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Versions: (draft-shao-opsawg-capwap-hybridmac) 00 01 02 03 04 05 06 07 08 RFC 7494

Network Working Group                                            C. Shao
Internet-Draft                                                   H. Deng
Intended status: Standards Track                            China Mobile
Expires: August 18, 2014                                   R. Pazhyannur
                                                                   Cisco
                                                                 F. Bari
                                                                    AT&T
                                                                R. Zhang
                                                           China Telecom
                                                           S. Matsushima
                                                        SoftBank Telecom
                                                       February 14, 2014


                   IEEE 802.11 MAC Profile for CAPWAP
                 draft-ietf-opsawg-capwap-hybridmac-02

Abstract

   CAPWAP defines two entities Wireless Transmission Point (WTP) and
   Access Controller (AC).  CAPWAP also defines two MAC (Medium Access
   Control) modes for IEEE 802.11 WTPs: Split and Local MAC . For each
   MAC mode, CAPWAP describes how the MAC functionality is split between
   the WTP and AC.  However, certain functions have not been clearly
   defined.  For example for the Split MAC mode, the IEEE 802.11
   encryption is specified as located in either the AC or the WTP with
   no clear way for the AC to inform the WTP where it should be.  This
   lack of specification leads to interoperability especially when AC
   and WTP come from different vendors.  To solve the problem, this
   specification defines a IEEE 802.11 MAC profile where each profile
   specifies an unambigous division of functionality between the WTP and
   AC.  The IEEE 802.11 MAC profile is used as follows: The WTP informs
   the AC of the supported profiles during the discovery or join process
   and the AC configures the WTP with one of the supported profiles
   while configuring a WLAN.

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



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   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 18, 2014.

Copyright Notice

   Copyright (c) 2014 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
   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   4
   3.  IEEE MAC Profile Descriptions . . . . . . . . . . . . . . . .   4
     3.1.  Split MAC with WTP encryption . . . . . . . . . . . . . .   4
     3.2.  Split MAC with AC encryption  . . . . . . . . . . . . . .   5
     3.3.  IEEE 802.11 MAC Profile  Frame Exchange . . . . . . . . .   6
   4.  MAC Profile Message Element Definitions . . . . . . . . . . .   7
     4.1.  IEEE 802.11 Supported MAC Profiles  . . . . . . . . . . .   7
     4.2.  IEEE 802.11 MAC Profile . . . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The CAPWAP protocol supports two MAC modes of operation: Split and
   Local MAC, as described in [RFC5415], [RFC5416].  However, there are
   MAC functions that have not been clearly defined.  For example IEEE
   802.11 encryption is specified as located in either in the AC or the
   WTP with no clear way to negotiate where it should be located.
   Because different vendors have their own definition of the MAC mode,
   many MAC layer functions are mapped differently to either the WTP or
   the AC by different vendors.  Therefore, depending upon the vendor,



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   the operators in their deployments have to perform different
   configurations based on implementation of the two modes by their
   vendor.  If there is no clear specification then operators will
   experience difficulty in interoperating WTPs and ACs from different
   vendors.

   Figure 1 quoted from [RFC5416], illustrates how the functions are
   processed in different places in the Local MAC and Split MAC mode.
   Specifically, note that in the Split MAC mode the IEEE 802.11
   encryption/decryption is specified as WTP/AC implying that it could
   be at either location.


   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Functions                  | Local MAC | Split MAC |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Distribution Service     |  WTP/AC   |     AC    |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Integration Service      |   WTP     |     AC    |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Beacon Generation        |   WTP     |     WTP   |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Probe Response Generation|   WTP     |     WTP   |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Function    |Power Mgmt               |   WTP     |     WTP   |
   +             |/Packet Buffering        |           |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Fragmentation            |   WTP     |    WTP/AC |
   +             |/Defragmentation         |           |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Assoc/Disassoc/Reassoc   |  WTP/AC   |     AC    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Classifying              |   WTP     |     AC    |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 QoS  |Scheduling               |   WTP     |    WTP/AC |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Queuing                  |   WTP     |    WTP    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.1X/EWTP         |   AC      |    AC     |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 RSN  |RSNA Key Management      |   WTP     |     AC    |
   +  (WPA2)     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.11              |   WTP     |    WTP/AC |
   +             |Encryption/Decryption    |           |           |
   |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 1: Functions in Local MAC and Split MAC




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   To solve this problem, this specification introduces IEEE 802.11 MAC
   profle.  The MAC profile unamabigously specifies where the various
   MAC fucntionality should be located.

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.  IEEE MAC Profile Descriptions

   A IEEE MAC Profile refers to a description of how the MAC
   functionality is split between the WTP and AC shown in Figure 1

3.1.  Split MAC with WTP encryption

   The functional split for the Split MAC with WTP encryption is
   provided in Figure 2.  This profile is similar to the Split MAC
   except that IEEE 802.11 encryption/decryption is at the WTP.  Note
   that fragmentation is always done at the same entity as the
   encryption.  Consequently, in this profile fragmentation/
   defragmentation is also done only at the WTP Note that scheduling
   functionality is denoted as WTP/AC.  As explained in [RFC5416], this
   means that the admission control component of IEEE 802.11 resides on
   the AC, the real-time scheduling and queuing functions are on the
   WTP.
























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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Functions                  | Profile   |
   |                                       |    0      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Distribution Service     |   AC      |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Integration Service      |   AC      |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Beacon Generation        |   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Probe Response Generation|   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Function    |Power Mgmt               |   WTP     |
   +             |/Packet Buffering        |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Fragmentation            |   WTP     |
   +             |/Defragmentation         |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Assoc/Disassoc/Reassoc   |   AC      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Classifying              |   AC      |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 QoS  |Scheduling               |   WTP/AC  |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Queuing                  |   WTP     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.1X/EWTP         |   AC      |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 RSN  |RSNA Key Management      |   AC      |
   +  (WPA2)     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.11              |   WTP     |
   +             |Encryption/Decryption    |           |
   |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

           Figure 2: Functions in Split MAC with WTP Encryption

3.2.  Split MAC with AC encryption

   The functional split for the Split MAC with AC encryption is provided
   in Figure 3.  This profile is similar to the Split MAC except that
   IEEE 802.11 encryption/decryption is done only at the AC.  Since
   fragmentation is always done at the same entity as the encryption, in
   this rofile, AC does fragmentation/defragmentation.








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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Functions                  | Profile   |
   |                                       |    1      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Distribution Service     |   AC      |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Integration Service      |   AC      |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Beacon Generation        |   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Probe Response Generation|   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Function    |Power Mgmt               |   WTP     |
   +             |/Packet Buffering        |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Fragmentation            |   AC      |
   +             |/Defragmentation         |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Assoc/Disassoc/Reassoc   |   AC      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Classifying              |   AC      |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 QoS  |Scheduling               |   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Queuing                  |   WTP     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.1X/EWTP         |   AC      |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 RSN  |RSNA Key Management      |   AC      |
   +  (WPA2)     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.11              |   AC      |
   +             |Encryption/Decryption    |           |
   |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

            Figure 3: Functions in Split MAC with AC encryption

3.3.  IEEE 802.11 MAC Profile Frame Exchange

   An example of message exchange using the the IEEE 802.11 MAC Profile
   message element is shown in Figure 4.  The WTP informs the AC of the
   various MAC profiles it supports.  This happens either in a Discovery
   Request message or the Join Request message.  The AC determines the
   appropriate profile and the configures the WTP with the profile while
   configuring the WLAN.







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       +-+-+-+-+-+-+                             +-+-+-+-+-+-+
       |    WTP    |                             |    AC     |
       +-+-+-+-+-+-+                             +-+-+-+-+-+-+
             |Join Request[Supported IEEE 802.11       |
             |       MAC Profiles   ]                  |
             |---------------------------------------->|
             |                                         |
             |Join Response                            |
             |<----------------------------------------|
             |                                         |
             |IEEE 802.11 WLAN Config. Request [       |
             | IEEE 802.11 Add WLAN,                   |
             | IEEE 802.11 MAC Profile                 |
             |   ]                                     |
             |<----------------------------------------|
             |                                         |
             |IEEE 802.11 WLAN Config. Response        |
             |---------------------------------------->|


          Figure 4: Message Exchange For Negotiating MAC Profile

4.  MAC Profile Message Element Definitions

4.1.  IEEE 802.11 Supported MAC Profiles

   The IEEE 802.11 Supported MAC Profile message element allows the WTP
   to communicate the profiles it supports.  The Discovery Request
   message, Primary Discovery Request message, and Join Request message
   may include one such message element.

           0               1               2               3
           0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0
          +=+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
          | Num_Profiles  |  Profile_1    |   Profile_[2..N]..
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

               Figure 5: IEEE 802.11 Supported MAC Profiles

   o  Type: TBD for IEEE 802.11 Supported MAC Profiles
   o  Num_Profiles >=1: This refers to number of profiles present in
      this messaage element.  There must be at least one profile.
   o  Profile: Each profile is idnentified by a value specified in
      Section 4.2.







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4.2.  IEEE 802.11 MAC Profile

   The IEEE 802.11 MAC Profile message element allows the AC to select a
   profile.  This messsage element may be provided along with the IEEE
   802.11 ADD WLAN message element while configuring a WLAN on the WTP.


           0 1 2 3 4 5 6 7
          +=+-+-+-+-+-+-+-+
          |  Profile      |
          +-+-+-+-+-+-+-+-+

                     Figure 6: IEEE 802.11 MAC Profile

   o  Type: TBD for IEEE 802.11 MAC Profile
   o  Profile: The profile is identified by a value as given below

      *  0: This refers to the Split MAC Profile with WTP encryption
      *  1: This refers to the Split MAC Profile with AC encryption

5.  Security Considerations

   This document doesn't specify security risk difference from
   [RFC5416].  Please refer to the Security section of [RFC5416]

6.  IANA Considerations

   This document requires the following IANA actions.

   o  This specification defines a new message element, IEEE 802.11
      Supported MAC Profiles.  The format of this option is described in
      Section 4.1.  This value needs to be regsitered in the existing
      CAPWAP Message Element Type registry, defined in [RFC5415].
   o  This specification defines a new message element, IEEE 802.11 MAC
      Profile.  The format of this option is described in Section 4.2.
      This value needs to be regsitered in the existing CAPWAP Message
      Element Type registry, defined in [RFC5415].
   o  The Profile field in the IEEE 802.11 Supported MAC Profiles
      message element and IEEE 802.11 MAC Profile message element (see
      Section 4.2) is used to denote the MAC profile.  This document
      defines two values, zero (0) and one (1), and the remaining values
      (2-255) are controlled and maintained by IANA and require an
      Expert Review.








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7.  Contributors

   Yifan Chen chenyifan@chinamobile.com

   Naibao Zhou zhounaibao@chinamobile.com

8.  Acknowledgments

   The authors are grateful for extremely valuable suggestions from
   Dorothy Stanley in developing this specification.

   Guidance from management team: Melinda Shore, Scott Bradner, Chris
   Liljenstolpe, Benoit Claise, Joel Jaeggli, Dan Romascanu are highly
   appreciated.

9.  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.

   [RFC5416]  Calhoun, P., Montemurro, M., and D. Stanley, "Control and
              Provisioning of Wireless Access Points (CAPWAP) Protocol
              Binding for IEEE 802.11", RFC 5416, March 2009.

Authors' Addresses

   Chunju Shao
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: shaochunju@chinamobile.com










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

   Email: denghui@chinamobile.com


   Rajesh S. Pazhyannur
   Cisco
   170 West Tasman Drive
   San Jose, CA 95134
   USA

   Email: rpazhyan@cisco.com


   Farooq Bari
   AT&T
   7277 164th Ave NE
   Redmond WA 98052
   USA

   Email: farooq.bari@att.com


   Rong Zhang
   China Telecom
   No.109 Zhongshandadao avenue
   Guangzhou  510630
   China

   Email: zhangr@gsta.com


   Satoru Matsushima
   SoftBank Telecom
   1-9-1 Higashi-Shinbashi, Munato-ku
   Tokyo
   Japan

   Email: satoru.matsushima@g.softbank.co.jp








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