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.

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   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

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

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-09 (work in progress),
              October 2012.

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   [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-00 (work in progress), July 2012.

   [I-D.zhang-greennet]
              Zhang, B., Shi, J., Dong, J., and M. Zhang, "Power-aware
              Routing and Traffic Engineering: Requirements, Approaches,
              and Issues", draft-zhang-greennet-00 (work in progress),
              July 2012.

Authors' Addresses

   Jie Dong
   Huawei Technologies
   Beijing  100095
   China

   Email: jie.dong@huawei.com

   Mingui Zhang
   Huawei Technologies
   Beijing  100095
   China

   Email: zhangmingui@huawei.com

   Beichuan Zhang
   The University of Arizona
   USA

   Email: bzhang@cs.arizona.edu

   Mohamed Boucadair
   France Telecom
   France

   Email: mohamed.boucadair@orange.com

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