--- 1/draft-ietf-v6ops-reducing-ra-energy-consumption-00.txt 2015-09-07 06:14:59.774370123 -0700 +++ 2/draft-ietf-v6ops-reducing-ra-energy-consumption-01.txt 2015-09-07 06:14:59.790370515 -0700 @@ -1,19 +1,19 @@ IPv6 Operations A. Yourtchenko -Internet-Draft cisco +Internet-Draft Cisco Intended status: Best Current Practice L. Colitti -Expires: January 24, 2016 Google - July 23, 2015 +Expires: March 10, 2016 Google + September 7, 2015 Reducing energy consumption of Router Advertisements - draft-ietf-v6ops-reducing-ra-energy-consumption-00 + draft-ietf-v6ops-reducing-ra-energy-consumption-01 Abstract Frequent Router Advertisement messages can severely impact host power consumption. This document recommends operational practices to avoid such impact. Status of This Memo This Internet-Draft is submitted in full conformance with the @@ -22,21 +22,21 @@ 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 24, 2016. + This Internet-Draft will expire on March 10, 2016. Copyright Notice Copyright (c) 2015 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -47,33 +47,36 @@ described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Problem scenarios . . . . . . . . . . . . . . . . . . . . . . 2 2.1. Solicited multicast RAs on large networks . . . . . . . . 2 2.2. Frequent periodic Router Advertisements . . . . . . . . . 2 3. Consequences . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3 + 4.1. Network-side recommendations . . . . . . . . . . . . . . 3 + 4.2. Device-side recommendations . . . . . . . . . . . . . . . 4 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 - 8.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 + 8.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 5 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction Routing information is communicated to IPv6 hosts by Router - Advertisement messages. If these messages are too frequent, they can - severely impact power consumption on battery-powered hosts. + Advertisement (RA) messages [RFC4861]. If these messages are too + frequent, they can severely impact power consumption on battery- + powered hosts. 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]. 2. Problem scenarios 2.1. Solicited multicast RAs on large networks On links with a large number of battery-powered devices, sending @@ -81,23 +84,24 @@ power consumption. This is because every time a device joins the network, all devices on the network receive a multicast Router Advertisement. In the worst case, if devices are continually joining and leaving the network, and the network is large enough, then all devices on the network will receive solicited Router Advertisements at the maximum rate specified by section 6.2.6 of [RFC4861], which is one every 3 seconds. 2.2. Frequent periodic Router Advertisements - Some networks send periodic multicast Router Advertisements (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 information. + Some networks send periodic multicast Router Advertisements very + 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 + information. This has severe impact on battery life. 3. Consequences Observed reactions to frequent Router Advertisement messages by battery-powered devices include: o Some hosts simply experience bad battery life on these networks and otherwise operate normally. This is frustrating for users of these networks. @@ -111,85 +115,105 @@ o Some hosts react by dropping *all* IPv6 packets when in power saving mode, [2]. This disrupts network communications. Compounding the problem, when dealing with devices that drop Router Advertisements when in power saving mode, some network administrators work around the problem by sending RAs even more frequently. This causes devices to engage in even more aggressive filtering. 4. Recommendations +4.1. Network-side recommendations + 1. Router manufacturers SHOULD allow network administrators to - configure the routers to respond to with unicast Router - Advertisements to Router Solicitations if: + configure the routers to respond to Router Solicitations with + unicast Router Advertisements if: * The Router Solicitation's source address is not the unspecified address, and: * The solicitation contains a valid Source Link-Layer Address option. - 2. Networks that serve large numbers (tens or hundreds) of battery- - powered devices SHOULD enable this behaviour. + 2. Administrators of networks that serve large numbers (tens or + hundreds) of battery-powered devices SHOULD enable this + behaviour. 3. Networks that serve battery-powered devices SHOULD NOT send multicast RAs too frequently (e.g., more than one every 5-10 minutes for current battery-powered devices) unless the information in the RA packet has substantially changed. If there is a desire to ensure that hosts pick up configuration changes quickly, those networks MAY send frequent Router Advertisements for a limited period of time (e.g., not more than one minute) immediately after a configuration change. No protocol changes are required. Responding to Router Solicitations with unicast Router Advertisements is already allowed by section 6.2.6 of [RFC4861], and Router Advertisement intervals are already 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 The authors wish to thank Steven Barth, Erik Kline, Erik Nordmark, - Alexandru Petrescu, and Mark Smith for feedback and helpful - suggestions. + Alexandru Petrescu, Mark Smith, and Jinmei Tatuya for feedback and + helpful suggestions. 6. IANA Considerations None. 7. Security Considerations None. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. + [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for + Detecting Network Attachment in IPv6", RFC 6059, DOI 10 + .17487/RFC6059, November 2010, + . + 8.2. URIs [1] https://code.google.com/p/android/issues/detail?id=32662 [2] http://www.gossamer-threads.com/lists/nsp/ipv6/54641 Authors' Addresses Andrew Yourtchenko - cisco + Cisco 7a de Kleetlaan Diegem, 1831 Belgium Phone: +32 2 704 5494 Email: ayourtch@cisco.com + Lorenzo Colitti Google Roppongi 6-10-1 Minato, Tokyo 106-6126 JP Email: lorenzo@google.com