draft-ietf-v6ops-reducing-ra-energy-consumption-02.txt   draft-ietf-v6ops-reducing-ra-energy-consumption-03.txt 
IPv6 Operations A. Yourtchenko IPv6 Operations A. Yourtchenko
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Best Current Practice L. Colitti Intended status: Best Current Practice L. Colitti
Expires: April 4, 2016 Google Expires: May 8, 2016 Google
October 2, 2015 November 5, 2015
Reducing energy consumption of Router Advertisements Reducing energy consumption of Router Advertisements
draft-ietf-v6ops-reducing-ra-energy-consumption-02 draft-ietf-v6ops-reducing-ra-energy-consumption-03
Abstract Abstract
Frequent Router Advertisement messages can severely impact host power Frequent Router Advertisement messages can severely impact host power
consumption. This document recommends operational practices to avoid consumption. This document recommends operational practices to avoid
such impact. such impact.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 4, 2016. This Internet-Draft will expire on May 8, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Problem scenarios . . . . . . . . . . . . . . . . . . . . . . 2 2. Problem scenarios . . . . . . . . . . . . . . . . . . . . . . 2
2.1. Solicited multicast RAs on large networks . . . . . . . . 2 2.1. Solicited multicast RAs on large networks . . . . . . . . 2
2.2. Frequent periodic Router Advertisements . . . . . . . . . 3 2.2. Frequent periodic Router Advertisements . . . . . . . . . 2
3. Consequences . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Consequences . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Router Advertisement frequency . . . . . . . . . . . . . . . 3 4. Router Advertisement frequency . . . . . . . . . . . . . . . 3
5. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 4 5. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Network-side recommendations . . . . . . . . . . . . . . 4 5.1. Network-side recommendations . . . . . . . . . . . . . . 4
5.2. Device-side recommendations . . . . . . . . . . . . . . . 5 5.2. Device-side recommendations . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 5 8. Security Considerations . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 9. Normative References . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
Routing information is communicated to IPv6 hosts by Router Routing information is communicated to IPv6 hosts by Router
Advertisement (RA) messages [RFC4861]. If these messages are too Advertisement (RA) messages [RFC4861]. If these messages are too
frequent, they can severely impact power consumption on battery- frequent, they can severely impact power consumption on battery-
powered hosts. powered hosts.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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Advertisement. In the worst case, if devices are continually joining Advertisement. In the worst case, if devices are continually joining
and leaving the network, and the network is large enough, then all and leaving the network, and the network is large enough, then all
devices on the network will receive solicited Router Advertisements devices on the network will receive solicited Router Advertisements
at the maximum rate specified by section 6.2.6 of [RFC4861], which is at the maximum rate specified by section 6.2.6 of [RFC4861], which is
one every 3 seconds. one every 3 seconds.
2.2. Frequent periodic Router Advertisements 2.2. Frequent periodic Router Advertisements
Some networks send periodic multicast Router Advertisements very Some networks send periodic multicast Router Advertisements very
frequently (e.g., once every few seconds). This may be due to a frequently (e.g., once every few seconds). This may be due to a
desire to ensure that hosts always have access to up-to-date router desire to minimize customer impact of network renumbering events,
information. This has severe impact on battery life. which in some large residential networks occur relatively frequently.
In the presence of hosts that ignore RAs or even all IPv6 packets
when in sleep mode, such networks may see a need to send RAs
frequently in order to avoid leaving devices with non-functional IPv6
configurations for extended periods of time. Unfortunately, this has
severe impact on battery life.
3. Consequences 3. Consequences
Observed reactions to frequent Router Advertisement messages by Observed reactions to frequent Router Advertisement messages by
battery-powered devices include: battery-powered devices include:
o Some hosts simply experience bad battery life on these networks o Some hosts simply experience bad battery life on these networks
and otherwise operate normally. This is frustrating for users of and otherwise operate normally. This is frustrating for users of
these networks. these networks.
o Some hosts react by dropping all Router Advertisement messages o Some hosts react by dropping all Router Advertisement messages
when in power saving mode on any network, e.g., [1]. This causes when in power saving mode on any network, e.g.,
devices to lose connectivity when in power-saving mode, <https://code.google.com/p/android/issues/detail?id=32662>. This
causes devices to lose connectivity when in power-saving mode,
potentially disrupting background network communications, because potentially disrupting background network communications, because
the device is no longer able to send packets or acknowledge the device is no longer able to send packets or acknowledge
received traffic. received traffic.
o Some hosts react by dropping *all* IPv6 packets when in power o Some hosts react by dropping *all* IPv6 packets when in power
saving mode, [2]. This disrupts network communications. saving mode, <http://www.gossamer-threads.com/lists/nsp/
ipv6/54641>. This disrupts network communications.
Compounding the problem, when dealing with devices that drop Router Compounding the problem, when dealing with devices that drop Router
Advertisements when in power saving mode, some network administrators Advertisements when in power saving mode, some network administrators
work around the problem by sending RAs even more frequently. This work around the problem by sending RAs even more frequently. This
causes devices to engage in even more aggressive filtering. causes devices to engage in even more aggressive filtering.
4. Router Advertisement frequency 4. Router Advertisement frequency
The appropriate frequency of periodic RAs depends on how constrained The appropriate frequency of periodic RAs depends on how constrained
the network devices are. the network devices are.
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for a limited period of time (e.g., not more than one minute) for a limited period of time (e.g., not more than one minute)
immediately after a configuration change. immediately after a configuration change.
No protocol changes are required. Responding to Router Solicitations No protocol changes are required. Responding to Router Solicitations
with unicast Router Advertisements is already allowed by section with unicast Router Advertisements is already allowed by section
6.2.6 of [RFC4861], and Router Advertisement intervals are already 6.2.6 of [RFC4861], and Router Advertisement intervals are already
configurable by the administrator to a wide range of values. configurable by the administrator to a wide range of values.
5.2. Device-side recommendations 5.2. Device-side recommendations
1. Mobile devices that intend to maintain IPv6 connectivity while 1. Maintaining IPv6 connectivity requires that hosts be able to
asleep MUST NOT ignore RAs while asleep. receive periodic multicast RAs [RFC4861] Therefore, hosts that
process unicast packets sent while they are asleep MUST also
process multicast RAs sent while they are asleep. Battery-
powered hosts MAY rate-limit identical RAs if they are sent too
frequently.
2. Mobile devices that do not intend to maintain IPv6 connectivity 2. Battery-powered devices that do not intend to maintain IPv6
while asleep SHOULD disconnect from the IPv6 network and SHOULD connectivity while asleep SHOULD either disconnect from the
reconnect to the network (including performing any DNAv6 network, abandoning all IPv6 configuration on that network, or
procedures [RFC6059], sending Router Solicitations and performing perform DNAv6 procedures [RFC6059] when waking up.
Duplicate Address Detection) when waking up.
6. Acknowledgements 6. Acknowledgements
The authors wish to thank Steven Barth, Frank Bulk, David Farmer, Ray The authors wish to thank Steven Barth, Frank Bulk, David Farmer,
Hunter, Erik Kline, Erik Nordmark, Alexandru Petrescu, Libor Polcak, Igor Gashinsky, Ray Hunter, Erik Kline, Erik Nordmark, Alexandru
Mark Smith, and Jinmei Tatuya for feedback and helpful suggestions. Petrescu, Libor Polcak, Mark Smith, Jinmei Tatuya and James Woodyatt
for feedback and helpful suggestions.
7. IANA Considerations 7. IANA Considerations
None. None.
8. Security Considerations 8. Security Considerations
Misconfigured or malicious hosts sending rogue Router Advertisements Misconfigured or malicious hosts sending rogue Router Advertisements
[RFC6104] can also severely impact power consumption on battery- [RFC6104] can also severely impact power consumption on battery-
powered hosts if they send a significant number of such messages. powered hosts if they send a significant number of such messages.
Any IPv6 network where there is potential for misconfigured or Any IPv6 network where there is potential for misconfigured or
malicious hosts should take appropriate countermeasures to mitigate malicious hosts should take appropriate countermeasures to mitigate
the problem. the problem.
9. References 9. Normative References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.
[RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for
Detecting Network Attachment in IPv6", RFC 6059, DOI 10 Detecting Network Attachment in IPv6", RFC 6059, DOI
.17487/RFC6059, November 2010, 10.17487/RFC6059, November 2010,
<http://www.rfc-editor.org/info/rfc6059>. <http://www.rfc-editor.org/info/rfc6059>.
9.2. URIs
[1] https://code.google.com/p/android/issues/detail?id=32662
[2] http://www.gossamer-threads.com/lists/nsp/ipv6/54641
Authors' Addresses Authors' Addresses
Andrew Yourtchenko Andrew Yourtchenko
Cisco Cisco
7a de Kleetlaan 7a de Kleetlaan
Diegem, 1831 Diegem, 1831
Belgium Belgium
Phone: +32 2 704 5494 Phone: +32 2 704 5494
Email: ayourtch@cisco.com Email: ayourtch@cisco.com
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