Networking Working Group JP. Vasseur Internet-Draft Zensys Intended status: Informational JP. Vasseur Expires: January 1, 2008 Cisco Systems, Inc June 30, 2007 Routing Requirement in Low Power and Lossy Networks in Home automation requirements for RL2N-routing draft-brandt-rl2n-home-routing-reqs-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 1, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document presents application specific requirements for Routing in Low power and Loosy Networks (RL2N). The scope of this document is home control and home automation. In a modern home, a high number of wireless devices are used for a wide set of purposes. Examples include lighting control modules, heating control panels, light sensors, temperature sensors, gas/water leak detector, motion Vasseur & Vasseur Expires January 1, 2008 [Page 1] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 detectors, video surveillance, healthcare systems and advanced remote controls. Because such devices only cover a limited radio range, multi-hop routing is often required. Such devices are usually highly constrained in terms of resources such as battery and memory and operate in unstable environments. The aim of this document is to specify the routing requirements for networks comprising such constrained devices in a home network environment. 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]. Table of Contents 1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Home automation applications . . . . . . . . . . . . . . . . . 4 3.1. Turning off the house . . . . . . . . . . . . . . . . . . 5 3.2. Moving a remote control around . . . . . . . . . . . . . . 5 3.3. Adding a new lamp module to the system . . . . . . . . . . 5 3.3.1. Register lamp with portable remote control . . . . . . 5 3.3.2. Register lamp with central light controller; then place lamp . . . . . . . . . . . . . . . . . . . . . . 6 3.3.3. Register lamp outlet and wall switch with light controller . . . . . . . . . . . . . . . . . . . . . . 6 3.3.4. Alarm systems . . . . . . . . . . . . . . . . . . . . 6 3.3.5. Remote video surveillance . . . . . . . . . . . . . . 6 3.3.6. Healthcare . . . . . . . . . . . . . . . . . . . . . . 6 4. Unique requirements of home automation applications . . . . . 7 4.1. Support of groupcast . . . . . . . . . . . . . . . . . . . 7 4.2. Node constrained Routing . . . . . . . . . . . . . . . . . 7 4.3. Support of Mobility . . . . . . . . . . . . . . . . . . . 7 4.4. Quality of Service (QoS) Routing . . . . . . . . . . . . . 8 4.5. Scalability . . . . . . . . . . . . . . . . . . . . . . . 8 4.6. Convergence Time . . . . . . . . . . . . . . . . . . . . . 8 4.7. Delay Tolerant Networks . . . . . . . . . . . . . . . . . 8 4.8. Manageability . . . . . . . . . . . . . . . . . . . . . . 8 5. Traffic pattern . . . . . . . . . . . . . . . . . . . . . . . 9 6. Open issues . . . . . . . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . . 10 Vasseur & Vasseur Expires January 1, 2008 [Page 2] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Intellectual Property and Copyright Statements . . . . . . . . . . 11 Vasseur & Vasseur Expires January 1, 2008 [Page 3] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 1. Terminology L2N: Low power and Lossy Network. RL2N: Routing in Low power and Lossy Networks. 2. Introduction This document presents application specific requirements for routing in low power and lossy networks (RL2N). The scope of this document is home control and home automation. In a modern home, a high number of wireless devices are used for a wide set of purposes. Examples include lighting control modules, heating control panels, light sensors, temperature sensors, gas/water leak detector, motion detectors, video surveillance, healthcare systems and advanced remote controls. Basic home control modules such as wall switches and plug-in modules may be turned into an advanced home automation solution via the use of an IP-enabled application reading wall switches, motion sensors, light sensors, rain sensors, and so on. Because such devices only cover a limited radio range, multi-hop routing is often required. These devices are usually highly constrained in term of resources such as battery and memory and operate in unstable environments. Persons moving around in a house, opening or closing a door or starting a vacuum cleaner affect reception of weak radio signals. Reflection and absorption may cause a reliable connection to turn unreliable for a period of time and then being restored again, thus the term "lossy". Section 3 describes common use cases for home automation applications. Section 4 discusses the routing requirements for networks comprising such constrained devices in a home network environment. These requirements may be overlapping requirements derived from other application-specific requirements documents or as listed in [I-D.culler-rsn-routing-reqs]. 3. Home automation applications Home automation applications represent a special segment of networked wireless devices. To facilitate the requirements discussion in Section 4, this section lists a few typical use cases of home automation applications. New applications are being developed at a high pace and this section does not mean to be exhaustive. Vasseur & Vasseur Expires January 1, 2008 [Page 4] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 3.1. Turning off the house Using the direct analogy to an electronic car key, a house owner may stand at the gate and activate the "leaving home" function from his/ her electronic house key, mobile phone, etc. For the sake of visual impression, all lights should turn off at the same time. At least, it should appear to happen at the same time. A well-known problem in home automation is the "popcorn effect": Lamps are turned on one at a time, at a rate so slow that it is clearly visible. Obviously, this mostly apply to very low bandwidth RF systems. Some existing home automation solutions use a clever mix of a "subnet groupcast" message with no acknowledgement and no forwarding before sending acknowledged singlecast messages to each lighting device. Broadcast packets cannot be used for this since some lights should stay on. Consequently, traditional IP multicast cannot be used for such applications. The light controller forms the groups and decides which light modules should receive "turn-off" or "turn-on" requests. 3.2. Moving a remote control around Advanced multi-function remote control may be used for dimming the light in the dining room while eating, turning up the music while doing the dishes in the kitchen and then, later on, turn lights down and start a DVD in the home theater. The music is stopped at the same time. Reaction must appear to be instant (within a few hundreds of milliseconds) even when the remote control has moved to a new location. Devices that needed routing to be reached before may be accessible directly now and vice versa. 3.3. Adding a new lamp module to the system This apparently simple action may be addressed in a number of ways, depending on philosophy. The main issue is that the small-size, low- cost modules may have no user interface except for a single button. Thus, an automated inclusion process is needed for light controllers to find new modules. 3.3.1. Register lamp with portable remote control A remote control may control all lamps in the house. The new lamp module is powered at its final location. A discovery mechanism (potentially based on a broadcast-based protocol) makes the remote control discover the new module within direct range. The user sets up rules in the remote control for control of the lamp module. The lamp module being powered up at the final location triggers routing update. But because the (portable) remote control goes to sleep just after the last communication, the routers cannot determine the location of the remote control by probing for it. Vasseur & Vasseur Expires January 1, 2008 [Page 5] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 3.3.2. Register lamp with central light controller; then place lamp In this scenario a central light controller controls all lamps in the house. The new lamp module is powered within direct range of the light controller. A discovery (potentially based on a broadcast- based protocol) makes the light controller discover the new module. The user sets up rules in the light controller for control of the lamp module. Then the lamp module is placed at its final location. The lamp module being powered up at the final location causes routers to update routes. 3.3.3. Register lamp outlet and wall switch with light controller In this scenario, a central light controller is still used to controls all lamps in the house. It is practical to mount an outlet and get it registered at the same time. The same applies to wall switches. The wall switch may be out of direct range of the lamp module. At least two scenarios can be envisioned: 3.3.3.1. Installer controller used to set up rules A special portable controller is used to first discover the lamp outlet and the wall switch locally, i.e. within direct reach of their respective locations. Then rules are set up in the light controller for the new lamp outlet and wall switch. The lamp module being powered up at the final location triggers routing updates. 3.3.3.2. Global discovery The lamp outlet and wall switch devices announce themselves to the network. If already armed for an inclusion, routers carry the announcement to the light controller. Then rules are set up in the light controller for the new lamp outlet and wall switch. The lamp module being powered up at the final location triggers routing updates. 3.3.4. Alarm systems This section will be documented in further revision of this document. 3.3.5. Remote video surveillance This section will be documented in further revision of this document. 3.3.6. Healthcare This section will be documented in further revision of this document. Vasseur & Vasseur Expires January 1, 2008 [Page 6] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 4. Unique requirements of home automation applications Home automation applications have a number of specific requirements related to the perceived operation of the system. 4.1. Support of groupcast The routing protocol MUST support multicast routing with various scopes: local subnet, all devices. In other words, the routing protocol MUST provide the ability to route a packet toward a single device, a set of devices or all devices in the house. It may be discussed how to achieve group addressing with IP addressing schemes. Some home automation systems require low-level addressing of a group of nodes in the same subnet without any prior creation of multicast groups, simply carrying a list of recipients in the subnet. Thus the routing protocol MUST support the ability to route a packet destined to a single device, a set of devices or all devices. With IP Multicast, signalling mechanisms are used by a receivers to join a group and the sender does not necessarily know the receivers of the group. What is required is the ability to address a group of receivers known by the sender even if the receivers do not need to know that they have been grouped by the sender (requesting each individual node to join a multicast group will be very impractical): this is referred to as "groupcast" mechanism in this document. 4.2. Node constrained Routing Battery-powered nodes such as movement sensors on garage doors and rain meters may not be able to assist in routing. Depending on the node type, the node never listens at all, listens rarely or makes contact on demand to a pre-configured target node. Attempting to communicate to such nodes may require long time before getting a response. The routing engine MUST be aware of special node properties caused for example by battery conservation. Thus the routing process MUST support node constrained routing. 4.3. Support of Mobility In a residential home environment, although the majority of devices are fixed devices, there is still a variety of mobile devices: for example a remote control used for multiple purposes is likely to move. Another example of mobile devices is wearable healthcare devices. Vasseur & Vasseur Expires January 1, 2008 [Page 7] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 The routing protocol MUST provide mobility with convergence time within a few hundreds of milli-seconds. 4.4. Quality of Service (QoS) Routing Home networks typically hosts a variety of applications such as FTP, HTTP, and so on as well as home automation traffic. It is expected to see in such networks several classes of services. Although is most cases a single topology supporting several classes of services may be sufficient, the support of traffic substantially differing in nature (e.g. Low priority high volume traffic such as email with high priority low volume traffic for alarm detection) may require for the routing protocol to support more than one topologies. RL2N MAY provide the ability to support multi-topology routing. 4.5. Scalability Looking at the number of wall switches and power outlets in a modern house, it seems quite realistic that hundreds low power devices may form a home automation network in a fully populated smart home. Moving towards professional building automation, the number of such devices may be on the order of several thousands. Thus the routing protocol MUST be highly scalable supporting a large number of devices. 4.6. Convergence Time Home automation is clearly an L2N subject to various instability due to signal strength variation. Furthermore, as the number of (battery powered) devices increases, the probability of node failure may also increase. In all cases, response time of the order of a few hundreds of milliseconds are required, implying that the routing protocol MUST converge (provide alternate routes upon link or node failure) within a few hundreds of milliseconds. 4.7. Delay Tolerant Networks TBD. 4.8. Manageability TBD Vasseur & Vasseur Expires January 1, 2008 [Page 8] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 5. Traffic pattern Depending on the philosophy of the home automation system, wall switches may be configured to directly control individual lamps or alternatively, all wall switches send control commands to a central lighting control computer which again sends out control commands to relevant light devices. In a distributed system, the traffic tends to be any-to-many. In a centralized system, it is a mix of one-to- one and one-to-many. 6. Open issues Other items to be addressed in further revisions of this document include: * Mobility and traffic pattern, * Load Balancing (Symmetrical and Asymmetrical), * Security. 7. IANA Considerations This document includes no request to IANA. 8. Security Considerations TBD 9. Acknowledgements 10. References 10.1. Normative References [I-D.ietf-pce-pcep] Roux, J. and J. Vasseur, "Path Computation Element (PCE) communication Protocol (PCEP)", draft-ietf-pce-pcep-07 (work in progress), March 2007. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Vasseur & Vasseur Expires January 1, 2008 [Page 9] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. 10.2. Informative References [I-D.culler-rsn-routing-reqs] Cullerot, D. and J. Vasseur, "Routing Requirements for Sensor Networks", draft-culler-rsn-routing-reqs-00 (work in progress), April 2007. Authors' Addresses A Brandt Zensys Emdrupvej 26 Copenhagen, Denmark DK-2100 Email: abr@zen-sys.com JP Vasseur Cisco Systems, Inc 1414 Massachusetts Avenue Boxborough, MA 01719 USA Email: jpv@cisco.com Vasseur & Vasseur Expires January 1, 2008 [Page 10] Internet-Draft draft-brandt-rl2n-home-routing-reqs-00 June 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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