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RFC 7561

Informational
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Mapping Quality of Service (QoS) Procedures of Proxy Mobile IPv6 (PMIPv6) and WLAN

 


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Internet Engineering Task Force (IETF)                 J. Kaippallimalil
Request for Comments: 7561                                        Huawei
Category: Informational                                    R. Pazhyannur
ISSN: 2070-1721                                                    Cisco
                                                               P. Yegani
                                                                 Juniper
                                                               June 2015


              Mapping Quality of Service (QoS) Procedures
                 of Proxy Mobile IPv6 (PMIPv6) and WLAN

Abstract

   This document provides guidelines for achieving end-to-end Quality of
   Service (QoS) in a Proxy Mobile IPv6 (PMIPv6) domain where the access
   network is based on IEEE 802.11.  RFC 7222 describes QoS negotiation
   between a Mobile Access Gateway (MAG) and Local Mobility Anchor (LMA)
   in a PMIPv6 mobility domain.  The negotiated QoS parameters can be
   used for QoS policing and marking of packets to enforce QoS
   differentiation on the path between the MAG and LMA.  IEEE 802.11 and
   Wi-Fi Multimedia - Admission Control (WMM-AC) describe methods for
   QoS negotiation between a Wi-Fi Station (MN in PMIPv6 terminology)
   and an Access Point.  This document provides a mapping between the
   above two sets of QoS procedures and the associated QoS parameters.
   This document is intended to be used as a companion document to RFC
   7222 to enable implementation of end-to-end QoS.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7561.

Page 2 
Copyright Notice

   Copyright (c) 2015 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  Overview of IEEE 802.11 QoS . . . . . . . . . . . . . . . . .   7
   3.  Mapping QoS Procedures between IEEE 802.11 and PMIPv6 . . . .   7
     3.1.  MN-Initiated QoS Service Request  . . . . . . . . . . . .   8
       3.1.1.  MN-Initiated QoS Reservation Request  . . . . . . . .   8
       3.1.2.  MN-Initiated QoS De-allocation Request  . . . . . . .  11
     3.2.  LMA-Initiated QoS Service Request . . . . . . . . . . . .  12
       3.2.1.  LMA-Initiated QoS Reservation Request . . . . . . . .  12
       3.2.2.  Discussion on QoS Request Handling with IEEE 802.11aa  13
       3.2.3.  LMA-Initiated QoS De-allocation Request . . . . . . .  14
   4.  Mapping between IEEE 802.11 QoS and PMIPv6 QoS Parameters . .  15
     4.1.  Connection Parameters . . . . . . . . . . . . . . . . . .  15
     4.2.  QoS Class . . . . . . . . . . . . . . . . . . . . . . . .  16
     4.3.  Bandwidth . . . . . . . . . . . . . . . . . . . . . . . .  17
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  19
   Appendix A.  LMA-Initiated QoS Service Flow with IEEE 802.11aa  .  21
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  23
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23

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1.  Introduction

   PMIPv6 QoS [1] describes an access-network-independent way to
   negotiate Quality of Service (QoS) for Proxy Mobile IPv6 (PMIPv6)
   mobility sessions.  IEEE 802.11, Wi-Fi Multimedia (WMM), and Wi-Fi
   Multimedia - Admission Control (WMM-AC) describe ways to provide QoS
   for Wi-Fi traffic between the Wi-Fi Station (STA) and Access Point
   (AP).  This document describes how QoS can be implemented in a
   network where the access network is based on IEEE 802.11 (Wi-Fi).  It
   requires a mapping between QoS procedures and information elements in
   two segments: 1) the Wi-Fi segment and 2) the PMIPv6 segment.  (See
   Figure 1.)  The recommendations here allow for dynamic QoS policy
   information per Mobile Node (MN) and session to be configured by the
   IEEE 802.11 access network.  PMIPv6 QoS signaling between the Mobile
   Access Gateway (MAG) and Local Mobility Anchor (LMA) provisions the
   per-MN QoS policies in the MAG.  Further details on policy
   configuration and the Policy Control Function (PCF) can be found in
   [1], Section 6.1.  In the IEEE 802.11 access network modeled here,
   the MAG is located at the AP / Wireless LAN Controller (WLC).
   Figure 1 below provides an overview of the entities and protocols.

                                   +-----+                +-------+
                                   | AAA |                |  PCF  |
                                   +--+--+                +---+---+
                                      |                       |
                                      |                       |
       +----+                      +--+--------+          +---+---+
       |    | IEEE 802.11, WMM-AC  |+-++  +---+|  PMIPv6  |       |
       | MN <---------------------->|AP+--+MAG|<==========>  LMA  |
       |    |   (ADDTS, DELTS)     |+--+  +---+|   QoS    |       |
       +----+                      +-----------+          +-------+

       Figure 1: End-to-End QoS in Networks with IEEE 802.11 Access

   The MN and Access Point (AP) use IEEE 802.11 QoS mechanisms to set up
   QoS flows in the Wi-Fi segment.  The MAG and LMA set up QoS flows
   using PMIPv6 QoS procedures.  The protocols and mechanisms between
   the AP and MAG are outside the scope of this document.  Some
   implementations may have the AP and MAG in the same network node.
   However, this document does not exclude various deployments including
   those in which the AP and WLC are separate nodes or in which the MAG
   control and data planes are separate.

   The recommendations in this document use IEEE 802.11 QoS and PMIPv6
   QoS mechanisms [1].  State machines for QoS policy setup in IEEE
   802.11 and PMIPv6 operate differently.  Guidelines for installing QoS
   in the MN using IEEE 802.11 and PMIPv6 segments and for mapping
   parameters between them are outlined below.

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   - Procedure Mapping:

       PMIPv6-defined procedures for QoS setup, as specified in [1], may
       be triggered by the LMA or MAG.  IEEE 802.11 QoS setup, on the
       other hand, is always triggered by the MN (IEEE 802.11 QoS
       Station (QSTA)).  The end-to-end QoS setup across these network
       segments should accommodate QoS that is triggered by the network
       or by the end user.

   - Parameter Mapping:

       There is no systematic method of mapping of specific parameters
       between PMIPv6 QoS parameters and IEEE 802.11 QoS.  For example,
       parameters like Allocation and Retention Priority (AARP) in
       PMIPv6 QoS have no equivalent in IEEE 802.11.

   The primary emphasis of this specification is to handle the
   interworking between WMM-AC signaling/procedures and PMIPv6 QoS
   signaling/procedures.  When the client does not support WMM-AC, then
   the AP/MAG uses the connection mapping in Table 2 and DSCP-to-AC
   mapping as shown in Table 3.

   The rest of the document is organized as follows.  Section 2 provides
   an overview of IEEE 802.11 QoS.  Section 3 describes a mapping of QoS
   signaling procedures between IEEE 802.11 and PMIPv6.  The mapping of
   parameters between IEEE 802.11 and PMIPv6 QoS is described in
   Section 4.

1.1.  Abbreviations

   AAA     Authentication, Authorization, and Accounting
   AARP    Allocation and Retention Priority
   AC      Access Category
   ADDTS   ADD Traffic Stream
   AIFS    Arbitration Inter-Frame Space
   ALG     Application Layer Gateway
   AMBR    Aggregate Maximum Bit Rate
   AP      Access Point
   CW      Contention Window
   DELTS   DELete Traffic Stream
   DL      DownLink
   DSCP    Differentiated Services Code Point
   DPI     Deep Packet Inspection
   EDCA    Enhanced Distributed Channel Access
   EPC     Evolved Packet Core
   GBR     Guaranteed Bit Rate
   MAC     Media Access Control
   MAG     Mobile Access Gateway

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   MBR     Maximum Bit Rate
   MN      Mobile Node
   MSDU    Media Access Control Service Data Unit
   PBA     Proxy Binding Acknowledgement
   PBU     Proxy Binding Update
   PCF     Policy Control Function
   PHY     Physical Layer
   QCI     QoS Class Identifier
   QoS     Quality of Service
   QSTA    QoS Station
   SIP     Session Initiation Protocol
   STA     Station
   TC      Traffic Class
   TCLAS   Type Classification
   TCP     Transmission Control Protocol
   TS      Traffic Stream
   TSPEC   Traffic Conditioning Specification
   UDP     User Datagram Protocol
   UL      UpLink
   UP      User Priority
   WLAN    Wireless Local Area Network
   WLC     Wireless Controller
   WMM     Wi-Fi MultiMedia
   WMM-AC  Wi-Fi MultiMedia Admission Control

1.2.  Definitions

   Peak Data Rate

      In WMM-AC, Peak Data Rate specifies the maximum data rate in bits
      per second.  The Maximum Data Rate does not include the MAC and
      PHY overheads [4].  Data rate includes the transport of the IP
      packet and header.

      TSPECs for both uplink and downlink may contain Peak Data Rate.

   Mean Data Rate

      This is the average data rate in bits per second.  The Mean Data
      Rate does not include the MAC and PHY overheads [4].  Data rate
      includes the transport of the IP packet and header.

      TSPECs for both uplink and downlink must contain the Mean Data
      Rate.

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   Minimum Data Rate

      In WMM-AC, Minimum Data Rate specifies the minimum data rate in
      bits per second.  The Minimum Data Rate does not include the MAC
      and PHY overheads [4].  Data rate includes the transport of the IP
      packet and header.

      Minimum Data Rate is not used in QoS provisioning as it is
      described here.

   QCI

      The QoS Class Identifier (QCI) is a scalar parameter that points
      to standardized characteristics of QoS as opposed to signaling
      separate parameters for resource type, priority, delay, and loss
      [8].

   STA

      A station (STA) is a device that has the capability to use the
      IEEE 802.11 protocol.  For example, a station maybe a laptop, a
      desktop PC, an access point, or a Wi-Fi phone [3].

      An STA that implements the QoS facility is a QoS Station (QSTA)
      [3].

   TSPEC

      The TSPEC element in IEEE 802.11 contains the set of parameters
      that define the characteristics and QoS expectations of a traffic
      flow [3].

   TCLAS

      The TCLAS element specifies an element that contains a set of
      parameters necessary to identify incoming MSDUs (MAC Service Data
      Units) that belong to a particular TS (Traffic Stream) [3].

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2.  Overview of IEEE 802.11 QoS

   IEEE 802.11 defines a way of providing prioritized access for
   different traffic classes (video, voice, etc.) by a mechanism called
   EDCA (Enhanced Distributed Channel Access).  The levels of priority
   in EDCA are called access categories (ACs) and there are four levels
   (in decreasing order of priority): Voice, Video, Best-Effort, and
   Background.  Prioritized access is achieved by using AC-specific
   values for Contention Window (CW) and Arbitration Inter-Frame Space
   (AIFS).  (Higher-priority categories have smaller values for minimum
   and maximum CW and AIFS.)

   A subset of the QoS mechanisms is defined in WMM -- a Wi-Fi Alliance
   certification of support for a set of features from an IEEE 802.11e
   draft (now part of IEEE 802.11).  This certification is for both
   clients and APs and certifies the operation of WMM.  WMM is primarily
   the implementation of the EDCA component of IEEE 802.11e.  WMM uses
   the IEEE 802.1P classification scheme developed by the IEEE (which is
   now a part of the 802.1D specification).  The IEEE 802.1P
   classification scheme has eight priorities, which WMM maps to four
   access categories: AC_BK, AC_BE, AC_VI, and AC_VO.  The lack of
   support in WMM for the TCLAS (used in identifying an IP flow) has an
   impact on the QoS provisioning.  The impact on WMM-based QoS
   provisioning is described in Sections 3 and 4.

   IEEE 802.11 defines the way a (non-AP) STA can request QoS to be
   reserved for an access category.  Correspondingly, the AP can
   determine whether to admit or deny the request depending on the
   available resources.  Further, the AP may require that Admission
   Control is mandatory for an access category.  In such a case, the STA
   is expected to use the access category only after being successfully
   admitted.  WMM-AC is a Wi-Fi Alliance certification of support for
   Admission Control based on a set of features in IEEE 802.11.

   The QoS signaling in IEEE 802.11 is initiated by the (non-AP) STA (by
   sending an ADDTS request).  This specification references procedures
   in IEEE 802.11, WMM, and WMM-AC.

3.  Mapping QoS Procedures between IEEE 802.11 and PMIPv6

   There are two main types of interaction possible to provision QoS for
   flows that require Admission Control -- one where the MN initiates
   the QoS request and the network provisions the resources.  The second
   is where the network provisions resources as a result of a PMIPv6 QoS
   request.  In the second scenario, the LMA can push the QoS
   configuration to the MAG.  However, there is no standard way for the
   AP to initiate a QoS service request to the MN.  Recommendations to
   set up QoS in both these cases are described in this section.

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3.1.  MN-Initiated QoS Service Request

3.1.1.  MN-Initiated QoS Reservation Request

   This procedure outlines the case where the MN is configured to start
   the QoS signaling.  In this case, the MN sends an ADDTS request
   indicating the QoS required for the flow.  The AP/MAG obtains the
   corresponding level of QoS to be granted to the flow by using the
   PMIPv6 PBU/PBA sequence that contains the QoS options exchanged with
   the LMA.  Details of the QoS provisioning for the flow are provided
   below.

                                 +-----------+
    +----+                       |+--+  +---+|            +-------+
    | MN |                       ||AP|  |MAG||            |  LMA  |
    +-+--+                       ++-++--+-+-++            +---+---+
      |                             |     |                   |
    +-------------------------------------------------------------+
    |          (0) establish session with mobile network          |
    +-------------------------------------------------------------+
      |                             |     |                   |
    +-------------+                 |     |                   |
    |upper-layer  |                 |     |                   |
    |notification |                 |     |                   |
    +-+-+-+-+-+-+-+                 |     |                   |
      |                             |     |                   |
      | ADDTS Request(TCLAS(opt),TSPEC),AC|                   |
      |---------------------------->|     |                   |
      |             (1)             |---->|PBU(QoS options)(2)|
      |                             |     |------------------>|
      |                             |     |                   | Policy
      |                             |     |PBA(QoS option)(3) |<----->
      |                             |     |<------------------|
      |                             |<----|                   |
      |ADDTS Response(TCLAS(opt),TSPEC),AC|                   |
      |<----------------------------|     |                   |
      |             (4)             |     |

                Figure 2: MS-Initiated QoS Service Request

   In the use case shown in Figure 2, the MN initiates the QoS service
   request.

   (0) The MN establishes a session as described in steps 1-4 of Use
       Case 2 (MAG-Initiated QoS Service Request) in Section 3.1 of [1].
       At this point, a connection with a PMIPv6 tunnel is established
       to the LMA.  This allows the MN to start application-level
       signaling.

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   (1) The trigger for the MN to request QoS is an upper-layer
       notification.  This may be the result of end-to-end application
       signaling and setup procedures (e.g., SIP [10]).

       Since the MN is configured to start QoS signaling, it sends an
       ADDTS request with TSPEC and TCLAS identifying the flow for which
       QoS is requested.

       It should be noted that WMM-AC specifications do not contain
       TCLAS.  When TCLAS is not present, there is no direct way to
       derive flow-specific attributes like Traffic Selector in PMIPv6.
       In this case, functionality to derive IP flow details from
       information in upper-layer protocols (e.g., SIP [10]) and
       associate them with a subsequent QoS request may be used.  This
       is not described further here, but it may be functionality in an
       Application Layer Gateway (ALG) or Deep Packet Inspection (DPI).
       It should be noted that an ALG or DPI can increase the complexity
       of the AP/MAG implementation and affect its scalability.  If no
       TCLAS is derived, the reservation applies to all flows of the MN.
       Parameter mapping in this case is shown in Table 2.

   (2) If there are sufficient resources at the AP/WLC to satisfy the
       request, the MAG sends a PBU with QoS options, Operational Code
       ALLOCATE, and the Traffic Selector identifying the flow.  The
       Traffic Selector is derived from the TCLAS to identify the flow
       requesting QoS.  IEEE 802.11 QoS parameters in TSPEC are mapped
       to PMIPv6 parameters.  The mapping of TCLAS to PMIPv6 is shown in
       Table 1.  TSPEC parameter mapping is shown in Table 4.

       If TCLAS is not present (when WMM-AC is used), TCLAS may be
       derived from information in upper-layer protocols (as described
       in step 1) and populated in the Traffic Selector.  If TCLAS
       cannot be derived, the Traffic Selector field is not included in
       the QoS options.

   (3) The LMA obtains the authorized QoS for the flow and responds to
       the MAG with Operational Code set to RESPONSE.  Mapping of PMIPv6
       to IEEE 802.11 TCLAS is shown in Table 1, and mapping of TSPEC
       parameters is shown in Table 4.

       Reserved bandwidth for flows is calculated separately from the
       non-reserved session bandwidth.  The Traffic Selector identifies
       the flow for which the QoS reservations are made.

       If the LMA offers downgraded QoS values to the MAG, it should
       send a PBU to the LMA with Operational Code set to DE-ALLOCATE.
       (The LMA would respond with PBA to confirm completion of the
       request.)

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   (4) The AP/MAG provisions the corresponding QoS and replies with
       ADDTS Response containing authorized QoS in TSPEC, the flow
       identification in TSPEC, and ResultCode set to SUCCESS.

       The AP polices these flows according to the QoS provisioning.

       In step 3, if the LMA sends a downgraded QoS or a PBA message
       with status code CANNOT_MEET_QOS_SERVICE_REQUEST (179), then the
       AP should respond to the MN with ADDTS Response and ResultCode
       set as follows:

       -  for downgraded QoS from LMA, ResultCode is set to
          REJECTED_WITH_SUGGESTED_CHANGES.  Downgraded QoS values from
          LMA are mapped to TSPEC as per Table 4.  This is still a
          rejection, but the MN may revise the QoS to a lower level and
          repeat this sequence if the application can adapt.

       -  if LMA cannot meet the QoS service request, ResultCode is set
          to TCLAS_RESOURCES_EXHAUSTED.

       Either REJECTED_WITH_SUGGESTED_CHANGES or
       TCLAS_RESOURCES_EXHAUSTED results in the rejection of the QoS
       reservation, but it does not cause the removal of the session
       itself.

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3.1.2.  MN-Initiated QoS De-allocation Request

   QoS resources reserved for a session are released on completion of
   the session.  When the application session completes, the LMA or the
   MN may signal for the release of resources.  In the use case shown in
   Figure 3, the MN initiates the release of QoS resources.

                                 +-----------+
    +----+                       |+--+  +---+|             +-------+
    | MN |                       ||AP|  |MAG||             |  LMA  |
    +-+--+                       ++-++--+-+-++             +---+---+
      |                             |     |                    |
    +-------------------------------------------------------------+
    |         (0) Establishment of application session            |
    |              and reservation of QoS resources               |
    |                                                             |
    |                   (Session in progress)                     |
    |                                                             |
    |               Release of application session                |
    +-------------------------------------------------------------+
      |                             |     |                    |
      | DELTS Request (TS INFO)(1)  |     |                    |
      |---------------------------->|     |                    |
      |                             |---->|                    |
      |                             |<----|                    |
      | DELTS Response (TS INFO)(2) |     |                    |
      |<----------------------------|     |                    |
      |                             |     |PBU(QoS,DE-ALLOC)(3)|
      |                             |     |------------------->|Policy
      |                             |     |                    |<---->
      |                             |     |                    |Update
      |                             |     |PBA(QoS,RESPONSE)(4)|
      |                             |     |<-------------------|
      |                             |     |                    |

                Figure 3: MN-Initiated QoS Resource Release

   (0) The MN establishes and reserves QoS resources.  When the
       application session terminates, the MN prepares to release QoS
       resources.

   (1) The MN releases its own internal resources and sends a DELTS
       Request to the AP with TS (Traffic Stream) INFO.

   (2) The AP receives the DELTS request, releases local resources, and
       responds to the MN with a DELTS response.

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   (3) The MAG initiates a PBU, with the Operational Code set to
       DE-ALLOCATE, and with the Traffic Selector constructed from TCLAS
       and PMIPv6 QoS parameters from TSPEC.

       When TCLAS is not present, the MAG should de-allocate all flows
       with the same access category as indicated in the DELTS Request.
       In the typical case, if the client does not support TCLAS and
       only MN-initiated QoS Service requests are supported, then the
       MAG will have at most one QoS Service request per access
       category.

   (4) LMA receives the PBU and releases local resources.  The LMA then
       responds with a PBA.

   It should be noted that steps 3 and 4 can proceed independently of
   the DELTS Response (step 2).

3.2.  LMA-Initiated QoS Service Request

3.2.1.  LMA-Initiated QoS Reservation Request

   This section describes the case when the QoS service request is
   initiated by the LMA.  For example, an application such as voice may
   request the network to initiate configuration of additional QoS
   policy as in [8], Section 7.4.2.  In the current WLAN specifications,
   there is no standard-defined way for the AP to initiate a QoS service
   request to the MN.  As a result, when the MAG receives a QoS request
   from the LMA, it does not have any standard mechanisms to initiate
   any QoS requests to the MN over the access network.  Given this, the
   PMIPv6 QoS service requests and any potential WLAN service requests
   (such as described in Section 3.1) are handled asynchronously.

   The PMIPv6 QoS service requests and WLAN QoS service request could
   still be coordinated to provide an end-to-end QoS.  If the MAG
   receives an Update Notification (UPN) request from the LMA to reserve
   QoS resources for which it has no corresponding QoS request from the
   MN, the MAG may, in consultation with the AP, provision a policy that
   can grant a subsequent QoS request from the MN.  If the MN initiates
   QoS procedures after the completion of PMIPv6 QoS procedures, the AP/
   MAG can ensure consistency between the QoS resources in the access
   network and QoS resources between the MAG and LMA.

   For example, if the MN is requesting a mean data rate of x Mbps, the
   AP and MAG can ensure that the rate can be supported on the network
   between MAG and LMA based on previous PMIPv6 QoS procedures.  If the
   MN subsequently requests data rates of x Mbps or less, the AP can
   accept a request based on the earlier PMIPv6 QoS provisioning.  For
   the case where there is a mismatch, i.e., the network does not

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   support the x Mbps, then either the MAG should renegotiate the QoS
   resource and ask for increased QoS resources or the AP should reject
   the QoS request.

3.2.2.  Discussion on QoS Request Handling with IEEE 802.11aa

   The network-initiated QoS service request scenario poses some
   challenges outlined here.  IEEE 802.11 does not provide any
   mechanisms for the AP to initiate a QoS request.  As a result, the
   AP/MAG cannot explicitly make any reservations in response to a QoS
   reservation request made using UPN.  IEEE 802.11aa [5] (which is an
   amendment to IEEE 802.11) has a mechanism that enables the AP to ask
   the client to reserve QoS for a traffic stream.  It does this via the
   ADDTS Reserve Request.  The ADDTS Reserve Request contains a TSPEC,
   an optional TCLAS, and a mandatory stream identifier.  The
   specification does not describe how the AP would obtain such a stream
   identifier.  As a result, there needs to be a new higher-layer
   protocol defined that is understood by the MN and AP and that
   provides a common stream identifier to both ends.  Alternately, the
   IEEE 802.11aa specification could be modified to make the usage
   optional.  When (or if) the stream identifier is made optional, the
   TCLAS can provide information about the traffic stream.

   Appendix A outlines a protocol sequence with PMIPv6 UPN / Update
   Notification Acknowledgement (UPA) if the above IEEE 802.11aa issues
   can be resolved.

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3.2.3.  LMA-Initiated QoS De-allocation Request

   QoS resources reserved for a session are released on completion of
   the session.  When the application session completes, the LMA or the
   MN may signal for the release of resources.  In this use case, the
   network initiates the release of QoS resources.

                                  +-----------+
    +----+                       |+--+  +---+|            +-------+
    | MN |                       ||AP|  |MAG||            |  LMA  |
    +-+--+                       ++-++--+-+-++            +---+---+
      |                             |     |                   |
    +-------------------------------------------------------------+
    |             Establishment of application session            |
    |              and reservation of QoS resources               |
    |                                                             |
    |                   (Session in progress)                     |
    |                                                             |
    |               Release of application session                |
    +-------------------------------------------------------------+
      |                             |     |                   | Policy
      |                             |     |                   |<------
      |                             |     |UPN(QoS,DE-ALLOC)  |
      |                             |     |<------------------|
      |                             |<----|        (1)        |
      |                             |---->|UPA(QoS,RESPONSE)  |
      |                             |     |------------------>|
      |                             |     |        (2)        |
      |                             |     |                   |
      | DELTS Request (TS INFO)(3)  |     |                   |
      |<----------------------------|     |                   |
      | DELTS Response (TS INFO)(4) |     |                   |
      |---------------------------->|     |                   |
      |                             |     |                   |

               Figure 4: LMA-Initiated QoS Resource Release

   In the use case shown in Figure 4, the network initiates the release
   of QoS resources.  When the application session terminates, the LMA
   receives notification of that event.  The LMA releases local QoS
   resources associated with the flow and initiates signaling to release
   QoS resources in the network.

   (1) The LMA sends a UPN with QoS options identifying the flow for
       which QoS resources are to be released and Operational Code set
       to DE-ALLOCATE.  No additional LMA QoS parameters are sent.

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   (2) The MAG replies with a UPA confirming the acceptance and
       Operational Code set to RESPONSE.

   (3) The AP/WLC (MAG) releases local QoS resources associated with the
       flow.  The AP derives the corresponding access category from the
       Traffic Class (TC) field provided in the QoS option.  In
       addition, if the AP supports TCLAS and the QoS option contains a
       Traffic Selector field, then the AP shall map the Traffic
       Selector into a TCLAS element.  In the case where the AP does not
       support TCLAS (for example, an AP compliant with WMM-AC), then
       the AP shall only use the access category.  The AP sends a DELTS
       Request with TS INFO identifying the reservation.

   (4) The MN sends DELTS Response confirming release.

   It should be noted that steps 3 and 4 can proceed independently of
   the UPA (step 2).

4.  Mapping between IEEE 802.11 QoS and PMIPv6 QoS Parameters

4.1.  Connection Parameters

   TSPEC in IEEE 802.11 is used to reserve QoS for a traffic stream (MN
   MAC, TS ID).  The IEEE 802.11 QoS reservation is for IEEE 802.11
   frames associated with an MN's MAC address.

   The TCLAS element with Classifier 1 (TCP/UDP Parameters) is used to
   identify a PMIPv6 QoS flow.  We should note that WMM-AC procedures do
   not support TCLAS.  When TCLAS is present, a one-to-one mapping
   between the TCLAS-defined flow and the Traffic Selector is given
   below.

   QoS reservations in IEEE 802.11 are made for a traffic stream
   (identified in TCLAS) and correspond to PMIPv6 QoS session parameters
   (identified by the Traffic Selector).  PMIPv6 QoS [1] specifies that
   when QoS-Traffic-Selector is included along with the per-session
   bandwidth attributes described in Section 4.3 below, the attributes
   apply at a per-session level.

      +--------------------------------+----------------------------+
      |    MN <--> AP (IEEE 802.11)    |   MAG <--> LMA (PMIPv6)    |
      +--------------------------------+----------------------------+
      | (TCLAS Classifier 1)TCP/UDP IP | Traffic Selector (IP flow) |
      |   (TCLAS Classifier 1) DSCP    |     Traffic Class (TC)     |
      +--------------------------------+----------------------------+

           Table 1: IEEE 802.11 - PMIPv6 QoS Connection Mapping

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   If the MN or AP is not able to convey flow parameters in TCLAS, the
   QoS reservation request in IEEE 802.11 is derived as shown in
   Table 2.

        +------------------------------+--------------------------+
        |       MN <--> AP (WMM)       | MAG <--> LMA (PMIPv6)    |
        +------------------------------+--------------------------+
        | (no IP flow parameter/TCLAS) | (a) applies to all flows |
        |                              | (b) derived out-of-band  |
        |                              |                          |
        |    User Priority (802.1D)    | Traffic Class (TC)       |
        |                              | (derived using Table 3)  |
        +------------------------------+--------------------------+

               Table 2: WMM - PMIPv6 QoS Connection Mapping

   When WMM [4] is used, and TCLAS is not present to specify IP flow,
   one of two options apply for the MAG - LMA (PMIPv6) segment:

   (a) Bandwidth parameters described in Section 4.3 apply to all flows
       of the MN.  This is not a preferred mode of operation if the LMA
       performs reservation for a single flow, e.g., a voice flow
       identified by an IP 5-tuple.

   (b) The IP flow for which the MN requests reservation is derived out-
       of-band.  For example, the AP/MAG observes application-level
       signaling (e.g., SIP [10]) or session-level signaling (e.g., 3GPP
       WLCP (WLAN Control Protocol) [7]), associates subsequent ADDTS
       requests using heuristics, and then derives the IP flow / Traffic
       Selector field.

4.2.  QoS Class

   Table 3 contains a mapping between access category (AC) and IEEE
   802.1D User Priority (UP) tag in IEEE 802.11 frames, and DSCP in IP
   data packets.  The table also provides the mapping between AC and
   DSCP for use in IEEE 802.11 TSPEC and PMIPv6 QoS (Traffic Class).
   Mapping of QCI to DSCP uses the tables in [6].

Top      ToC       Page 17 
        +-----+------+-----------+---------+----------------------+
        | QCI | DSCP | 802.1D UP |    AC   | Example Services     |
        +-----+------+-----------+---------+----------------------+
        |  1  |  EF  |   6(VO)   | 3 AC_VO | conversational voice |
        |  2  |  EF  |   6(VO)   | 3 AC_VO | conversational video |
        |  3  |  EF  |   6(VO)   | 3 AC_VO | real-time gaming     |
        |  4  | AF41 |   5(VI)   | 2 AC_VI | buffered streaming   |
        |  5  | AF31 |   4(CL)   | 2 AC_VI | signaling            |
        |  6  | AF32 |   4(CL)   | 2 AC_VI | buffered streaming   |
        |  7  | AF21 |   3(EE)   | 0 AC_BE | interactive gaming   |
        |  8  | AF11 |   1(BE)   | 0 AC_BE | web access           |
        |  9  |  BE  |   0(BK)   | 1 AC_BK | email                |
        +-----+------+-----------+---------+----------------------+

           Table 3: QoS Mapping between QCI/DSCP, 802.1D UP, AC

   The MN tags all data packets with DSCP and IEEE 802.1D UP
   corresponding to the application and the subscribed policy or
   authorization.  The AP polices sessions and flows based on the
   configured QoS policy values for the MN.

   For QoS reservations, TSPEC uses WMM-AC values and PMIPv6 QoS uses
   corresponding DSCP values in Traffic Class (TC).  IEEE 802.11 QoS
   Access Category AC_VO and AC_VI are used for QoS reservations.  AC_BE
   and AC_BK should not be used in reservations.

   When WMM-AC specifications that do not contain TCLAS are used, it is
   only possible to have one reservation per Traffic Class / access
   category.  PMIPv6 QoS will not contain any flow-specific attributes
   like Traffic Selector.

4.3.  Bandwidth

   Bandwidth parameters that need to be mapped between IEEE 802.11 and
   PMIPv6 QoS are shown in Table 4.

          +-------------------------+---------------------------+
          | MN <--> AP(IEEE 802.11) | MAG <--> LMA (PMIPv6)     |
          +-------------------------+---------------------------+
          |    Mean Data Rate, DL   | Guaranteed-DL-Bit-Rate    |
          |    Mean Data Rate, UL   | Guaranteed-UL-Bit-Rate    |
          |    Peak Data Rate, DL   | Aggregate-Max-DL-Bit-Rate |
          |    Peak Data Rate, UL   | Aggregate-Max-UL-Bit-Rate |
          +-------------------------+---------------------------+

       Table 4: Bandwidth Parameters for Admission-Controlled Flows

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   In PMIPv6 QoS [1], services using a sending rate smaller than or
   equal to the Guaranteed Bit Rate (GBR) can assume, in general, that
   congestion-related packet drops will not occur [8].  If the rate
   offered by the service exceeds this threshold, there are no
   guarantees provided.  IEEE 802.11 radio networks do not offer such a
   guarantee, but [4] notes that the application (service) requirements
   are captured in TSPEC by the MSDU (MAC Service Data Unit) and Mean
   Data Rate.  The TSPEC should contain Mean Data Rate, and it is
   recommended that it be mapped to the GBR parameters, Guaranteed-DL-
   Bit-Rate and Guaranteed-UL-Bit-Rate in PMIPv6 QoS [1].

   IEEE 802.11 TSPEC requests do not require all fields to be completed.
   [4] specifies a list of TSPEC parameters that are required in the
   specification.  Peak Data Rate is not required in WMM; however, for
   MNs and APs that are capable of specifying the Peak Data Rate, it
   should be mapped to MBR (Maximum Bit Rate) in PMIPv6 QoS.  The AP
   should use the MBR parameters Aggregate-Max-DL-Bit-Rate and
   Aggregate-Max-UL-Bit-Rate to police these flows on the backhaul
   segment between MAG and LMA.

   During the QoS reservation procedure, if the MN requests Mean Data
   Rate, or Peak Data Rate in excess of values authorized in PMIPv6 QoS,
   the AP should deny the request in an ADDTS response.  The AP may set
   the reject cause code to REJECTED_WITH_SUGGESTED_CHANGES and send a
   revised TSPEC with Mean Data Rate and Peak Data Rate set to
   acceptable GBR and MBR, respectively, in PMIPv6 QoS.

5.  Security Considerations

   This document describes mapping of PMIPv6 QoS parameters to IEEE
   802.11 QoS parameters.  Thus, the security in the WLAN and PMIPv6
   signaling segments and the functional entities that map the two
   protocols need to be considered.  IEEE 802.11 [3] provides the means
   to secure management frames that are used for ADDTS and DELTS.  The
   PMIPv6 specification [9] recommends using IPsec and IKEv2 to secure
   protocol messages.  The security of the node(s) that implement the
   QoS mapping functionality should be considered in actual deployments.

   The QoS mappings themselves do not introduce additional security
   concerns.

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6.  References

6.1.  Normative References

   [1]  Liebsch, M., Seite, P., Yokota, H., Korhonen, J., and S.
        Gundavelli, "Quality-of-Service Option for Proxy Mobile IPv6",
        RFC 7222, DOI 10.17487/RFC7222, May 2014,
        <http://www.rfc-editor.org/info/rfc7222>.

   [2]  Krishnan, S., Gundavelli, S., Liebsch, M., Yokota, H., and J.
        Korhonen, "Update Notifications for Proxy Mobile IPv6",
        RFC 7077, DOI 10.17487/RFC7077, November 2013,
        <http://www.rfc-editor.org/info/rfc7077>.

6.2.  Informative References

   [3]  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 Standard 802.11.

   [4]  Wi-Fi Alliance, "Wi-Fi Multimedia Technical Specification (with
        WMM-Power Save and WMM-Admission Control)", Version 1.2.0, May
        2012.

   [5]  IEEE, "Wireless LAN Medium Access Control (MAC) and Physical
        Layer (PHY) Specification, Amendment 2: MAC Enhancements for
        Robust Audio Video Streaming", IEEE 802.11aa.

   [6]  3GPP, "Guidelines for IPX Provider networks (Previously
        Inter-Service Provider IP Backbone Guidelines)", GSMA Official
        Document IR.34 v11.0, November 2014,
        <http://www.gsma.com/newsroom/wp-content/uploads/
        IR.34-v11.0.pdf>.

   [7]  3GPP, "Technical Specification Group Core Network and Services;
        Wireless LAN control plane protocols for trusted WLAN access to
        EPC; Stage 3 (Release 12)", 3GPP TS 23.244 12.1.0, December
        2014, <http://www.3gpp.org/ftp/specs/archive/24_series/24.244/>.

   [8]  3GPP, "Technical Specification Group Services and System
        Aspects; Policy and Charging Control Architecture (Release 13)",
        3GPP TS 23.203 13.2.0, December 2014,
        <http://www.3gpp.org/ftp/specs/archive/23_series/23.203/>.

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   [9]  Gundavelli, S., Ed., Leung, K., Devarapalli, V., Chowdhury, K.,
        and B. Patil, "Proxy Mobile IPv6", RFC 5213,
        DOI 10.17487/RFC5213, August 2008,
        <http://www.rfc-editor.org/info/rfc5213>.

   [10] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
        Peterson, J., Sparks, R., Handley, M., and E.  Schooler, "SIP:
        Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261,
        June 2002, <http://www.rfc-editor.org/info/rfc3261>.

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Appendix A.  LMA-Initiated QoS Service Flow with IEEE 802.11aa

                              +-----------+
    +----+                    |+--+  +---+|           +-------+
    | MN |                    ||AP|  |MAG||           |  LMA  |
    +-+--+                    ++-++--+-+-++           +---+---+
      |                          |     |                  |
    +----------------------------------------------------------------+
    |         (0) establish session with mobile network              |
    +----------------------------------------------------------------+
      |                          |     |                  |
      |                          |     |                  | Policy
      |                          |     |                  |<----------
      |                          |     |UPN(QoS opt(2)    | Update(1)
      | ADDTS Reserve Request    |     |<-----------------|
      |      (TCLAS, TSPEC)(3)   |<----|                  |
      |<-------------------------|     |                  |
      | ADDTS Reserve Response   |     |                  |
      |      (TCLAS, TSPEC)(4)   |     |                  |
      |------------------------->|     |                  |
      |                          |---->|UPA(QoS opt)(5)   |
      |                          |     |----------------->|
      |                          |     |                  |

         Figure 5: LMA-Initiated QoS Service Request with 802.11aa

   In the use case shown in Figure 5, the LMA initiates the QoS service
   request and IEEE 802.11aa is used to set up the QoS reservation in
   the Wi-Fi segment.

   (0) The MN sets up a best-effort session.  This allows the MN to
       perform application-level signaling and setup.

   (1) The policy server sends a QoS reservation request to the LMA.
       This is usually sent in response to an application that requests
       the policy server for higher QoS for some of its flows.

       The LMA reserves resources for the flow requested.

   (2) The LMA sends a PMIPv6 UPN (Update Notification) [2], as outlined
       in Section 3.2.1, to the MAG with Notification Reason set to
       QOS_SERVICE_REQUEST and Acknowledgement Requested flag set to 1.
       The Operational Code in the QoS option is set to ALLOCATE, and
       the Traffic Selector identifies the flow for QoS.

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       The LMA QoS parameters include Guaranteed-DL-Bit-Rate/Guaranteed-
       UL-Bit-Rate and Aggregate-Max-DL-Bit-Rate/Aggregate-Max-UL-Bit-
       Rate for the flow.  The reserved bandwidth for flows is
       calculated separately from the non-reserved session bandwidth.

   (3) If there are sufficient resources to satisfy the request, the AP/
       MAG sends an ADDTS Reserve Request (IEEE 802.11aa) specifying the
       QoS reserved for the traffic stream, including the TSPEC and
       TCLAS elements mapped from the PMIPv6 QoS Traffic Selector to
       identify the flow.

       PMIPv6 parameters are mapped to TCLAS (Table 1) and TSPEC
       (Table 4).  If there are insufficient resources at the AP/WLC,
       the MAG will not send an ADDTS message and will continue the
       processing of step 5.

       The higher-level stream identifier in IEEE 802.11aa should be
       encoded as discussed in Section 3.2.2.

   (4) MN accepts the QoS reserved in the network and replies with ADDTS
       Reserve Response.

   (5) The MAG (AP/WLC) replies with a UPA confirming the acceptance of
       QoS options and Operational Code set to RESPONSE.  The AP/WLC
       polices flows based on the new QoS.

       If there are insufficient resources at the AP in step 3, the MAG
       sends a response with UPA status code set to
       CANNOT_MEET_QOS_SERVICE_REQUEST (130).

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Acknowledgements

   The authors thank the NETEXT Working Group for the valuable feedback
   to different versions of this specification.  In particular, the
   authors wish to thank Sri Gundavelli, Georgios Karagianis, Rajeev
   Koodli, Kent Leung, Marco Liebsch, Basavaraj Patil, Pierrick Seite,
   and Hidetoshi Yokota for their suggestions and valuable input.  The
   authors also thank George Calcev, Mirko Schramm, Mazin Shalash, and
   Marco Spini for detailed input on parameters and scheduling in IEEE
   802.11 and 3GPP radio networks.

Authors' Addresses

   John Kaippallimalil
   Huawei
   5340 Legacy Dr., Suite 175
   Plano, TX  75024
   United States

   EMail: john.kaippallimalil@huawei.com


   Rajesh Pazhyannur
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   United States

   EMail: rpazhyan@cisco.com


   Parviz Yegani
   Juniper
   1194 North Mathilda Ave.
   Sunnyvale, CA  94089-1206
   United States

   EMail: pyegani@juniper.net