[Docs] [txt|pdf] [Tracker] [Email] [Nits]

Versions: 00 draft-ietf-opsawg-capwap-extension

Network Working Group                                            Y. Chen
Internet-Draft                                                    D. Liu
Intended status: Informational                                   H. Deng
Expires: August 5, 2013                                     China Mobile
                                                                Lei. Zhu
                                                                  Huawei
                                                                Feb 2013


     CAPWAP Extension for 802.11n and Power/channel Reconfiguration
                 draft-chen-opsawg-capwap-extension-00

Abstract

   CAPWAP binding for 802.11 is specified by RFC5416 and it was based on
   IEEE 802-11.2007 standard.  After RFC5416 was published in 2009,
   there was several new amendent of 802.11 has been published. 802.11n
   is one of those amendent and it has been widely used in real
   deployment.  This document extends the CAPWAP binding for 802.11 to
   support 802.11n.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   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 August 5, 2013.

Copyright Notice

   Copyright (c) 2013 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
   carefully, as they describe your rights and restrictions with respect



Chen, et al.             Expires August 5, 2013                 [Page 1]


Internet-Draft                   capwap                         Feb 2013


   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions used in this document  . . . . . . . . . . . . . .  3
   3.  CAPWAP 802.11n support . . . . . . . . . . . . . . . . . . . .  3
   4.  CAPWAP extension for 802.11n support . . . . . . . . . . . . .  4
   5.  Power and Channel auto reconfiguration . . . . . . . . . . . .  8
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   8.  Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   10. Normative References . . . . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
































Chen, et al.             Expires August 5, 2013                 [Page 2]


Internet-Draft                   capwap                         Feb 2013


1.  Introduction

   IEEE 802.11n standard was published in 2009 and it is an amendment to
   the IEEE 802.11-2007 standard to improve network throughput.  The
   maximum data rate increases to 600Mbit/s physical throughput rate.
   In the physical layer, 802.11n use OFDM and MIMO to achive the high
   throughput. 802.11n use multiple antennas to form antenna array which
   can be dynamically adjusted to imporve the signal strength and extend
   the coverage.

   There are couple of capabilities of 802.11n need to be supported by
   CAPWAP control message such as radio capability, radio configuration
   and station information.


2.  Conventions used in this document

   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.  CAPWAP 802.11n support

   IEEE 802.11n standard was published in 2009 and it is an amendment to
   the IEEE 802.11-2007 standard to improve network throughput.  The
   maximum data rate increases to 600Mbit/s physical throughput rate.
   In the physical layer, 802.11n use OFDM and MIMO to achive the high
   throughput. 802.11n use multiple antennas to form antenna array which
   can be dynamically adjusted to imporve the signal strength and extend
   the coverage.

   802.11n support three modes of channel usage: 20MHz mode, 40Mhz mode
   and mixed mode.802.11n has a new feature called channel binding.  It
   can bind two adjacent 20MHz channel to one 40MHz channel to improve
   the throughput.If using 40Mhz channel configuration there will be
   only one non-overlapping channel in 2.4GHz.  In the large scale
   deployment scenario, operator need to use 20MHz channel configuration
   in 2.4GHz to allow more non-overlapping channels.

   In MAC layer, a new feature of 802.11n is Short Guard Interval(GI).
   802.11a/g use 800ns guard interval between the adjacent information
   symbols.  In 802.11n, the GI can be configured to 400nm under good
   wireless condition.

   Another feature in 802.11 MAC layer is Block ACK. 802.11n can use one
   ACK frame to acknowledge several MPDU receiving event.




Chen, et al.             Expires August 5, 2013                 [Page 3]


Internet-Draft                   capwap                         Feb 2013


   CAPWAP need to be extended to support the above new 802.11n features.
   For example, CAPWAP should allow the access controller to know the
   supported 802.11n features and the access controller should be able
   to configure the differe channel binding modes.  One possible
   solution is to extend the CAPWAP information element for 802.11n.


4.  CAPWAP extension for 802.11n support

   There are couple of capabilities of 802.11n need to be supported by
   CAPWAP control message such as radio capability, radio configuration
   and station information.  This section defines the extension of
   current CAPWAP 802.11 information element to support 802.11n.

   1. 802.11n Radio Capability Information Element.  The information
   element need to be extended to include 802.11n radio capability.
   Below is an example of the 802.11n radio capability information
   element.

































Chen, et al.             Expires August 5, 2013                 [Page 4]


Internet-Draft                   capwap                         Feb 2013


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID         |              Length           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Radio ID   |SupChanl width |   Power Save   |  ShortGi20   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  ShortGi40    | HtDelyBlkack  |  Max Amsdu     |  Max RxFactor|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Min StaSpacing | HiSuppDataRate|   AMPDUBufSize |   HtcSupp    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        20MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11gMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        40MHZ 11aMCS                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   1.   SupChanl width: The supported bandwith mode. 0x01: 20MHz
        bandwidth binding mode. 0x02: 40MHz bandwidth binding mode.





Chen, et al.             Expires August 5, 2013                 [Page 5]


Internet-Draft                   capwap                         Feb 2013


   2.   Power Save: 0x00: Static power saving mode. 0x01: Dynamic power
        saving mode. 0x03: Do not support power saving mode.
   3.   ShortGi20: Whether support short GI. 0x00: Do not support short
        GI. ox01: Support short GI.
   4.   HtDelyBlkack: Whether block Ack support delay mode. 0x00: Do not
        support delay mode. 0x01: Support delay mode.
   5.   Max Amsdu: The maximal AMSDU length. 0: 3839 bytes. 1: 7935
        bytes.
   6.   Max RxFactor: The maximal receiving AMPDU factor.  Default
        value: 3.
   7.   Min StaSpacing: Minimum MPDU Start Spacing.
   8.   HiSuppDataRate: Maximal transmission speed.
   9.   AMPDUBufSize: AMPDU buffer size.
   10.  HtcSupp: Whether the packet have HT header.
   11.  20MHZ 11gMCS: 128 bitmap.If support should be all zero,
        otherwise all one.
   12.  20MHZ 11aMCS: 128 bitmap.If support should be all zero,
        otherwise all one.
   13.  40MHZ 11gMCS: 128 bitmap.If support should be all zero,
        otherwise all one.
   14.  40MHZ 11aMCS: 128 bitmap.If support should be all zero,
        otherwise all one.
   15.  2. 802.11n Raido Configuration TLV.  Following figure is an
        example of 802.11n radio configuration TLV.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID          |              Length           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Radio ID   |   Amsdu Cfg   |   Ampdu Cfg   |  11nOnly Cfg  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | ShortGi Cfg   | BandWidth Cfg |  MaxSupp MCS  |  Max MandMCS  |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    TxAntenna  |    RxAntenna  |         Reserved              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Reserved                            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   1.   A-MSDU CFG: 0x00: Disable 0x01: Enalbe
   2.   A-MPDU CFG: 0x00: Disable 0x01: Enalbe
   3.   11N Only CFG: Whether allow only 11n user access. 0x00: Allow
        non-802.11n user access. 0x01: Do not allow non-802.11n user
        access.
   4.   Short GI CFG: 0x00: Disable 0x01: Enable
   5.   Bandwidth CFG: Bandwidth binding mode. 0x00: 40MHz 0x01: 20MHz





Chen, et al.             Expires August 5, 2013                 [Page 6]


Internet-Draft                   capwap                         Feb 2013


   6.   Max Support MCS: Maximal MCS.
   7.   Max Mandantory MCS: Maximal mandantory MCS.
   8.   TxAntenna: Transmitting antenna configuration.
   9.   RxAntenna: Receiving antenna configuration.
   10.  Each TxAntenna and RxAntenna bit represent one antenna, 1 means
        enable, 0 means disable.

   3. 802.11n Station Information.  Following figure is an example of
   802.11n station information information element.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID          |              Length          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MAC Address                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |SupChanl width |   Power Save  |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  ShortGi20    | ShortGi40     | HtDelyBlkack  |  Max Amsdu    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Max RxFactor | Min StaSpacing|            HiSuppDataRate     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            AMPDUBufSize       |    HtcSupp    |     MCS Set   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   MCS Set                                                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   MCS Set                                                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     MCS Set    |
   +-+-+-+-+-+-+-+-+-

   1.   SupChanl width: Supporting bandwidth mode. 0x01: 20MHz bandwidth
        mode. 0x02: 40MHz bandwidth binding mode.
   2.   Power Save: 0x00: Static power saving mode. 0x01: Dynamic power
        saving mode. 0x03: Do not support power saving mode.
   3.   ShortGi20: Whether support short GI in 20MHz bandwidth mode.
        0x00: Do not support short GI. ox01: Support short GI.
   4.   ShortGi40: Whether support short GI in 40MHz bandwidth mode.
        0x00: Do not support short GI. ox01: Support short GI.
   5.   HtDelyBlkack: Whether block Ack support delay mode. 0x00: Do not
        support delay mode. 0x01: Support delay mode.
   6.   Max Amsdu: The maximal AMSDU length. 0x00: 3839 bytes. 0x01:
        7935 bytes.
   7.   Max RxFactor: The maximal receiving AMPDU factor.
   8.   Min StaSpacing: Minimum MPDU Start Spacing.





Chen, et al.             Expires August 5, 2013                 [Page 7]


Internet-Draft                   capwap                         Feb 2013


   9.   HiSuppDataRate: Maximal transmission speed.
   10.  AMPDUBufSize: AMPDU buffer size.
   11.  HtcSupp: Whether the packet have HT header.
   12.  MCS Set: The MCS bitmap that the station supports.


5.  Power and Channel auto reconfiguration

   Power and channel auto reconfiguration could avoid potential radio
   interference and improve the Wi-Fi performance.  In general, the
   auto-configuration of radio power and channel could occurre at two
   stages: when the AP power on or during the AP running time.

   When the AP is power-on, it is of necessity to configure a proper
   channel to the AP in order to achieve best status of radio links.
   IEEE 802.11 Direct Sequence Control elements or IEEE 802.11 OFDM
   Control element defined in RFC5416 should be carried to offer AP a
   channel at this stage.  Those element should be carried in the
   Configure Status Response message.  If those information element is
   zero, the AP will determine its channel by itself, otherwise the AP
   should be configured according to the provided information element.

   When the AP determines its own channel configuration, it should first
   scan the channel information, then determine which channel it will
   work on and form a channel quality scan report.  The channel quality
   report will be sent to the AC using WTP Event Request message by the
   AP.  The AC can use IEEE 802.11 Direct Sequence Control or IEEE
   802.11 OFDM Control information element carried by the configure
   Update Request message to configure a new channel for the AP.

   IEEE 802.11 Tx Power information element is used by the AC to control
   the transmission power of the AP.  The 802.11 Tx Power information
   element is carried in the Configure Status Response message during
   the power on phase or in the Configure Update Request message during
   the running phase.

   Channel Scan Procedure.

   The Channel Scan Procedure is illustrated by the following figure.












Chen, et al.             Expires August 5, 2013                 [Page 8]


Internet-Draft                   capwap                         Feb 2013


         WTP              Configure Status Req                 AC
         ------------------------------------------------------->
           Configure Status Res(Scan Para TLV, Chl Bind TLV)
         <------------------------------------------------------
       or

       WTP Configure Update Req(Scan Para, Bind TLV)          AC
         <-----------------------------------------------------
                         Configure Update Res
         ----------------------------------------------------->



   The definition of the Scan Para TLV is as follows:



   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID          |              Length          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Radio ID |   AP oper mode                       |   Scan Type  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Reserved                              |
   +---------------------------------------------------------------+
   |          Report Time           |      PrimeChlSrvTime         |
   +---------------------------------------------------------------+
   | On Channel ScanTIme            |   Off Channel ScanTime       |
   +---------------------------------------------------------------+
   |L|D|         Flag               |                              |
   +---------------------------------------------------------------+




   Element ID: TBD; Length:18

   AP oper mode: the work mode of the AP. 0x01:normal mode. 0x02:
   monitor only mode.

   Scan Type: 0x01: active scan; 0x02: passive scan.

   Report Time: Channel quality report time.

   PrimeChlSrvTime: Service time on the working scan channel.  This
   segment is invalid(set to 0) when AP oper mode is set to 2.  The
   maximum value of this segment is 10000, the minimum value of this



Chen, et al.             Expires August 5, 2013                 [Page 9]


Internet-Draft                   capwap                         Feb 2013


   segment is 5000, the default value is 5000.

   On Channle ScanTime: The scan time of the working channel.  When the
   AP oper mode is set to 2, this segment is invalid(set to 0).  The
   maximum value of thi segment is 120, the minimum value of this
   segment is 60, the default value is 60.

   L=1: Open Load Balance Scan.  D=1: Open Rogue AP detection scan.
   Flag: Bitmap, resered for furture use.

   The definition of the Channel Bind TLV is as follows:


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID          |              Length          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Radio ID |                        Flag                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Max Cycles  |      Reserved         |    Channel Count     |
   +---------------------------------------------------------------+
   |                      Scan Channel Set...                      |
   +---------------------------------------------------------------+


   Element ID: TBD.  Length>=12

   Flag: bitmap, reserved.

   Scan Src: the trigger of the scan event. not defined in this version
   of the document. set to 0.

   Device Type: the scope of the scan. not defined is this version of
   the document. set to 0.

   Max Cycles: Scan repeat times. 255 means continuous scan.

   Scan Channel Set: the channle information. the format is as follows:


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Channel ID          |              Flag            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





Chen, et al.             Expires August 5, 2013                [Page 10]


Internet-Draft                   capwap                         Feb 2013


   Channel ID: the channel ID of the channel which will be scanned.

   Flag: bitmap, reserved for future use.

   The channle scan procedure:

   The AP has two work mode: the first one is normal mode.  In this
   mode, the AP can provide service for the STA access and scan the
   channel at the same time.  Whether the AP will scan the channel is
   determined by the Max Cycles segment in the Channle Bind TLV.  When
   this segment is set to 0, the AP will not scan the channle.  If this
   segment is set to 255, the AP will continuous scan the channel.  The
   type of the scan is determined by the Sacn Type segment.  In the
   passive scan type, the AP monitor the airinterface, based on the
   received beacon frame to determine the nearby APs.  In the active
   scan type, the AP will send probe message and receive the probe
   response message.  In the normal scan mode, the AP will use 3
   parameters: PrimeChlSrvTime, OnChannelScanTIme, OffChannelScnTIme.
   The AP will provide access service for the STAs for PrimeChlSrvTime
   duration and then start to scan the channel for On Channel ScnTime
   duration.  Back to the working channel, provide STA access service
   for PrimeChlSrvTime, then leave the working channel, start to scan
   the next channel for Off Channel ScanTime duration.  This process
   will be repeated until all the channel is scanned.

   When the AP work in the scan only mode, there is no difference
   between the working channel and scan channel.  Every channel's scan
   duration will be OffChannelScnTime and the PrimeChlSrvTime and
   OnChannelScanTime is set to 0.

   Scan Report.  THe AP send the scan report to the AC through WTP Event
   Request message.  The information element that used to carry the scan
   report is Channel Scan Report TLV and Neighbor AP Report TLV.  The
   definition of the Channel Scan Report TLV is as follows:


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID          |             Length           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Radio ID     | Report Count    | Channel Scan Report          |
   +---------------------------------------------------------------+


   Element ID: 133; Length: >= 20.

   Report Count: the channle number will be reported.  The definition of



Chen, et al.             Expires August 5, 2013                [Page 11]


Internet-Draft                   capwap                         Feb 2013


   the channel scan report is as follows:


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Channel Number   |      Radar Statistics       | Mean     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Time    | Mean RSSI    | Screen Packet Count             |
   +---------------------------------------------------------------+
   | NeighborCount| Mean Noise   | Interference  | Self Tx Occp    |
   +---------------------------------------------------------------+
   | SelfStaOccp  | Unknown Occp |  CRC Err Cnt  | Decrypt Err Cnt |
   +---------------------------------------------------------------+
   |Phy Err Cnt   | Retrans Cnt  |
   +-----------------------------+


   Channel Number: The channel number.

   Radar Statistics: Whether detect radar signal in this channel. 0x00:
   detect radar signal. 0x01: no radar signal is detected.

   Mean Time: Channel measurement duration.

   Mean RSSI: The signal strength of the scanned channel.

   Screen Packet Count: Received packet number.

   Neighbor Count: The neighbor number of this channel.

   Mean Noise: the average noise on this channel.

   Interference: The interference of the channel.

   Self Tx Occp: The time duration for transmission.

   Unknown Occp: TBD.

   CRC Err Cnt: CRC err packet number.

   Decrypt Err Cnt: Decryption err packet number.

   Phy Err Cnt: Physical err packet number.

   Retrans Cnt: Retransmission packet number.

   The definition of neighbor AP report TLV is as follows:



Chen, et al.             Expires August 5, 2013                [Page 12]


Internet-Draft                   capwap                         Feb 2013


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Element ID          |             Length           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Radio ID     | Reserved        | Number of Neighbor Report    |
   +---------------------------------------------------------------+
   | Neighbor Infor...                                             |
   +---------------------------------------------------------------+


   Element ID: 134; Length:>=16

   The definition of Neighbor info is as follows:


   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            BSSID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            BSSID               |        Channel Number        |
   +---------------------------------------------------------------+
   | 2rd Offset    |  Mean RSSI     | Sta Intf     |    AP Intf    |
   +---------------------------------------------------------------+


   BSSID: The BSSID of this neighbor channel.

   Channel Number: The channel number of this neighbor channel.

   2rd channel offset: TBD.

   Mean RSSI: The average signal strength of the channel.

   Sta Intf: TBD.

   AP Intf: TBD.


6.  Security Considerations

   TBD


7.  IANA Considerations

   None



Chen, et al.             Expires August 5, 2013                [Page 13]


Internet-Draft                   capwap                         Feb 2013


8.  Contributors

   This draft is a joint effort from the following contributors:

   Gang Chen: China Mobile chengang@chinamobile.com

   Naibao Zhou: China Mobile zhounaibao@chinamobile.com

   Chunju Shao: China Mobile shaochunju@chinamobile.com

   Hao Wang: Huawei3Come hwang@h3c.com

   Yakun Liu: AUTELAN liuyk@autelan.com

   Xiaobo Zhang: GBCOM

   Xiaolong Yu: Ruijie Networks

   Song zhao: ZhiDaKang Communications

   Yiwen Mo: ZhongTai Networks


9.  Acknowledgements

   The authors would like to thanks Ronald Bonica and Benoit Claise for
   their usefull suggestions.


10.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4564]  Govindan, S., Cheng, H., Yao, ZH., Zhou, WH., and L. Yang,
              "Objectives for Control and Provisioning of Wireless
              Access Points (CAPWAP)", RFC 4564, July 2006.

   [RFC5415]  Calhoun, P., Montemurro, M., and D. Stanley, "Control And
              Provisioning of Wireless Access Points (CAPWAP) Protocol
              Specification", RFC 5415, March 2009.










Chen, et al.             Expires August 5, 2013                [Page 14]


Internet-Draft                   capwap                         Feb 2013


Authors' Addresses

   Yifan Chen
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: chenyifan@chinamobile.com


   Dapeng Liu
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: liudapeng@chinamobile.com


   Hui Deng
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: denghui@chinamobile.com


   Lei Zhu
   Huawei
   No. 156, Shi-Chuang-Ke-Ji-Shi-Fan-Yuan Beiqing Road, Haidian District
   Beijing 100095
   China

   Email: lei.zhu@huawei.com















Chen, et al.             Expires August 5, 2013                [Page 15]


Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/