INTERNET-DRAFT John Kaippallimalil
Intended Status: Informational Huawei
Expires: April 17, 2014 Rajesh S. Pazhyannur
Cisco
Parviz Yegani
Juniper
October 14, 2013
Mapping Wi-Fi QoS in a PMIPv6 Mobility Domain
draft-kaippallimalil-netext-pmip-qos-wifi-03
Abstract
This document provides a specification to enable end to end QoS in
networks containing a Wi-Fi network coupled with a PMIPv6 mobility
domain consisting of a local mobility anchor and mobility access
gateway. This enables QoS policing and labeling of packets in a
consistent manner on the 802.11 link between the MN and the AP as
well as the link between the MAG and the LMA. To enable this, the
document specifies mapping between QoS parameters on the 802.11 link
and the QoS Mobility options in the PMIPv6 domain.
Status of this Memo
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Copyright and License Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . 4
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. QoS in 3GPP based Networks . . . . . . . . . . . . . . . . 4
2.2. QoS in PMIPv6 Mobility domain . . . . . . . . . . . . . . . 5
2.3. QoS in IEEE 802.11 based Networks . . . . . . . . . . . . . 5
3. End-to-End QoS with Admission Control . . . . . . . . . . . . . 6
3.1. Case A: MN Initiated QoS Signaling . . . . . . . . . . . . 6
3.2. Case B: Network Initiated QoS Signaling (802.11aa based) . 7
3.3. Case C: Hybrid (Network Initiated for PMIPv6 and MN
initiated for Wi-Fi) . . . . . . . . . . . . . . . . . . . 9
3.4. Mapping of Connection Parameters . . . . . . . . . . . . . 10
3.5. Service Guarantees in 802.11 . . . . . . . . . . . . . . . 11
4. End-to-End QoS without Admission Control . . . . . . . . . . . 11
4.1. Default Values and Recommendations . . . . . . . . . . . . 13
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 13
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References . . . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
Appendix A: QoS Policy Architecture . . . . . . . . . . . . . . . 16
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1. Introduction
The deployment network considered here is where there is a Wi-Fi
access link coupled with a PMIPv6 mobility domain. A MAG is co-
located with the Access Point (AP) and in cases where the Wi-Fi
network consists of Access Point and a Wireless LAN Controller (WLC),
we assume that the MAG is located either at the AP or the WLC.
Additionally, the Wi-Fi access network may be part of a 3GPP network.
In such a case, the per user QoS Policy may be provided from the 3GPP
network. Specifically, the 3GPP network may provision QoS during
authorization of the user, and may also dynamically provision QoS for
individual flows. [TS23.402] [TS23.273] describe the initial
authorization and download of user profile, including QoS profile. In
this specification we describe how end to end QoS may be
established: spanning the access domain (Wi-Fi access network) and
the PMIPv6 mobility domain between the MAG and the LMA. A key
question from an end to end QoS standpoint is how QoS policies on the
Wi-Fi access link is mapped to QoS in the PMIPv6 mobility domain and
further to 3GPP QoS policies for per user/per flow.
[PMIP-QoS] defines a QoS option to enable QoS in the PMIPv6 mobility
domain. The sub-options defined in the QoS option are mapped into
corresponding parameters in the 3GPP specified QoS parameters. [PMIP-
QoS] does not explicitly describe how the QoS signaling and QoS sub-
options map into corresponding signaling and parameters in the Wi-Fi
access network. This mapping is the focus of this document. The key
distinction between [PMIP-QoS] and this document is that this focuses
on the end-to-end flow (spanning 802.11 access and PMIPv6 domain)
while [PMIP-QoS] focuses on the QoS within the PMIPv6 mobility
domain. This document provides a systematic way to map to the various
QoS parameters available in initial authorization, as well as setup
of new sessions (such as a voice/video call). The mapping
recommendations allow for proper provisioning and consistent
interpretation between the various QoS parameters provided by PMIP
QoS, 3GPP and 802.11.
The rest of the document is organized as follows. Chapter 2 provides
an overview of the QoS mechanisms in 3GPP mobile networks and 802.11
networks. Chapter 3 describes different ways how end to end QoS with
Wi-Fi admission control is achieved. Chapter 4 describes how end to
end QoS without admission control is achieved.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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1.2. Definitions
Guaranteed Bit Rate (GBR)
GBR in 3GPP mobile network defines the guaranteed (reserved) bit
rate resources of service data flow on a connection (bearer)
[TS23.203].
Aggregate Maximum Bit Rate (AMBR)
AMBR represents the total bandwidth that all flows of a user is
allowed.
Allocation Retention Priority (ARP)
ARP is used in the mobile network to determine the order in which
resources for a flow may be preempted during severe congestion or
other resource limitation. ARP of 1 is the highest priority while
15 is the lowest [TS23.203].
Mean Data Rate
In WMM, Mean Data Rate specifies the average data rate in bits
per second. The Mean Data Rate does not include the MAC and PHY
overheads [WMM 1.2.0].
1.3. Abbreviations
3GPP Third Generation Partnership Project
AAA Authentication Authorization Accounting
AMBR Aggregate Maximum Bit Rate
ARP Allocation and Retention Priority
AP Access Point
DSCP Differentiated Services Code Point
EPC Enhanced Packet Core
GBR Guaranteed Bit Rate
MAG Mobility Access Gateway
MBR Maximum Bit Rate
MN Mobile Node
PDN-GW Packet Data Network Gateway
QCI QoS Class Indicator
QoS Quality of Service
Tspec Traffic Conditioning Spec
WLC Wireless Controller
2. Background
2.1. QoS in 3GPP based Networks
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3GPP has standardized QoS for EPC (Enhanced Packet Core) from Release
8 [TS 23.107]. 3GPP QoS policy configuration defines access agnostic
QoS parameters that can be used to provide service differentiation in
multi vendor and operator deployments. The concept of a bearer is
used as the basic construct for which the same QoS treatment is
applied for uplink and downlink packet flows between the MN (host)
and gateway [TS23.402]. A bearer may have more than one packet filter
associated and this is called a Traffic Flow Template (TFT). The IP
five tuple (IP source address, port, IP destination, port, protocol)
identifies a flow.
The access agnostic QoS parameters associated with each bearer are
QCI (QoS Class Identifier), ARP (Allocation and Retention Priority),
MBR (Maximum Bit Rate) and optionally GBR (Guaranteed Bit Rate). QCI
is a scalar that defines packet forwarding criteria in the network.
Mapping of QCI values to DSCP is well understood and GSMA has defined
standard means of mapping between these scalars [GSMA-IR34].
In a 3GPP radio network, priority and packet delay budget in QCI
determines the policy used for rate-shaping, scheduling and queue
management. The ARP is used to determine if a connection session
request should be allowed (e.g. insufficient radio resource) and the
order in which flows should be pre-empted in case of severe
congestion.
An MN may have more than one IP addresses associated with the same
hardware (MAC) address corresponding to each of the networks than it
is attached to. This corresponds to more than one PMIP mobility
session for which QoS is provisioned in the WLC.
2.2. QoS in PMIPv6 Mobility domain
[PMIP-QoS] defines a mobility option that can be used by the mobility
entities in the Proxy Mobile IPv6 domain to exchange Quality of
Service parameters associated with a subscriber's IP flows. Using the
QoS option, the local mobility anchor and the mobile access gateway
can exchange available QoS attributes and associated values. This
enables QoS policing and labeling of packets to enforce QoS
differentiation on the path between the local mobility anchor and the
mobile access gateway.
2.3. QoS in IEEE 802.11 based Networks
IEEE 802.11-2012 [802.11-2012] provides an enhancement of the MAC
layer in WiFi networks to support QoS--EDCA (Enhanced Distributed
Channel Access). EDCA uses a contention based channel access method.
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The EDCA mechanism provides differentiated, distributed access using
eight different UPs (User Priorities). EDCA also defines four access
categories (AC) that provide support for the delivery of traffic. In
EDCA, the random back-off timer and arbitration inter-frame space is
adjusted according to the QoS priority. Frames with higher priority
AC have shorter random back-off timers and arbitration inter-frame
spaces. Thus, there is a better chance for higher priority frames to
be transmitted. The Wi-Fi Alliance has created a specification
referred to as WMM (Wi-Fi Multimedia) based on above.
In addition to the above, QoS can also be provided using admission
control. The MN uses ADDTS (Add Traffic Specs) to setup a traffic
stream between itself and the AP, and DELTS to delete that stream. In
WMM [WMM 1.2.0], the AP advertises if admission control is mandatory
for an access class. Admission control for best effort or background
access classes is not recommended. The Wi-Fi Alliance has created a
specification referred to as WMM-AC (Wi-Fi Multimedia Admission
Control) based on the above.
3. End-to-End QoS with Admission Control
This section outlines a few use cases to illustrate how the
parameters and mapping in section 4 are applied. These cases are not
expected to be exhaustive.
There are two main types of interaction possible to provision QoS -
one is where the UE initiates the QoS request and the network
provisions the resources. The second is where the network provisions
resources as a result of some out of band signaling (like application
signaling). In this scenario, if the MN supports 802.11aa (TCLAS),
the network can push the QoS configuration to the MN. If the MN only
supports WMM QoS, then MN requests for QoS for the WiFi segment and
the MAG provisions based on QoS already provisioned for the MN.
3.1. Case A: MN Initiated QoS Signaling
When an MN sets up a connection that requires admission control in
the WiFi network, the level of QoS for the connection needs to be set
up. When the MN is configured (e.g. in SIM, subscription) to start
the QoS signaling, it sends an ADDTS request indicating the QoS
required for the connection. The AP/WLC (MAG) obtains the
corresponding level of QoS to be granted to the flow by sending a
PMIPv6 PBU message with QoS options to the LMA. Details of the setup
are described below.
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+--------+
+----+ | AP/WLC | +-------+
| MN | | (MAG) | | LMA |
+-+--+ +---+----+ +---+---+
| | |
/*************************************************************/
/* [0] connection setup to mobile network */
/*************************************************************/
| | |
|[1] ADDTS(TSPEC) | |
|-------------------->| |
| | PBU(QoS options)[2] |
| |---------------------->| Policy request
| | |--------------->
| | |Policy response
| | |<---------------
| | PBA (QoS option) [3] |
|[4]ADDTS Response |<----------------------|
| (TSPEC) | |
|<--------------------| |
| | |
Figure 1: MN initiated QoS setup
[0] The MN starts signaling to setup the connection. In mobile
networks, these are not default connections that are setup
initially. Default connections are best effort and do not need
explicit admission control with ADDTS.
[1] If the MN and network support 802.11aa and the MN is configured
to start QoS signaling, the MN sends an ADDTS request specifying
the QoS requested for the traffic stream including TSPEC element
with connection setup identifier.
[2] The MAG (AP/WLC) identifies the PMIP based on the connection
identifier and sends a PBU with QoS options requested.
[3] The LMA responds with the authorized QoS for the connection.
[4] The AP/WLC (MAG) provisions the corresponding QoS and replies
with ADDTS Response containing authorized QoS in TSPEC.
3.2. Case B: Network Initiated QoS Signaling (802.11aa based)
When an MN has connections or flows that require admission control,
the mobile network may provision correspond QoS in the MAG. This use
case illustrates how an MN and WiFi network that supports 802.11aa
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can provision QoS to the MN. In this case, the network is configured
to start the QoS signaling, it sends an ADDTS request indicating the
QoS required for the connection.
+--------+
+----+ | AP/WLC | +-------+
| MN | | (MAG) | | LMA |
+-+--+ +---+----+ +---+---+
| | |
| | |
/*************************************************************/
/* [0] connection setup to mobile network */
/*************************************************************/
| | | Policy update
| |UPN(update session)[2] |<---------------
| |<----------------------| [1]
| | PBU(QoS option) [3] |
| |---------------------->|
| | PBA (QoS option)[4] |
| ADDTS Reserve Req |<----------------------|
| (TCLAS/app id) [5] | |
|<--------------------| |
| ADDTS Reserve Response[6] |
|-------------------->| |
| | |
Figure 2: Network initiated QoS setup with 802.1aa
[0] The MN starts signaling to setup the connection. In mobile
networks, these are not default connections that are setup
initially. Default connections are best effort and do not need
explicit admission control with ADDTS.
[1] The LMA gets a QoS policy update for an existing connection.
[2] LMA sends a PMIP UPN (Update Notification) message to the MAG
requesting it to update session parameters.
[3] The MAG (AP/WLC) replies to UPN with a PBU including QoS
options.
[4] The LMA responds with the authorized QoS for the connection.
[5] If the MN and network support 802.11aa, the AP/WLC (MAG) sends
an ADDTS Reserve Request specifying the QoS reserved for the
traffic stream including TSPEC and TCLAS element with the
connection identifier (from PMIP).
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[6] The MN notes the QoS reserved in the network and replies with
ADDTS Reserve Response.
3.3. Case C: Hybrid (Network Initiated for PMIPv6 and MN initiated for
Wi-Fi)
This example outlines a scenario where an MN attaches to the WiFi and
then obtains services in the mobile network. When the MN attaches,
PMIP signaling between the MAG and LMA establishes mobile connection
and related QoS. Subsequently, the MN starts an application that
requires dedicated bandwidth resources and signals that using
TSPEC/ADDTS request. The details of this sequence are described
below.
+--------+
+----+ | AP/WLC | +-------+
| MN | | (MAG) | | LMA |
+-+--+ +---+----+ +---+---+
| | |
| | |
/*************************************************************/
/* [0] connection setup to mobile network */
/*************************************************************/
| | | Policy update
| |UPN(update session)[2] |<---------------
| |<----------------------| [1]
| | PBU(QoS option) [3] |
| |---------------------->|
| | PBA (QoS option)[4] |
| |<----------------------|
+-------------+ | |
|upper layer | | |
|notification | | |
+-+-+-+-+-+-+-+ | |
|ADDTS Request(TSPEC)[5] |
|-------------------->| |
| ADDTS Response [6] | |
|<--------------------| |
| | |
Figure 3: Network initiated QoS setup with WMM
[0] The MN starts signaling to setup the connection. In mobile
networks, these are not default connections that are setup
initially. Default connections are best effort and do not need
explicit admission control with ADDTS.
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[1] The LMA gets a QoS policy update for an existing connection.
[2] LMA sends a PMIP UPN (Update Notification) message to the MAG
requesting it to update session parameters.
[3] The MAG (AP/WLC) replies to UPN with a PBU including QoS
options.
[4] The LMA responds with the authorized QoS for the connection.
Since the MAG or MN does not support 802.11aa, the MAG updates
QoS profile of MN and waits for request from MN.
[5] When the MN receives upper layer signaling (e.g. SDP) indicating
acceptance of codec or other media parameters, the MN requests
for corresponding QoS in TSPEC of ADDTS Request.
[6] When the(AP/WLC (MAG) receives the ADDTS Request from MN, it
checks the QoS profile for the MN to see if the additional QoS
requested for the stream is consistent with the QoS profile
stored for the MN. The AP/WLC then responds with ADDTS Response.
3.4. Mapping of Connection Parameters
This section outlines the handling of QoS connection (session)
parameters between WiFi 802.11 and PMIP QoS.
Connection Mapping:
802.11 QoS in TSPEC is used to reserve QoS for a traffic stream
(MN MAC, TS(Traffic Stream) id). The QoS reservation is for
802.11 frames and here is no IP prefix/flow associated during
this reservation. The AP/WLC evaluates this request against
policy installed using PMIP QoS. When PMIP QoS policy is
installed in AP/WLC, the TSPEC request is granted if the MN
(identified by MAC) is authorized. The AP/WLC may police
subsequent flows with {MAC, TS, 802.1D, IP prefix} to match QoS
policy installed by PMIP QoS for {IP prefix, DSCP}.
QoS Class:
802.11 QoS Access Class (AC_VO, AC_VI) requests corresponds to
DSCP in PMIP QoS setup. Table 1 (section 4.1) below shows the
complete mapping.
Bandwidth:
For flows with reservation, the 802.11 Mean Data Rate should be
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equal to (or less than) Guaranteed Bit Rate (GBR). If the MN
requests Mean Data Rate in ADDTS greater than GBR, then AP/WLC
should deny the request in ADDTS Response.
For flows with no reservation, the bandwidth should not exceed
MBR (Maximum Bit Rate). If such a flow is offloaded at AP/WLC,
the policy obtained during authorization is used.
The total bandwidth used by all flows of an MN should not exceed
AMBR (Aggregate Maximum Bit Rate).
Preemption Priority:
Mobile networks configure ARP (Allocation Retention Priority)
during authorization and in [PMIP QoS]. If there is limited
resource and multiple ADDTS requests, ARP should be used by the
AP/WLC to determine which requests to grant. ARP has a range 1
to 15 with 1 being the highest priority [TS23.203].
During severe congestion or partial failure, if the AP/WLC has
to preempt existing reservations, ARP may be used to determine
the order of preemption.
3.5. Service Guarantees in 802.11
The GBR - Guaranteed Bit Rate in mobile networks are used to request
and commit resources in the network for providing the bandwidth
requested. In WiFi networks, a random backoff timer based on the
access class only provides priority access to a shared medium. These
mappings and recommendations allow the AP to schedule resources in a
fair manner based on subscribed QoS and application request/policy
server interaction.
However, there are no guaranteed or committed resources in the WiFi
network - only prioritization that gives better opportunity for
frames to compete for a shared medium.
It should also be noted that unlike mobile networks which inform the
MN about QoS for established or modified connections (bearers), there
is no means for an MN in WiFi networks to find out the QoS that a
policy server requests to be granted. Thus, the application in MN
should make its determination to downgrade a request based on SDP and
media parameters to downgrade to a lower quality.
4. End-to-End QoS without Admission Control
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GSMA and IETF (RFC 4594) have defined mapping between DSCP and IEEE
802.11 UP (user Priority). The MAG could be pre-configured to use the
mapping from one of these specifications. Per MN connection
configuration may be setup at the AP/WLC based by PMIP QoS signaling
during connection setup. This is described in [PMIP QoS], section
3.5.
However, in many cases it may be beneficial to use a different set of
mapping and potentially different mappings for different users. For
example an operator may choose to provide only best effort service to
one subscriber class while providing more enhanced (AF or EF)
services to other subscriber classes. To enables such capabilities, a
QoS Service Attribute called QoS MAP Set is introduced. This is
modeled after an IEEE 802.11 element with the same name (see 8.4.2.97
in IEEE 802.11-2012).
The QoS Map Set attribute is used as follows. The LMA would send a
specific DSCP to UP mapping in the Proxy Binding Update. In cases
where the MAG is co-located with the AP, AP/MAG can ensure that
received packets from the mobile node have the the correct DSCP to UP
mapping(packets with inappropriate marking may be remarked).
Similarly, on the downstream, the QoS Map Set enables the MAG/AP to
determine the correct UP. This also ensures that a source ineligible
for higher grades of service (provided by higher priority UP bits)
cannot avail of such a service by marking the packets with DSCP
values (for example by marking the packets with EF and AF
codepoints). There is an additional benefit of providing the AP/MAG
with the QoS Map Set. For mobile nodes that support the IEEE 802.11
QoS Map Set capability, the AP can provide the corresponding QoS Map
Set information to the mobile node. This can ensure that the mobile
node uses the correct DSCP to UP marking.
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 1 2 3 4 5 6 7
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UP0 Range | UP1 Range | UP2 Range | UP3 Range |
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UP4 Range | UP5 Range | UP6 Range | UP7 Range |
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP Ex-0 | DSCP Ex-1 | DSCP Ex-3 ....
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+-++-+-+-+
Type: TBD Length: Length of the following data value in octets,
greater than or equal to 10.
The format of UP0,..,UP7 Range is as follows
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0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+
| DSCP Low Val | DSCP Hi Val |
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+
The format of the DSCP Exception field is as follows
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+
| DSCP Val | UP Value |
+=+-+-+-+-+=+-+-+-+-+-+-+-+-+-+-+
4.1. Default Values and Recommendations
The table below outlines a recommended mapping between 3GPP QCI,
and 802.11 Access Category (AC)/ 802.1D UP.
QCI DSCP 802.1D UP WMM 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 IMS 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 e-mail
Table 1: QoS Mapping between QCI/DSCP, 802.1D UP, WMM AC
The QoS mapping table above provides recommendations and default
mapping between DSCP provided in [PMIP QoS], WMM AC used for TSPEC
reservation, and 802.1D UP in 802.11 frames.
5. Security Considerations
This document describes mapping of 3GPP QoS profile and parameters to
IEEE 802.11 QoS parameters. No security concerns are expected as a
result of using this mapping.
6. IANA Considerations
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No IANA assignment of parameters are required in this document.
7. References
7.1. Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC1776] Crocker, S., "The Address is the Message", RFC 1776,
April 1 1995.
[TRUTHS] Callon, R., "The Twelve Networking Truths", RFC 1925,
April 1 1996.
7.2. Informative References
[EVILBIT] Bellovin, S., "The Security Flag in the IPv4 Header",
RFC 3514, April 1 2003.
[RFC5513] Farrel, A., "IANA Considerations for Three Letter
Acronyms", RFC 5513, April 1 2009.
[RFC5514] Vyncke, E., "IPv6 over Social Networks", RFC 5514, April 1
2009.
[PMIP-QoS] Liebsch, et al., "Quality of Service Option for Proxy
Mobile IPv6", draft-ietf-netext-pmip6-qos-00, June 2012.
[WMM 1.2.0] Wi-Fi Multimedia Technical Specification (with WMM-Power
Save and WMM-Admission Control) Version 1.2.0
[802.11aa] Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specification, Amendment 2: MAC Enhancements
for Robust Audio Video Streaming, IEEE 802.11aa-2012.
[802.11-2012] 802.11-2012 - 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
[GSMA-IR34]Inter-Service Provider Backbone Guidelines 5.0, 22
December 2010
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[RFC 2211] Wroclawski, J., "Specification of the Controlled Load
Quality of Service", RFC 2211, September 1997.
[RFC 2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212, September
1997.
[RFC 2216] Shenker, S., and J. Wroclawski, "Network Element QoS
Control Service Specification Template", RFC 2216,
September 1997.
[TS23.107] Quality of Service (QoS) Concept and Architecture, Release
10, 3GPP TS 23.107, V10.2.0 (2011-12).
[TS23.207] End-to-End Quality of Service (QoS) Concept and
Architecture, Release 10, 3GPP TS 23.207, V10.0.0 (2011-
03).
[TS23.402] Architecture Enhancements for non-3GPP accesses(Release
12), 3GPP TS 23.402, V12.2.0 (2013-09).
[TS23.203] Policy and Charging Control Architecture, Release 11, 3GPP
TS 23.203, V11.2.0 (2011-06).
[TS29.212] Policy and Charging Control over Gx/Sd Reference Point,
Release 11, 3GPP TS 29.212, V11.1.0 (2011-06).
[TS29.273] 3GPP EPS AAA interfaces(Release 12), 3GPP TS 29.273
v12.1.0 (2013-09)
Authors' Addresses
John Kaippallimalil
5340 Legacy Drive, Suite 175
Plano, Texas 75024
E-Mail: john.kaippallimalil@huawei.com
Rajesh Pazhyannur
170 West Tasman Drive
San Jose, CA 95134
E-Mail: rpazhyan@cisco.com
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Parviz Yegani
1194 North Mathilda Ave.
Sunnyvale, CA 94089-1206
E-Mail: pyegani@juniper.net
Appendix A: QoS Policy Architecture
The QoS architecture in this section provides a brief outline for
provisioning QoS in a consistent manner across the WiFi network,
backhaul and PMIP mobile network.
QoS information is available to AP/WLC when the MN attaches to the
WiFi network and authenticates. The authorization profile includes
QoS that the user/MN has subscribed to. When the MN attaches to the
network, the LMA returns the session parameters such as IP address
and may also include QoS profile as per [PMIP-QoS].
+-----------+ +-----------+
| AAA | | Policy |
+-----+-----+ +-----+-----+
| |
(Authorization) (Session)
| |
AP/WLC |(MAG) PDN-GW |(LMA)
+----+ +------|-----+ +------|-----+
| | | +----v---+ | PMIP-QoS | +----v---+ |
| | | |QoS-Pol <---------------| |QoS-Pol | |
| | | +---+----+ | | +---+----+ |
| MN | | | | ___ | | |
| | 801.11 | +---v----+ | ( ) +---v----+ |
| +-------------+ PEP +-+--( IP )-----+ PEP + |
| | | +--------+ | (Network ) | +--------+ |
+----+ +------------+ \ / +------------+
+---+
Figure 4: Architecture for provisioning QoS Policy on WiFi AP
Figure 4 provides an overview of the architecture in which QoS for an
MN is provisioned on the AP/WLC. MN QoS policy from initial
authorization and PMIP connection establishment is provisioned in the
AP/WLC QoS-Pol (logical function). AP/WLC PEP uses the policies for
handling QoS flows from an MN.
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Policy Server provisioning of Admission control for connections has
traditionally relied on information from Deep Packet Inspection (DPI)
or Application Level Gateways (ALG). DPIs and ALGs cannot however
determine the MNs subscribed bandwidth or QoS. The alternative is to
provision QoS policy for a user's connections and use subscribed
policy and PMIP QoS policy. When the AP/WLC has both the subscribed
QoS policy and policy parameters from PMIP QoS, the QoS parameters
obtained through PMIP reflect the policy that accounts for current
network conditions.
In mobile networks, default connections are not setup with a
bandwidth reservation and hence do not have a GBR (Guaranteed Bit
Rate) associated. However, the PDN-GW (LMA) polices the AMBR
(Aggregate Maximum Bandwidth Rate) - the maximum bit rate for all
flows to/from the MN. Thus, upstream traffic should be policed by
AP/WLC to not exceed the maximum prescribed in AMBR values. The
AP/WLC should also schedule traffic for these connections as
background or best effort (AC_BK, AC_BE) and the corresponding
802.1D
For voice, video and other applications that require reservation of
QoS resources, a dedicated PMIP connection is setup in mobile
networks and the PDN-GW (LMA) reserves resources as per GBR
(Guaranteed Bit Rate) for upstream and downstream. In this also, the
total bit rate of all flows to/from MN should not exceed the maximum
bit rates in AMBR (Aggregate Maximum Bit Rate). Upstream and
downstream traffic should be scheduled by MN and AP/WLC using ADDTS
(TSPEC) for voice or video (AC_VO, AC_VI). The MN should also include
the Mean Data Rate for the connection based on the requirements of
the application or negotiated codec. The AP/WLC grants resources
based on policy obtained over PMIP QoS. GBR values in PMIP QoS should
be used to derive Mean Data Rate as described in section 4.1. When
the MN completes the session, it may send DELTS to request release of
associated QoS resources.
If the MN connection is offloaded to the internet by the AP/WLC,
there is no corresponding PMIP session setup to the mobile network.
In this case, the AP/WLC may use AMBR obtained during authorization
if the MN has no other connections to the mobile network. If the MN
has other connections to the mobile network, he AP/WLC should limit
the maximum bit rate of all flows of the MN to AMBR obtained in PMIP
QoS.
When the network is congested and the AP/WLC cannot grant the QoS
requested by MN, the AP/WLC should refuse the ADDTS request and not
continue the PMIP QoS signaling request. The application in MN may
downgrade the codec and re-negotiate a new TSPEC/resource request
that the AP/WLC may grant. If the AP/WLC cannot handle committed
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connections due to network degradation or other partial failures, the
AP/WLC may use the ARP (Allocation Retention Priority) values of the
connection to gracefully release resources.
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