INTERNET-DRAFT John Kaippallimalil Intended Status: Informational Huawei Expires: October 23, 2013 April 21, 2013 Mapping PMIP Quality of Service in WiFi Network draft-kaippallimalil-netext-pmip-qos-wifi-02 Abstract This document proposes a model for configuring and mapping PMIP QoS parameters of a mobile network session to the corresponding connection at a WiFi Access Point. In congested network conditions, it is useful for an MN's flows to be policed and shaped at the WLC and WiFi AP to match bandwidth constraints or service priority of the user's subscription. Applying similar QoS management at the WiFi AP and WLC allows optimal use of network resources. Currently, the WiFi AP does not have information on the MNs subscribed bandwidth, or relative priority of its flows or services for per user QoS handling at the WiFi AP. This document provides a model for mapping PMIP QoS to corresponding 802.11e QoS parameters. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Kaippallimalil et al. Expires October 23, 2013 [Page 1] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . 4 2. QoS Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. QoS in Mobile Networks . . . . . . . . . . . . . . . . . . 4 2.2. QoS in WiFi Networks . . . . . . . . . . . . . . . . . . . 5 3. Connection Model . . . . . . . . . . . . . . . . . . . . . . . 5 4. Policy Provisioning Architecture . . . . . . . . . . . . . . . 7 5. QoS Configuration and Mapping . . . . . . . . . . . . . . . . . 8 5.1. PMIP - 802.11e QoS Configuration . . . . . . . . . . . . . 8 5.2. Mapping Recommendations and Default Values . . . . . . . . 9 6. Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 11 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 11 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 9.1. Normative References . . . . . . . . . . . . . . . . . . . 11 9.2. Informative References . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Kaippallimalil et al. Expires October 23, 2013 [Page 2] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 1. Introduction This document describes a means for the QoS profile of a PMIP session to be applied to QoS on the 802.11 connection segment of the MN (Mobile Node). A mobile network may dynamically provision QoS for its users attached via a WiFi access and PMIP backhaul. [PMIP-QoS] defines a mechanism by which QoS policy parameters in the mobile network are delivered from the LMA to the the WLC (MAG) using PMIP QoS extensions. [PMIP-QoS] further describes how the DSCP value for the PMIP session is mapped to corresponding 802.1p value that may be used by IP backhaul network or WiFi APs to prioritize IP flows of a host (MN). While [PMIP-QoS] defines how mobile network QoS can be applied to PMIP flows, the WiFi AP has to reflexively map QoS for IP flows. Based on the observed DSCP values in downstream packets of an IP flow, the WiFi AP provides the same level of QoS in the upstream direction. In addition, the WiFi AP may use the downstream DSCP values to determine the scheduling priority in the 802.11 network. Based on [PMIP-QoS], the WLC (MAG) can use DSCP priority as well as other parameters of the MN such as subscribed bandwidth and service priority to police IP flows of an MN. The WiFi AP on the other hand relies on DSCP priority for scheduling and policing IP flows of an MN since it does not have per subscriber policy information of an MN. In congested network conditions, it is not possible for the WiFi AP to differentiate between MNs that have premium subscriptions. In addition, it is possible that upstream flows from the WiFi AP are throttled by the WLC to match the bandwidth constraints or service priority. This can result in sub-optimal use of network resources. In order for the WiFi AP to differentiate on per flow and per user basis, it needs information on the MNs subscribed bandwidth and other policy information. This proposal aims to provide the WiFi AP with per MN QoS profile to allow more effective overall use of network resources - both WiFi radio and IP backhaul. The QoS parameters needed are available to the WLC during MN authorization and establishment of the PMIP session with QoS extensions. Since an MN may establish tunneled IP flows, direct IP connections or offloaded connections, the relationship of PMIP QoS to 802.11e QoS is explained. It is possible that an MN (with a single 802.11 interface) has more than one PMIP session. The QoS policy for the MN may be applied by the AP to schedule and control WiFi radio network resources and upstream user flows in the IP backhaul network. If per session QoS policy is not available, the AP may be provisioned to apply QoS based on the subscribed QoS values obtained during 3GPP user authorization. In order to provision QoS in the WiFi network, a consistent mapping Kaippallimalil et al. Expires October 23, 2013 [Page 3] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 of QoS parameters and values between 3GPP and 802.11e is needed. Recommendations to map 3GPP QCI to DSCP for mobility sessions are available in [PMIP-QoS]. This document adds the configuration of QoS per PMIP mobility session to a WiFi radio access. The rest of the document is organized as follows. Chapter 2 outlines the QoS mechanisms in 3GPP mobile networks and 802.11 networks. Chapter 3 provides an overview of the architecture in which QoS is provisioned on the WiFi AP. Chapters 4 and 5 describe the connection model in the access network and the QoS mapping itself. 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]. 1.2. Definitions 1.3. Abbreviations 3GPP Third Generation Partnership Project AAA Authentication Authorization Accounting 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. QoS Mechanisms 2.1. QoS in Mobile Networks 3GPP has standardized QoS for EPC (Enhanced Packet Core) from Release 8 [TS 23.107]. 3GPP QoS policy configuration defines access agnostic Kaippallimalil et al. Expires October 23, 2013 [Page 4] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 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 [TS23.401]. 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]. 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 WiFi Networks 802.11e [802.11e] defined by IEEE provides an enhancement of the MAC layer in WiFi networks to support QoS. Basic 802.11 WiFi uses CSMA and collision avoidance to provide best effort access to the medium. 802.11e defines a Hybrid Coordination Function (HCF) that provides a priority based access and also admission control based access. HCF contention based channel access provides prioritized access to the 802.11 medium. Four access categories (AC) are defined based on traffic type. Each arriving frame is mapped into one of four FIFO queues corresponding to different user priority (UP) values. The highest priority frame is transmitted when access is obtained in a contention window. Access categories and their mapping to 802.1D user priorities is provided [802.11e]. HCF controlled channel access uses a central coordinator to provide contention free access to the medium based on admission control. The HCCA (HCF Controlled Channel Access) based scheduling can use configured policies to grant exclusive access to a QSTA (user) for limited contention free slots. 3. Connection Model Kaippallimalil et al. Expires October 23, 2013 [Page 5] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 MNs that attach to a mobile network via a WiF AP and WLC are provisioned with IP addresses corresponding to each PMIP session. Each of the IP sessions at MN has QoS policies associated to it. This section outlines the connection model in detail and QoS mapping on the WiFi AP. WiFi AP WLC(MAG) +----------+ +-------------+ |+--------+| | +---------+ | +---+ || PEP || | + PEP + | |MN | |+--------+| | +---------+ | | 1 ===========================[conn-1]================[PMIP-1] +---+ | | | | +---+ | | | | |MN +--------------------------[conn2a]---------=======[PMIP-2] | 2 +--------------------------[conn2b]--------- | +---+ +----------+ +------|------+ | V [offload path] Figure 1: MN Connection model An MN may establish a session to the mobile network or may have a session that is offloaded to the internet from the WLC. Figure 2 shows MN1 and MN2 attached to the WLC via a WiFi AP. An MN may have a tunneled connection to the mobile network (MN1, conn-1, PMIP-1), (MN2, conn2a, PMIP-2) and an IP connection that is offloaded at the WLC (MN2, conn2b, offload). The specification for IP tunnel/connection between MN and WLC are out of the scope of this document. For an MN - WLC connection segment with IP address configured via PMIP (e.g. MN2 conn2a), the corresponding PMIP QoS would be applicable to MN flows with this IP address. For connection segment that is offloaded at WLC, the IP address is configured by the WLC. As in the case of PMIP connections, QoS is provisioned for MN flows with this IP address In both cases - PMIP session related connection segment, or offload connection segment - the WiFi AP gets QoS traffic filters and configuration from the WLC. The QoS profile would be identified by the IP address for the PMIP / offload session. Kaippallimalil et al. Expires October 23, 2013 [Page 6] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 4. Policy Provisioning Architecture This section describes the architecture in which the PMIP QoS configuration of MN sessions is applied to the corresponding traffic flows in the WiFi Access Point. Following MN attach to the WiFi network and authentication with the mobile network, the WLC gets QoS parameters and other policy for the authorized MN. When the PMIP connection is created, the PDN-GW returns QoS policy using [PMIP-QoS] extensions. In [PMIP-QoS], the Access Point (AP) is not directly provisioned with QoS for an MN connection. As a result, the AP is only able to prioritize flows based on observed downlink DSCP values. Additionally, the AP does not know the maximum bandwidth of a subscriber or flow to be applied on the WiFi radio network. This can result in sub-optimal utilization of scarce WiFi network resources, and of the overall access network. This solution provides a description to provision the AP with QoS policy associated to an MN. The paragraphs that follow outline the overall architecture and subsequent chapters provide details on QoS parameters provisioned in the AP. +-----+ | AAA | +--+--+ | |Auth | WiFi AP WLC(MAG)| +----------+ +------|------+ |+--------+| QoS | +----v----+ | PMIP-QoS +------+ ||QoS-Ctrl<------------+QoS-Ctrl <------------+PDN-GW+ |+---+----+| Policy | +----+----+ | +--+---+ | | | | | | | 801.11 |+---v----+| _____ | +----V----+ | ________ | [MN]--------+ PEP +--/ IP )---+ PEP +----/ IP ) | |+--------+| Network | +---------+ | | Network|-+ +----------+ ( / +-------------+ ( / ----- .------. Figure 2: Architecture for provisioning QoS Policy on WiFi AP Figure 1 provides an overview of the architecture in which QoS for an MN is provisioned on the AP. MN QoS policy from initial session authorization and PMIP connection establishment is provisioned in the WLC QoS-Ctrl (logical function). QoS-Ctrl in WLC installs QoS to the Kaippallimalil et al. Expires October 23, 2013 [Page 7] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 WLC PEP as described in [PMIP-QoS]. The WLC translates 3GPP QoS policy to equivalent parameters for IP flows and applies them for scheduling and policing. In this solution, the WLC sends policy information for an MNs PMIP sessions to the WiFi AP. The protocols used to exchange QoS parameters between the WLC and AP are not discussed in this document. The AP can use the received QoS policy configuration and applies them to upstream and downstream forwarding of data packets in the WiFi radio network. The AP can also apply these QoS policies for upstream user IP flows to the WLC. An MN may have more than one PMIP session at any given time. Each of these PMIP sessions can have different policy parameters. The WLC provides the WiFi AP with a policy corresponding to each of these PMIP sessions. Since each PMIP session configures an IP address for the MN, the policy can be sent per IP address of MN that corresponds to the PMIP session. This model is described further in the following chapter. If the MN connection at WLC is offloaded to the internet, there is no PMIP session setup to the mobile network. In this case, the WLC should use the subscriber policy obtained during authorization. The WiFi AP is provisioned as for other sessions. The WLC provides the WiFi AP with QoS parameters for the MN IP address used for the offload connection. 5. QoS Configuration and Mapping 5.1. PMIP - 802.11e QoS Configuration The WiFi Access Point (AP) gets QoS configuration per IP session from the WLC. The QoS information per IP session provided to the AP includes: - Hardware (MAC) address of host for which PMIP session is established. - IP prefix or address of PMIP mobility session. - IP port address (used for NATed connections). - DSCP. Diffserv PHB value of PMIP QoS for the mobility session. - QCI. The WLC provides the 3GPP QCI value if available, for example, from authorization profile of APN (i.e. subscribed values per established PMIP mobility session). - ARP (Allocation and Retention Priority). This value is obtained from the PMIP QoS for the mobility session. It determines the priority of a flow (1 has highest priority). - MBR (Maximum Bit Rate) for mobility session uplink and downlink. This should not exceed the AMBR (Aggregate MBR) of the Kaippallimalil et al. Expires October 23, 2013 [Page 8] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 subscription. - GBR (Guaranteed Bit Rate) for mobility session uplink and downlink, if required. The WiFi AP uses the above QoS configuration to implement classification, admission control and forwarding of MN flows. The WiFi AP maps DSCP (or QCI) to 802.11e AC (Access Categories) for each IP session / hardware (MAC) address of the host (3GPP user). The mapping from DSCP or QCI to 802.11e AC is shown in table in chapter 4 below. In the WiFi radio network, the AP uses 802.11e AC values for contention (HCF) based forwarding based on priority. The AP schedules downstream flows in the WiFi radio network and for upstream IP backhaul to the WLC. For contention free scheduling, the WiFi AP additionally uses the QoS configuration per user to admit flows based on 802.11e ADDTS (ADD TSpec) requests from the host (3GPP user). The WiFi AP may drop packet that fall outside the configured MBR and GBR. In case of severe radio congestion, the WiFi AP can use ARP in addition to DSCP drop precedence to determine the flows to be dropped. 5.2. Mapping Recommendations and Default Values The table below outlines a recommended mapping between 3GPP QCI, and 802.11e Access Category (AC) priorities. QCI packet delay budget and packet error loss rate may be used by the WiFi access point in scheduling contention free access when HCCA scheduling is used. QCI DSCP 802.11e AC Example 3GPP service ------------------------------------------------------------- 1 EF 3 AC_VO conversational voice 2 EF 3 AC_VO conversational video 3 EF 3 AC_VO real-time gaming 4 AF41 2 AC_VI buffered streaming 5 AF31 2 AC_VI IMS signaling 6 AF31 2 AC_VI buffered streaming 7 AF21 0 AC_BE interactive gaming 8 AF11 0 AC_BE web access 9 BE 1 AC_BK e-mail Table 1: QoS Mapping between QCI, WMM, 802.11e AC Kaippallimalil et al. Expires October 23, 2013 [Page 9] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 6. Next Steps This document has described a basic model for mapping PMIP QoS parameters to 802.11e parameters. However, there are a few questions that need to be explored further. The protocol between WLC and AP is not discussed in this document. There needs to be work to determine the protocol specification if it is desired that WLC and AP should interwork for QoS capability. Another aspect is this draft does not describe multiple PDN connections per MN in much detail. This is work in progress in 3GPP and the results should be compatible with the model in this draft. RTC Web impact to 3GPP networks is currently being studied. There are several technical options being considered by 3GPP at this time. If the chosen solution requires more than one type of DSCP/QoS to be configured per PMIP session/IP connection segment - for example if audio and video flows use the same IP session - then this capability is required for WLC - AP configuration also. Finally, the QoS values listed in the table in chapter 5 needs to be aligned with [PMIP-QoS] and GSMA. Kaippallimalil et al. Expires October 23, 2013 [Page 10] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 7. Security Considerations This document describes mapping of 3GPP QoS profile and parameters to IEEE 802.11e parameters. No security concerns are expected as a result of using this mapping. 8. IANA Considerations No IANA assignment of parameters are required in this document. 9. References 9.1. 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. 9.2. 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. [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 Kaippallimalil et al. Expires October 23, 2013 [Page 11] INTERNET DRAFT Mapping QoS from PMIP to 802.11e April 21, 2013 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). [TS23.401] General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E- UTRAN) access (Release 11), 3GPP TS 23.401, V11.2.0 (2012- 06). [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). [802.11e] IEEE, "IEEE part 11: Wireless LAN Medium Access Control(MAC) and Physical Layer (PHY) specifications. Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements" 802.11e-2005, 22 September 2005. [GSMA-IR34]Inter-Service Provider Backbone Guidelines 5.0, 22 December 2010 Authors' Addresses John Kaippallimalil 5340 Legacy Drive, Suite 175 Plano Texas 75024 E-Mail: john.kaippallimalil@huawei.com Kaippallimalil et al. Expires October 23, 2013 [Page 12]