Internet DRAFT - draft-hong-lwig-sleepmode-control

draft-hong-lwig-sleepmode-control







Network Working Group                                            Y. Hong
Internet-Draft                                                      ETRI
Intended status: Informational                                   J. Youn
Expires: May 11, 2014                                     DONG-EUI Univ.
                                                       November 07, 2013


         Sleep node control mechanism for Constrained networks
                  draft-hong-lwig-sleepmode-control-00

Abstract

   This document describes the mechanism of sleep mode control.  The
   router which manages a network can control IPv6 sleepy nodes and
   deliver the packets from/to exterior networks.  The IPv6 router can
   keep the IPv6 sleepy node as sleep state and handle the packets from/
   to the IPv6 sleepy nodes.  Also, this document describes the
   mechanism of sleep mode control using synchronization information.

Status of This Memo

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   This Internet-Draft will expire on May 11, 2014.

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   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Terminology . . . . . . . . . . . . . . . . .   3
   3.  Related Work and Background . . . . . . . . . . . . . . . . .   3
   4.  Sleep mode control mechanism  . . . . . . . . . . . . . . . .   3
     4.1.  Sleep mode request/response . . . . . . . . . . . . . . .   4
     4.2.  Sleep mode advertisement by Router  . . . . . . . . . . .   5
     4.3.  Sleep mode control by using synchronization information .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   In order to minimize the use of the battery of devices which are not
   always connected to a power source, the devices become asleep (sleep
   mode) for a long time and wake up to communicate (active mode) for a
   short time.  To keep the exact time of sleep mode/active mode of the
   devices, the network usually utilizes the synchronization information
   of a Base Station or an Access Point.  Although the devices
   switchover between active mode and sleep mode, the protocol in PHY/
   MAC layer knows the transit time in advance through the
   synchronization information.

   The goals for power management may be different by the conditions of
   device and environment.  The general strategies for power management
   of various conditions are depicted as always-on, always-off, and low-
   power [I-D.arkko-lwig-cellular].  A constrained node, creating
   constrained node networks, may occasionally go into sleep mode
   according to strategies of using power for communication
   [I-D.ietf-lwig-terminology].  In [I-D.ietf-lwig-terminology], a
   device is divided into four classes according to energy limitation of
   a device.  Here, the constrained nodes classed such as class E1 and
   E2 in classes of energy limitation may occasionally go into sleepy
   mode.  Thus, in constrained node networks, there can exist the end-
   to-end communications between a sleep mode node and a non-sleep mode
   node.

   Recently, the power management issues arise in not only PHY/MAC layer
   but also above network layer.  In network/transport/application
   layer, it is assumed that the network devices are always connected



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   and ready to communicate.  But, as various smart object devices
   become connected to the Internet and power management to save battery
   of devices is required.

2.  Conventions and Terminology

   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].

3.  Related Work and Background

   Power saving in wireless networks is mainly accomplished in PHY/MAC
   layer.  The basic idea of power saving in PHY/MAC layer is to
   minimize the time of transmission/receipt.  In IEEE 802.11 WLAN, the
   feature of power saving is Power Save Mode (PSM) that is available
   for nodes existing in an infrastructure based IEEE 802.11 WLAN.  PSM
   is based on a synchronous sleep scheduling policy, in which wireless
   nodes are able to alternate between an active mode and a sleep mode
   [PowerMgmt].

   Recently, the consideration of power saving is moved to network
   layer, too.  In 6lowpan, the Neighbor Discovery operations must
   consider the low-power wireless personal area networks such as IEEE
   802.15.4.  Because the usage of multicast signaling raises severe
   energy consumption, the Neighbor Discovery optimization for 6lowpan
   has limited the usage of multicast signaling [I-D.ietf-6lowpan-nd].

   In application layer, the CoAP has two functions such as proxy and
   cache.  The proxy function in the CoAP can cache and service requests
   for sleepy servers.  Thus, a client sends a CoAP request to a proxy
   on behalf of an origin server of sleep mode and then it respond
   directly to the client through the proxy.  Otherwise if the proxy has
   an invalid representation of the resource in its cache, the proxy has
   to attempt to get the valid resource from an origin server of sleep
   mode.  The attempt may or may not be successful according to the
   state of the origin server [I-D.ietf-core-coap].

4.  Sleep mode control mechanism

   Figure 1 shows the environment where the sleep mode control mechanism
   is used.  In the constrained network, one or more sleepy nodes are
   connected to the router which manages the constrained network and the
   router is connected to external network.







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                           +---------------+
     +---------------+     |               |     +--------------------+
     |+------+  +------+   |               |   +------+  +----------+ |
     ||Sleepy|--|Router|---+               +---|Router|--|Non-Sleepy| |
     || node |  +------+   |               |   +------+  |  node    | |
     |+------+   |   |     |               |     |   |   +----------+ |
     |           |   |     |   Internet    |     |   |                |
     |+------+   |   |     |               |     |   |   +----------+ |
     ||Sleepy|---+   |     |               |     |   +---|Non-Sleepy| |
     || node |       |     |               |     |       |   node   | |
     |+------+       |     |               |     |       +----------+ |
     +---------------+     |               |     +--------------------+
        Constrained        +---------------+           General
        networks                                       networks


     Figure 1: Environment where sleep mode control mechanism is used

4.1.  Sleep mode request/response

   If a sleepy host wants to enter to sleep mode, it sends a request
   message to the router.  The router which receives the request message
   records the status of the sleepy node as sleep mode.  And then, the
   router sends a response message to confirm the request.  If the
   sleepy node receives the request message, it enters sleep mode.  The
   router which manages the constrained network sends the status of the
   sleepy node to the corresponding nodes if the sleepy node is
   communicating.  So, the corresponding nodes immediately know the
   status of the sleepy node.  Figure 2 depicts this procedure.


            Constrained netwokr                General network
       +-------------------------+         +----------------------------+
       | +------+           +------+     +------+        +------------+ |
       | |Sleepy|-----------|Router|     |Router|--------| Non-Sleepy | |
       | | node |           |      |-----|      |        |    node    | |
       | +------+           +------+     +------+        +------------+ |
       +-------------------------+         +----------------------------+
           |                    |            |                    |
           |  Sleep mode REQ    |            |                    |
           |------------------->|            |                    |
           |                    |            |                    |
           |         Host info -> Sleep mode |                    |
           |                    |            |                    |
           |  Sleep mode ACK    |            |                    |
           |<-------------------|            |                    |
           |                    |            |                    |
         Sleep mode             |            |                    |



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           |                    |  Sleeping  |                    |
           |                    |Host Notice |                    |
           |                    |----------->|                    |
           |                    |            |    Sleeping Host   |
           |                    |            |        Notice      |
           |                    |            |------------------->|
           |                    |            |                    |



            Figure 2: Procedure of sleep mode request/response

4.2.  Sleep mode advertisement by Router

   If some conditions are satisfied or events are triggered, a router in
   a constrained network sends a sleep mode advertisement message to
   sleepy nodes.  The sleep mode advertisement message includes the
   start time and finish time of sleep mode.  If sleepy nodes receive
   the advertisement message, they enter sleep mode.  Some cases, the
   sleepy nodes may responds to the advertisement message.  After the
   router change the status of sleepy node to sleep mode and deliver the
   status information of sleepy nodes to corresponding nodes if there
   are corresponding nodes that are communicating to the sleepy nodes.
   So, the corresponding nodes immediately know the status of the sleepy
   nodes.  Figure 3 depicts this procedure.



            Constrained netwokr                General network
       +-------------------------+         +----------------------------+
       | +------+           +------+     +------+        +------------+ |
       | |Sleepy|-----------|Router|     |Router|--------| Non-Sleepy | |
       | | node |           |      |-----|      |        |    node    | |
       | +------+           +------+     +------+        +------------+ |
       +-------------------------+         +----------------------------+
           |                    |            |                    |
           |   Sleep mode Adv.  |            |                    |
           |<-------------------|            |                    |
           |                    |            |                    |
           |  (Sleep mode ACK)  |            |                    |
           |------------------->|            |                    |
           |                    |            |                    |
         Sleep mode             |            |                    |
           |                    |            |                    |
           |         Host info -> Sleep mode |                    |
           |                    |            |                    |
           |                    |  Sleeping  |                    |
           |                    |Host Notice |                    |



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           |                    |----------->|                    |
           |                    |            |    Sleeping Host   |
           |                    |            |        Notice      |
           |                    |            |------------------->|
           |                    |            |                    |



              Figure 3: Procedure of sleep mode advertisement

   If corresponding nodes sends packets to sleepy nodes, the router
   which manages a constrained network retrieves sleeping node list.  If
   the target node is not included in the sleeping node list, the router
   handles the packets as normal process.  If the target node is
   included in the sleeping node list, the router responds to the
   corresponding nodes and informs that the target node is in sleep
   mode.  Figure 4 depicts this procedure.




            Constrained netwokr                General network
       +-------------------------+         +----------------------------+
       | +------+           +------+     +------+        +------------+ |
       | |Sleepy|-----------|Router|     |Router|--------| Non-Sleepy | |
       | | node |           |      |-----|      |        |    node    | |
       | +------+           +------+     +------+        +------------+ |
       +-------------------------+         +----------------------------+
           |                    |            |                    |
           |                    |            |      Pakcet to     |
           |                    |            |     Sleepy node    |
           |                    |            |<-------------------|
           |                    | Packet to  |                    |
           |                    |Sleepy node |                    |
           |                    |<-----------|                    |
           |     Retrieve Sleeping node list |                    |
           |                    |            |                    |
           |  (if in the list)  |            |                    |
           |      Packet to     |            |                    |
           |     Sleepy node    |            |                    |
           |<-------------------|  (if not)  |                    |
           |                    |  Sleeping  |                    |
           |                    |Host Notice |                    |
           |                    |----------->|                    |
           |                    |            |    Sleeping Host   |
           |                    |            |        Notice      |
           |                    |            |------------------->|
           |                    |            |                    |



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   Figure 4: Procedure of the handling of packets from external network

4.3.  Sleep mode control by using synchronization information

   Generally, Base station or Access Point is used to synchronize the
   network entities.  By using the synchronization information, the
   network keeps the exact time of sleep mode/active mode of the network
   entities.  This synchronization information can be also used to
   provide sleep mode control.  Figure 5 shows the case where
   synchronization information is used to provide sleep mode control.
   In Figure 5, the base station offers the synchronization information
   and this synchronization information is delivered to a router by
   using Layer 2 or Layer 3 message or cross-layer mechanism.  After the
   router receives the synchronization information, it knows the sleep
   mode status of sleepy nodes.  If there are corresponding nodes that
   are communicating to the sleepy nodes, the router delivers the status
   information of sleepy nodes to the corresponding nodes.


         Constrained netwokr                        General network
       +--------------------+                  +--------------------------+
       | +------+      +------+   +-------+  +------+      +------------+ |
       | |Sleepy|------|Router|   |  BS   |  |Router|------| Non-Sleepy | |
       | | node |      |      |---| or AP |--|      |      |    node    | |
       | +------+      +------+   +-------+  +------+      +------------+ |
       +--------------------+                  +--------------------------+
           |              |           |          |                  |
           |              |Sync. Info.|          |                  |
           |              |<----------|          |                  |
           | Sync. Info.  |           |          |                  |
           |<-------------|           |          |                  |
           |              |           |          |                  |
           |              | Sleeping  |          |                  |
           |              |Host Notice|          |                  |
           |              |---------->|--------->|                  |
           |              |           |          |  Sleeping Host   |
           |              |           |          |      Notice      |
           |              |           |          |----------------->|
           |              |           |          |                  |


    Figure 5: Procedure of sleep mode control by using synchronization
                                information

5.  Security Considerations

   TBD.




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6.  IANA Considerations

   TBD

7.  References

7.1.  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.

7.2.  Informative References

   [I-D.arkko-lwig-cellular]
              Arkko, J., Eriksson, A., and A. Keranen, "Building Power-
              Efficient CoAP Devices for Cellular Networks", ID draft-
              arkko-lwig-cellular-00, February 2013.

   [I-D.ietf-6lowpan-nd]
              Shelby, Z., Chakrabartiy, S., and E. Nordmark, "Neighbor
              Discovery Optimization for Low Power and Lossy Networks
              (6LoWPAN)", ID draft-ietf-6lowpan-nd-21, August 2012.

   [I-D.ietf-core-coap]
              Shelby, Z., Hartke, K., and C. Bormann, "Constrained
              Application Protocol (CoAP)", ID draft-ietf-core-coap-18,
              June 2013.

   [I-D.ietf-lwig-terminology]
              Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained Node Networks", ID draft-ietf-lwig-
              terminology-05, July 2013.

   [PowerMgmt]
              Klues, K., "Power Management in Wireless Networks",
              Report, for Advanced Topics in Networking: Wireless and
              Mobile Networking by R. Jain, Wash. Univ. in St. Louis, ,
              2006.









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Authors' Addresses

   Yong-Geun Hong
   ETRI
   218 Gajeong-ro Yuseung-Gu
   Daejeon  305-700
   Korea

   Phone: +82 42 860 6557
   Email: yghong@etri.re.kr


   JooSang Youn
   DONG-EUI Univ.
   Busan
   Korea

   Phone: +82 51 890 1993
   Email: joosang.youn@gmail.com
































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