RFC 7222
Quality-of-Service Option for Proxy Mobile IPv6
Pages: 58
Proposed Standard
Proposed Standard
Part 1 of 3 – Pages 1 to 12
Internet Engineering Task Force (IETF) M. Liebsch Request for Comments: 7222 NEC Category: Standards Track P. Seite ISSN: 2070-1721 Orange H. Yokota KDDI Lab J. Korhonen Broadcom Communications S. Gundavelli Cisco May 2014 Quality-of-Service Option for Proxy Mobile IPv6Abstract
This specification defines a new mobility option, the Quality-of- Service (QoS) option, for Proxy Mobile IPv6. This option can be used by the local mobility anchor and the mobile access gateway for negotiating Quality-of-Service parameters for a mobile node's IP flows. The negotiated QoS parameters can be used for QoS policing and marking of packets to enforce QoS differentiation on the path between the local mobility anchor and the mobile access gateway. Furthermore, making QoS parameters available on the mobile access gateway enables mapping of these parameters to QoS rules that are specific to the access technology and allows those rules to be enforced on the access network using access-technology-specific approaches. Status of This Memo This is an Internet Standards Track document. 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). Further information on Internet Standards is available in 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/rfc7222.
Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.Table of Contents
1. Introduction ....................................................3 2. Conventions and Terminology .....................................4 2.1. Conventions ................................................4 2.2. Terminology ................................................5 3. Overview of QoS Support in Proxy Mobile IPv6 ....................7 3.1. Quality-of-Service Option -- Usage Examples ................9 3.2. Quality-of-Service Attributes -- Usage Examples ...........11 4. Protocol Messaging Extensions ..................................12 4.1. Quality-of-Service Option .................................12 4.2. Quality-of-Service Attributes .............................14 4.2.1. Per-Mobile-Node Aggregate Maximum Downlink Bit Rate ...........................................16 4.2.2. Per-Mobile-Node Aggregate Maximum Uplink Bit Rate ..17 4.2.3. Per-Mobility-Session Aggregate Maximum Downlink Bit Rate ..................................18 4.2.4. Per-Mobility-Session Aggregate Maximum Uplink Bit Rate ....................................20 4.2.5. Allocation and Retention Priority ..................22 4.2.6. Aggregate Maximum Downlink Bit Rate ................23 4.2.7. Aggregate Maximum Uplink Bit Rate ..................25 4.2.8. Guaranteed Downlink Bit Rate .......................26 4.2.9. Guaranteed Uplink Bit Rate .........................27 4.2.10. QoS Traffic Selector ..............................28 4.2.11. QoS Vendor-Specific Attribute .....................29 4.3. New Status Code for Proxy Binding Acknowledgement .........30 4.4. New Notification Reason for Update Notification Message ...30 4.5. New Status Code for Update Notification Acknowledgement Message ...................................31 5. Protocol Considerations ........................................31 5.1. Local Mobility Anchor Considerations ......................31 5.2. Mobile Access Gateway Considerations ......................35
6. QoS Services in Integrated WLAN-3GPP Networks ..................39 6.1. Technical Scope and Procedure .............................39 6.2. Relevant QoS Attributes ...................................41 7. IANA Considerations ............................................42 8. Security Considerations ........................................44 9. Acknowledgements ...............................................44 10. References ....................................................44 10.1. Normative References .....................................44 10.2. Informative References ...................................45 Appendix A. Information When Implementing 3GPP QoS in IP Transport Network ....................................47 A.1. Mapping Tables ............................................47 A.2. Use Cases and Protocol Operations .........................48 A.2.1. Handover of Existing QoS Rules ........................48 A.2.2. Establishment of QoS Rules ............................50 A.2.3. Dynamic Update to QoS Policy ..........................52 Appendix B. Information When Implementing PMIP-Based QoS Support with IEEE 802.11e ....................................53 Appendix C. Information When Implementing with a Broadband Network Gateway ......................................571. Introduction
Mobile operators deploy Proxy Mobile IPv6 (PMIPv6) [RFC5213] to enable network-based mobility management for mobile nodes (MNs). Users can access IP-based services from their mobile device by using various radio access technologies. The currently supported mobile standards have adequate support for QoS-based service differentiation for subscriber traffic in cellular radio access networks. QoS policies are typically controlled by a policy control function, whereas the policies are enforced by one or more gateways in the infrastructure, such as the local mobility anchor (LMA) and the mobile access gateway (MAG), as well as by access network elements. Policy control and in-band QoS differentiation for access to the mobile operator network through alternative non-cellular access technologies are not supported in the currently specified standards. Although support for IP session handovers and IP flow mobility across access technologies already exists in cellular standards [TS23.402], QoS policy handovers across access technologies has not received much attention so far. Based on the deployment trends, Wireless LAN (WLAN) can be considered as the dominant alternative access technology to complement cellular radio access. Since the 802.11e extension [IEEE802.11e-2005] provides QoS extensions to WLAN, it is beneficial to apply QoS policies to WLAN access, which enables QoS classification of downlink as well as uplink traffic between a mobile node and its local
mobility anchor. For realizing this capability, this specification
identifies three functional operations:
(a) Maintaining QoS classification during a handover between
cellular radio access and WLAN access by means of establishing QoS
policies in the handover target access network,
(b) mapping of QoS classes and associated policies between
different access systems, and
(c) establishment of QoS policies for new data sessions/flows,
which are initiated while using WLAN access.
This document specifies an extension to the PMIPv6 protocol [RFC5213]
to establish QoS policies for a mobile node's data traffic on the
local mobility anchor and the mobile access gateway. QoS policies
are conveyed in-band with PMIPv6 signaling using the specified QoS
option and are enforced on the local mobility anchor for downlink
traffic and on the mobile access gateway and its access network for
the uplink traffic. The specified option allows association between
IP session classification characteristics, such as a Differentiated
Services Code Point (DSCP) [RFC2474], and the expected QoS class for
the IP session. This document specifies fundamental QoS attributes
that apply on a per-mobile-node, per-mobility-session, or per-flow
basis. The specified attributes are not specific to any access
technology but are compatible with the Third Generation Partnership
Project (3GPP) and IEEE 802.11 Wireless LAN QoS specifications
[IEEE802.11-2012].
Additional QoS attributes can be specified and used with the QoS
option, e.g., to represent more specific descriptions of latency
constraints or jitter bounds. The specification of such additional
QoS attributes as well as the handling of QoS policies between the
mobile access gateway and the access network are out of the scope of
this specification.
2. Conventions and Terminology
2.1. Conventions
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].
2.2. Terminology
All the mobility-related terms used in this document are to be interpreted as defined in the Proxy Mobile IPv6 specifications [RFC5213], [RFC5844], and [RFC7077]. Additionally, this document uses the following abbreviations: Aggregate Maximum Bit Rate (AMBR) AMBR defines the upper limit on the bit rate that can be provided by the network for a set of IP flows. IP packets within the flows exceeding the AMBR limit may be discarded by the rate-shaping function where the AMBR parameter is enforced. Variants of the "AMBR" term can be defined by restricting the target set of IP flows on which the AMBR is applied to a mobile node, mobility session, or flow direction. For example, Per-Mobile-Node Aggregate Maximum Downlink Bit Rate, Per-Mobile-Node Aggregate Maximum Uplink Bit Rate, Per-Mobility-Session Aggregate Maximum Downlink Bit Rate, and Per-Mobility-Session Aggregate Maximum Uplink Bit Rate are used in this document. Allocation and Retention Priority (AARP) AARP is used in congestion situations when there are insufficient resources for meeting all Service Requests. It is used primarily by the Admission Control function to determine whether a particular Service Request must be rejected due to lack of resources or honored by preempting an existing low-priority service. Differentiated Services Code Point (DSCP) In the Differentiated Services Architecture [RFC2474], packets are classified and marked to receive a particular per-hop forwarding behavior on nodes along their path based on the marking present on the packet. This marking on IPv4 and IPv6 packets that defines a specific per-hop behavior is known as DSCP. Refer to [RFC2474], [RFC2475], [RFC4594], and [RFC2983] for a complete explanation. Downlink (DL) Traffic The mobile node's IP packets that the mobile access gateway receives from the local mobility anchor are referred to as the Downlink traffic. The "Downlink" term used in the QoS attribute definition is always from the reference point of the mobile node, and it implies traffic heading towards the mobile node.
Guaranteed Bit Rate (GBR)
GBR denotes the assured bit rate that will be provided by the
network for a set of IP flows. It is assumed that the network
reserves the resources for supporting the GBR parameter. Variants
of the "GBR" term can be defined by limiting the scope of the
target IP flows on which the GBR is applied to a mobile node,
mobility session, or flow direction. For example, Guaranteed
Downlink Bit Rate and Guaranteed Uplink Bit Rate are used in this
document.
Mobility Session
The term "mobility session" is defined in [RFC5213]. It refers to
the creation or existence of state associated with the mobile
node's mobility binding on the local mobility anchor and on the
mobile access gateway.
QoS Service Request
A QoS Service Request is a set of QoS parameters that are defined
to be enforced on one or more mobile node's IP flows. The
parameters at the minimum include a DSCP marking and additionally
may include Guaranteed Bit Rate or Aggregate Maximum Bit Rate.
The Quality-of-Service option defined in this document represents
a QoS Service Request.
Service Identifier
In some mobility architectures, multiple services within the same
mobility service subscription are offered to a mobile node. Each
of those services provide a specific service (for example,
Internet Service and Voice Over IP Service) and has an identifier
called "Service Identifier". 3GPP APN (Access Point Name) is an
example of a Service Identifier. Refer to [RFC5149] for the
definition of the Service Identifier and the mobility option used
for carrying the Service Identifier.
Uplink (UL) Traffic
The mobile node's IP packets that the mobile access gateway
forwards to the local mobility anchor are referred to as the
Uplink traffic. The "Uplink" term used in the QoS attribute
definitions is based on the reference point of the mobile node,
and it implies traffic originating from the mobile node.
3. Overview of QoS Support in Proxy Mobile IPv6
The Quality-of-Service support in Proxy Mobile IPv6 specified in this document is based on the Differentiated Services Architecture ([RFC2474] and [RFC2475]). The access and the home network in the Proxy Mobile IPv6 domain are assumed to be DiffServ-enabled, with every network node in the forwarding path for the mobile node's IP traffic being DiffServ-compliant. The per-hop behavior for providing differential treatment based on the DiffServ marking in the packet is assumed to be supported in the Proxy Mobile IPv6 domain. The local mobility anchor in the home network and the mobile access gateway in the access network define the network boundary between the access and the home network. As the tunnel entry and exit points for the mobile node's IP traffic, these entities are the logical choice for being chosen as the QoS enforcement points. The basic QoS functions such as marking, metering, policing, and rate-shaping on the mobile node's IP flows can be enforced at these nodes. The local mobility anchor and the mobile access gateway can negotiate the Quality-of-Service parameters for a mobile node's IP flows based on the signaling extensions defined in this document. The QoS services that can be enabled for a mobile node are for meeting both the quantitative performance requirements (such as Guaranteed Bit Rate) as well as for realizing relative performance treatment by way of class-based differentiation. The subscriber's policy and the charging profile (for example, [TS22.115]) are key considerations for the mobility entities in the QoS service negotiation. The decision on the type of QoS services that are to be enabled for a mobile node is based on the subscriber profile and based on available network resources. The negotiated QoS parameters are used for providing QoS differentiation on the path between the local mobility anchor and the mobile access gateway. The signaling related to QoS services is strictly between the mobility entities and does not result in per- flow state or signaling to any other node in the network.
+=======+ | MN-1 | +=======+ | | | Flow-6 Flow-1<--(GBR: 64 Kbps) | | Flow-4 | Flow-2 | | | | | Flow-1 | | | Flow-3 | | | |_|_| DSCP-X | | | ( )<--(Per-Session-AMBR: 1 Mbps) : | | | | | | DSCP-Z : | | | | | : : | | | | | | +=====+ +==:=v+ | | | | '- -- - - - --| | | : o|--' | | | '- - --- - - -| | __ | v o|----' | '- - - - - - - -| | _--' '--_ | o--|------' | | ( ) | | | MAG |=====( IP Network )=====| LMA | | | ( ) | | ,- - - - - - - - -| | '--__--' | o|-- - -, ,- - -- - -- - -| | | o|--- , | | | ,- - - - -- -| | | o|--, | | | | +=====+ +====^+ | | | |_|_| : | | | ( _ _ )<--(Per-Session-AMBR: 2 Mbps) : | | | | | | DSCP-Y | | | | | | | | | | | | | | | Flow-6 Flow-2 | | | | | | Flow-5 (MBR: 100 Kbps) Flow-3 | | | Flow-4 (GBR: 64 Kbps) Flow-5 | | | +=======+ | MN-2 | +=======+ Figure 1: QoS Support Figure 1 illustrates the support of QoS services in a Proxy Mobile IPv6 domain. The local mobility anchor and the mobile access gateway have negotiated QoS parameters for the mobility sessions belonging to MN-1 and MN-2. The negotiated QoS parameters include a Per-Session- AMBR of 1 Mbps and 2 Mbps for MN-1 and MN-2 respectively. Furthermore, different IP flows from MN-1 and MN-2 are given
different QoS service treatment, for example, a GBR of 64 Kbps for Flow-1 and Flow-4 is assured, a DSCP marking enforcement of "Z" on Flow-6, and an MBR of 100 Kbps on Flow-5.3.1. Quality-of-Service Option -- Usage Examples
Use Case 1: Figure 2 illustrates a scenario where a local mobility anchor initiates a QoS Service Request to a mobile access gateway. +-----+ +-----+ +-----+ | MN | | MAG | | LMA | +-----+ +-----+ +-----+ | | | 1) |---- MN Attach ----| | 2) | |------ PBU ------->| 3) | |<----- PBA --------| | | | 4) | |o=================o| | | PMIPv6 Tunnel | | | | | (LMA initiates QoS Service Request) | 5) | |<----- UPN (QoS)---| | | | | (MAG proposes a revised QoS Request) | 6) | |------ UPA (QoS')->| | | | 7) | |<----- UPN (QoS')--| 8) | |------ UPA (QoS')->| | QoS Rules ---| | 9) | Established <-| | QoS Rules ---| 10) | ---| Established <-| | | | ---| 11) |<----------------->| | Figure 2: LMA-Initiated QoS Service Request o (1) to (4): MAG detects the mobile node's attachment to the access link and initiates the signaling with the local mobility anchor. Upon completing the signaling, the LMA and MAG establish the mobility session and the forwarding state. o (5) to (8): The LMA initiates a QoS Service Request to the mobile access gateway. The trigger for this service can be based on a trigger from a policy function, and the specific details of that trigger are outside the scope of this document. The LMA sends an Update Notification (UPN) message [RFC7077] to the MAG. The message includes the QoS option (Section 4.1), which includes a set of QoS parameters. On determining that it cannot support the
requested QoS Service Request for that mobile, the MAG sends an
Update Notification Acknowledgement (UPA) message. The message
contains a revised QoS option with an updated set of QoS
attributes. The LMA accepts the revised QoS Service Request by
sending a new Update Notification message including the updated
QoS option.
o (9) to (11): Upon successfully negotiating a QoS Service Request,
the MAG and the LMA install the QoS rules for that Service
Request. Furthermore, the MAG (using access-technology-specific
mechanisms) installs the QoS rules on the access network.
Use Case 2: Figure 3 illustrates a scenario where a mobile access
gateway initiates a QoS Service Request to a local mobility anchor.
+-----+ +-----+ +-----+
| MN | | MAG | | LMA |
+-----+ +-----+ +-----+
| | |
1) |---- MN Attach ----| |
2) | |------ PBU ------->|
3) | |<----- PBA --------|
| | |
4) | |o=================o|
| | PMIPv6 Tunnel |
| | |
| (MAG initiates QoS Service Request) |
5) | |------ PBU (QoS)-->|
6) | |<----- PBA (QoS)---|
| QoS Rules ---| |
7) | Established <-| | QoS Rules ---|
8) | ---| Established <-| |
| | ---|
9) |<----------------->| |
Figure 3: MAG-Initiated QoS Service Request
o (1) to (4): MAG detects the mobile node's attachment to the access
link and initiates the signaling with the local mobility anchor.
Upon completing the signaling, the LMA and MAG establish the
mobility session and the forwarding state.
o (5) to (6): The MAG initiates a QoS Service Request to the local
mobility anchor. The trigger for this service can be based on a
trigger from the mobile node using access-technology-specific
mechanisms. The specific details of that trigger are outside the
scope of this document. The MAG sends a Proxy Binding Update
(PBU) message [RFC5213] to the LMA. The message includes the QoS
option (Section 4.1), which includes a set of QoS parameters. The
LMA agrees to the proposed QoS Service Request by sending a Proxy
Binding Acknowledgement (PBA) message.
o (7) to (9): Upon successfully negotiating a QoS Service Request,
the MAG and the LMA install the QoS rules for that Service
Request. Furthermore, the MAG using access-technology-specific
mechanisms installs the QoS rules on the access network.
3.2. Quality-of-Service Attributes -- Usage Examples
This section identifies the use cases where the Quality-of-Service
option (Section 4.1) and its attributes (Section 4.2) defined in this
document are relevant.
o The subscription policy offered to a mobile subscriber requires
the service provider to enforce Aggregate Maximum Bit Rate (AMBR)
limits on the subscriber's IP traffic. The local mobility anchor
and the mobile access gateway negotiate the uplink and the
downlink AMBR values for the mobility session and enforce them in
the access and the home network. The QoS option (Section 4.1)
with the QoS attributes Per-Session-Agg-Max-DL-Bit-Rate
(Section 4.2.3) and Per-Session-Agg-Max-UL-Bit-Rate
(Section 4.2.4) is used for this purpose.
o In Community Wi-Fi deployments, the residential gateway
participating in the Wi-Fi service is shared between the home user
and the community Wi-Fi users. In order to ensure the home user's
Wi-Fi service is not impacted because of the community Wi-Fi
service, the service provider enables Guaranteed Bit Rate (GBR)
for the home user's traffic. The QoS option (Section 4.1) with
the QoS attributes Guaranteed-DL-Bit-Rate (Section 4.2.8) and
Guaranteed-UL-Bit-Rate (Section 4.2.9) is used for this purpose.
o A mobile user using the service provider's Voice over IP
infrastructure establishes a VoIP call with some other user in the
network. The negotiated call parameters for the VoIP call require
a dedicated bandwidth of certain fixed value for the media flows
associated with that VoIP session. The application function in
the VoIP infrastructure notifies the local mobility anchor to
enforce the GBR limits on that IP flow identified by the flow
definition. The QoS option (Section 4.1) with the QoS attributes
Guaranteed-DL-Bit-Rate (Section 4.2.8), Guaranteed-UL-Bit-Rate
(Section 4.2.9), and QoS-Traffic-Selector (Section 4.2.10) is used
for this purpose.
o An emergency service may require network resources in conditions
when the network resources have been fully allocated to other
users and the network may be experiencing severe congestion. In
such cases, the service provider may want to revoke resources that
have been allocated and reassign them to emergency services. The
local mobility anchor and the mobile access gateway negotiate
Allocation and Retention Priority (AARP) values for the IP
sessions associated with the emergency applications. The QoS
option (Section 4.1) with the QoS attribute Allocation-Retention-
Priority (Section 4.2.5) is used for this purpose.
(page 12 continued on part 2)