draft-ietf-v6ops-reducing-ra-energy-consumption-00.txt   draft-ietf-v6ops-reducing-ra-energy-consumption-01.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: January 24, 2016 Google Expires: March 10, 2016 Google
July 23, 2015 September 7, 2015
Reducing energy consumption of Router Advertisements Reducing energy consumption of Router Advertisements
draft-ietf-v6ops-reducing-ra-energy-consumption-00 draft-ietf-v6ops-reducing-ra-energy-consumption-01
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 January 24, 2016. This Internet-Draft will expire on March 10, 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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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 . . . . . . . . . 2 2.2. Frequent periodic Router Advertisements . . . . . . . . . 2
3. Consequences . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Consequences . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3 4. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3
4.1. Network-side recommendations . . . . . . . . . . . . . . 3
4.2. Device-side recommendations . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4 8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 4 8.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
Routing information is communicated to IPv6 hosts by Router Routing information is communicated to IPv6 hosts by Router
Advertisement messages. If these messages are too frequent, they can Advertisement (RA) messages [RFC4861]. If these messages are too
severely impact power consumption on battery-powered hosts. frequent, they can severely impact power consumption on battery-
powered hosts.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Problem scenarios 2. Problem scenarios
2.1. Solicited multicast RAs on large networks 2.1. Solicited multicast RAs on large networks
On links with a large number of battery-powered devices, sending On links with a large number of battery-powered devices, sending
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power consumption. This is because every time a device joins the power consumption. This is because every time a device joins the
network, all devices on the network receive a multicast Router network, all devices on the network receive a multicast Router
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 (e.g., Some networks send periodic multicast Router Advertisements very
once every few seconds). This may be due to a desire to ensure that frequently (e.g., once every few seconds). This may be due to a
hosts always have access to up-to-date router information. desire to ensure that hosts always have access to up-to-date router
information. 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.
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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, [2]. 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. Recommendations 4. Recommendations
4.1. Network-side recommendations
1. Router manufacturers SHOULD allow network administrators to 1. Router manufacturers SHOULD allow network administrators to
configure the routers to respond to with unicast Router configure the routers to respond to Router Solicitations with
Advertisements to Router Solicitations if: unicast Router Advertisements if:
* The Router Solicitation's source address is not the * The Router Solicitation's source address is not the
unspecified address, and: unspecified address, and:
* The solicitation contains a valid Source Link-Layer Address * The solicitation contains a valid Source Link-Layer Address
option. option.
2. Networks that serve large numbers (tens or hundreds) of battery- 2. Administrators of networks that serve large numbers (tens or
powered devices SHOULD enable this behaviour. hundreds) of battery-powered devices SHOULD enable this
behaviour.
3. Networks that serve battery-powered devices SHOULD NOT send 3. Networks that serve battery-powered devices SHOULD NOT send
multicast RAs too frequently (e.g., more than one every 5-10 multicast RAs too frequently (e.g., more than one every 5-10
minutes for current battery-powered devices) unless the minutes for current battery-powered devices) unless the
information in the RA packet has substantially changed. If there information in the RA packet has substantially changed. If there
is a desire to ensure that hosts pick up configuration changes is a desire to ensure that hosts pick up configuration changes
quickly, those networks MAY send frequent Router Advertisements quickly, those networks MAY send frequent Router Advertisements
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.
4.2. Device-side recommendations
1. Mobile devices that intend to maintain IPv6 connectivity while
asleep MUST NOT ignore RAs while asleep.
2. Mobile devices that do not intend to maintain IPv6 connectivity
while asleep SHOULD disconnect from the IPv6 network and SHOULD
reconnect to the network (including performing any DNAv6
procedures [RFC6059], sending Router Solicitations and performing
Duplicate Address Detection) when waking up.
5. Acknowledgements 5. Acknowledgements
The authors wish to thank Steven Barth, Erik Kline, Erik Nordmark, The authors wish to thank Steven Barth, Erik Kline, Erik Nordmark,
Alexandru Petrescu, and Mark Smith for feedback and helpful Alexandru Petrescu, Mark Smith, and Jinmei Tatuya for feedback and
suggestions. helpful suggestions.
6. IANA Considerations 6. IANA Considerations
None. None.
7. Security Considerations 7. Security Considerations
None. None.
8. References 8. References
8.1. Normative References 8.1. 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, March 1997.
[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. September 2007.
[RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for
Detecting Network Attachment in IPv6", RFC 6059, DOI 10
.17487/RFC6059, November 2010,
<http://www.rfc-editor.org/info/rfc6059>.
8.2. URIs 8.2. URIs
[1] https://code.google.com/p/android/issues/detail?id=32662 [1] https://code.google.com/p/android/issues/detail?id=32662
[2] http://www.gossamer-threads.com/lists/nsp/ipv6/54641 [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
Lorenzo Colitti Lorenzo Colitti
Google Google
Roppongi 6-10-1 Roppongi 6-10-1
Minato, Tokyo 106-6126 Minato, Tokyo 106-6126
JP JP
Email: lorenzo@google.com Email: lorenzo@google.com
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