Network Working Group
Internet Engineering Task Force (IETF)                           C. Shao
Internet-Draft
Request for Comments: 7494                                       H. Deng
Intended status:
Category: Standards Track                                   China Mobile
Expires: June 21, 2015
ISSN: 2070-1721                                            R. Pazhyannur
                                                           Cisco Systems
                                                                 F. Bari
                                                                    AT&T
                                                                R. Zhang
                                                           China Telecom
                                                           S. Matsushima
                                                        SoftBank Telecom
                                                       December 18, 2014
                                                              March 2015

    IEEE 802.11 MAC Medium Access Control (MAC) Profile for CAPWAP
                 draft-ietf-opsawg-capwap-hybridmac-08 Control and
            Provisioning of Wireless Access Points (CAPWAP)

Abstract

   The CAPWAP Control and Provisioning of Wireless Access Points (CAPWAP)
   protocol binding for IEEE 802.11 defines two MAC (Medium Medium Access Control) Control
   (MAC) modes for IEEE 802.11 WTP (Wireless Wireless Transmission
   Point): Points (WTPs):
   Split and Local MAC.  In the Split MAC mode, the partitioning of
   encryption/decryption functions are is not clearly defined.  In the Split
   MAC mode description, IEEE 802.11 encryption is specified as located
   in either the AC (Access Controller) Access Controller (AC) or the WTP, with no clear way
   for the AC to inform the WTP of where the encryption functionality
   should be located.  This leads to interoperability issues, especially
   when the AC and WTP come from different vendors.  To prevent
   interoperability issues, this specification defines an IEEE 802.11
   MAC profile Profile message element in which each profile specifies an
   unambiguous division of encryption functionality between the WTP and
   AC.

Status of This Memo

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

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   This Internet-Draft will expire on June 21, 2015.
   http://www.rfc-editor.org/info/rfc7494.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IEEE MAC Profile Descriptions . . . . . . . . . . . . . . . .   4   5
     2.1.  Split MAC with WTP encryption Encryption . . . . . . . . . . . . . .   4   5
     2.2.  Split MAC with AC encryption Encryption  . . . . . . . . . . . . . .   5   6
     2.3.  IEEE 802.11 MAC Profile Frame Exchange  . . . . . . . . .   6   7
   3.  MAC Profile Message Element Definitions . . . . . . . . . . .   7   8
     3.1.  IEEE 802.11 Supported MAC Profiles  . . . . . . . . . . .   7   8
     3.2.  IEEE 802.11 MAC Profile . . . . . . . . . . . . . . . . .   8   9
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   8   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8   9
   6.  Contributors  References  . . . . . . . . . . . . . . . . . . . . . . . .   9
   7. .  10
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Normative References . .  11
   Contributors  . . . . . . . . . . . . . . . . . .   9 . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9  11

1.  Introduction

   The CAPWAP protocol supports two MAC modes of operation: Split and
   Local MAC, as described in [RFC5415], [RFC5415] and [RFC5416].  However, there
   are MAC functions that have not been clearly defined.  For example example,
   IEEE 802.11 [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 different
   definitions of the MAC mode, many MAC layer MAC-layer functions are mapped
   differently to either the WTP or the AC by different vendors.
   Therefore, depending upon the vendor, 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 interoperability
   issues with WTPs and ACs from different vendors.

   Figure 1 from [RFC5416], [RFC5416] illustrates how some functions are processed
   in different places in the Local MAC and Split MAC mode.
   Specifically, note that in the Split MAC mode mode, the IEEE 802.11
   encryption/decryption is specified as WTP/AC WTP/AC, implying that it could
   be at either location.  This is not an issue with Local MAC because
   encryption is always at the WTP.

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            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 Mgmt/              |   WTP     |     WTP   |
   +             |/Packet             |Packet Buffering         |           |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Fragmentation             |Fragmentation/           |   WTP     |    WTP/AC |
   +             |/Defragmentation             |Defragmentation          |           |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Assoc/Disassoc/Reassoc   |  WTP/AC   |     AC    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Classifying              |   WTP     |     AC    |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 QoS  |Scheduling               |   WTP     |    WTP/AC |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Queuing                  |   WTP     |    WTP    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.1X/EAP          |   AC      |    AC     |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 RSN  |RSNA Key Management      |   AC      |    AC     |
   +  (WPA2)     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.11              |   WTP     |    WTP/AC |
   +             |Encryption/Decryption    |           |           |
   |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Note:
     RSN - Robust Security Network
     RSNA - Robust Security Network Association
     WPA2 - Wi-Fi Protected Access 2

              Figure 1: Functions in Local MAC and Split MAC

   To solve this problem, this specification introduces the IEEE 802.11
   MAC
   profile. Profile.  The IEEE 802.11 MAC profile Profile unambiguously specifies
   where the various MAC functionality functionalities should be located.

2.  IEEE MAC Profile Descriptions

   A IEEE 802.11 MAC Profile refers to a description of how the MAC
   functionality is split between the WTP and AC shown in Figure 1.

2.1.  Split MAC with WTP encryption Encryption

   The functional split for the Split MAC with WTP encryption is
   provided in Figure 2.  This profile is similar to the Split MAC
   description in [RFC5416], 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, AC; the real-time scheduling and queuing
   functions are on the WTP.

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

   Note:
   EAP - Extensible Authentication Protocol

           Figure 2: Functions in Split MAC with WTP Encryption

2.2.  Split MAC with AC encryption Encryption

   The functional split for the Split MAC with AC encryption is provided
   in Figure 3.  This profile is similar to the Split MAC in [RFC5416] [RFC5416],
   except that IEEE 802.11 encryption/decryption is at the AC.  Since
   fragmentation is always done at the same entity as the encryption, in
   this profile, AC does fragmentation/defragmentation.

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Functions                  | Profile   |
   |                                       |    1      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Distribution Service     |   AC      |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Integration Service      |   AC      |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Beacon Generation        |   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Probe Response Generation|   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Function    |Power Mgmt Mgmt/              |   WTP     |
   +             |/Packet             |Packet Buffering         |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Fragmentation             |Fragmentation/           |   AC      |
   +             |/Defragmentation             |Defragmentation          |           |
   |             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Assoc/Disassoc/Reassoc   |   AC      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Classifying              |   AC      |
   +   IEEE      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | 802.11 QoS  |Scheduling               |   WTP     |
   +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |Queuing                  |   WTP     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             |IEEE 802.1X/EAP          |   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

2.3.  IEEE 802.11 MAC Profile Frame Exchange

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

       +-+-+-+-+-+-+                             +-+-+-+-+-+-+
       |    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 for Negotiating MAC Profile Profiles

3.  MAC Profile Message Element Definitions

3.1.  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 1060 for IEEE 802.11 Supported MAC Profiles

   o  Num_Profiles >=1: This refers to the number of profiles present in
      this message element.  There must be at least one profile.

   o  Profile: Each profile is identified by a value specified in
      Section 3.2.

3.2.  IEEE 802.11 MAC Profile

   The IEEE 802.11 MAC Profile message element allows the AC to select a
   profile.  This message 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 1061 for IEEE 802.11 MAC Profile

   o  Profile: The profile is identified by a value as given below

      *  0: This refers to the IEEE 802.11 Split MAC Profile with WTP
         encryption

      *  1: This refers to the IEEE 802.11 Split MAC Profile with AC
         encryption

4.  Security Considerations

   This document does not introduce any new security risks compared to
   [RFC5416].  The negotiation messages between the WTP and AC have
   origin authentication and data integrity.  As a result result, an attacker
   cannot interfere with the messages to force a less secure less-secure mode
   choice.  The security considerations described in [RFC5416] apply
   here as well.

5.  IANA Considerations

   This document requires the

   The following IANA actions: actions have been completed.

   o  This specification defines two new message elements, elements: IEEE 802.11
      Supported MAC Profiles (described in Section 3.1) and the IEEE
      802.11 MAC Profile (described in Section 3.2).  These elements needs to
      be
      have been registered in the existing CAPWAP "CAPWAP Message Element Type Type"
      registry, defined in [RFC5415].  The values for these elements
      needs to be between 1024 and 2047 (see Section 15.7 in [RFC5415]).

              CAPWAP Protocol Message Element                Type Value
              IEEE 802.11 Supported MAC Profiles              TBD1              1060
              IEEE 802.11 MAC Profile                         TBD2                         1061
   o  The IEEE 802.11 Supported MAC Profiles message element and IEEE
      802.11 MAC Profile message element include a Profile Field field (as
      defined in Section 3.2).  The Profile field in the IEEE 802.11
      Supported MAC Profiles denotes the MAC profiles Profiles supported by the
      WTP.  The profile Profile field in the IEEE 802.11 MAC profile Profile denotes the
      MAC
      profile Profile assigned to the WTP.  The namespace for the field is 8
      bits (0-255).  This specification defines two values, values: zero (0) and
      one (1) as described below.  The remaining values (2-255) are
      controlled and maintained by IANA IANA, and require an the registration procedure
      is Expert Review. Review [RFC5226].  IANA needs to create has created a new sub-registry subregistry
      called IEEE "IEEE 802.11 Split MAC Profile and add the new sub-registry to Profile" under the existing registry
      "Control And Provisioning of Wireless Access Points (CAPWAP)
      Parameters".  The registry format is given below.

               Profile                             Type Value  Reference
               Split MAC with WTP encryption       0           RFC 7494
               Split MAC with AC encryption        1           RFC 7494

6.  Contributors

   Yifan Chen chenyifan@chinamobile.com

   Naibao Zhou zhounaibao@chinamobile.com

7.  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.

8.  References

6.1.  Normative References

   [IEEE.802.11]
              IEEE, "IEEE Standard for Information Technology -
              Telecommunications and information exchange between
              systems - Local and metropolitan area networks - Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications", IEEE Std
              802.11-2012, March 2012,
              <http://standards.ieee.org/about/get/802/802.11.html>.

   [RFC5415]  Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley,
              Ed., "Control And Provisioning of Wireless Access Points
              (CAPWAP) Protocol Specification", RFC 5415, March 2009. 2009,
              <http://www.rfc-editor.org/info/rfc5415>.

   [RFC5416]  Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley,
              Ed., "Control and Provisioning of Wireless Access Points
              (CAPWAP) Protocol Binding for IEEE 802.11", RFC 5416,
              March 2009. 2009, <http://www.rfc-editor.org/info/rfc5416>.

6.2.  Informative References

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008, <http://www.rfc-editor.org/info/rfc5226>.

Acknowledgments

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

   Guidance from the management team -- Melinda Shore, Scott Bradner,
   Chris Liljenstolpe, Benoit Claise, Joel Jaeggli, and Dan Romascanu --
   is highly appreciated.

Contributors

   Yifan Chen <chenyifan@chinamobile.com>

   Naibao Zhou <zhounaibao@chinamobile.com>

Authors' Addresses

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

   Email:

   EMail: shaochunju@chinamobile.com

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

   Email:

   EMail: denghui@chinamobile.com

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

   Email:
   United States

   EMail: rpazhyan@cisco.com
   Farooq Bari
   AT&T
   7277 164th Ave NE
   Redmond
   Redmond, WA 98052
   USA

   Email:
   United States

   EMail: farooq.bari@att.com

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

   Email:

   EMail: zhangr@gsta.com

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

   Email:

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