ETSI TR 102 806 V1.1.1 (2009-11)

User Group; Analysis of current End-to-End QoS standardization state

DTR/USER-00031

General Information

• Status: Published
• Publication Date: 29-Nov-2009
• Technical Committee: USER - User Group
• Current Stage: 12 - Completion
• Due Date: 19-Nov-2009
• Completion Date: 30-Nov-2009

Standards Content (Sample)

Technical Report
User Group;
Analysis of current End-to-End QoS standardization state

2 ETSI TR 102 806 V1.1.1 (2009-11)

Reference
DTR/USER-00031
Keywords
QoS, Interface
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
Individual copies of the present document can be downloaded from:
http://www.etsi.org
The present document may be made available in more than one electronic version or in print. In any case of existing or
perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF).
In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive
within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, please send your comment to one of the following services:
http://portal.etsi.org/chaircor/ETSI_support.asp
Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2009.
All rights reserved.
TM TM TM TM
DECT , PLUGTESTS , UMTS , TIPHON , the TIPHON logo and the ETSI logo are Trade Marks of ETSI registered
for the benefit of its Members.
TM
3GPP is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners.
LTE™ is a Trade Mark of ETSI currently being registered
for the benefit of its Members and of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 ETSI TR 102 806 V1.1.1 (2009-11)
Contents
Intellectual Property Rights . 4
Foreword . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 9
4 NGN Context . . 11
4.1 User centric . 12
4.2 Mobility . 14
4.3 Heterogeneous environment . 18
4.3.1 IMS Architecture (3GPP) . 19
4.3.2 TISPAN NGN architecture . 22
4.4 Conclusion . 23
5 Requirement for QoS continuity . 24
6 Analysis of related work for QoS . 25
6.1 Control plane . 25
6.1.1 MIH . 26
6.1.2 MIPv6 . 30
6.1.3 NSIS. 31
6.1.4 SIP . 34
6.2 Management Plane . 36
6.2.1 Policy control . 36
6.2.2 Diameter . 40
6.3 User plane (CPN: Customer Premises Network). 42
6.3.1 Service provided in CPN . 42
6.3.2 CPN architecture model interacting with the NGN/IMS networks . 44
7 Conclusion and next steps . 46
Annex A: Bibliography . 47
History . 48

ETSI
4 ETSI TR 102 806 V1.1.1 (2009-11)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI User Group (USER).
Introduction
This analysis of the current End-to-End (E2E) QoS standardization state was carried out as a preliminary work to the
drafting of the multipart deliverable TR 102 805 "User Group; End-to-end QoS management at the Network Interfaces".
Its publication was decided, considering that it could be useful to other ETSI TB.
ETSI
5 ETSI TR 102 806 V1.1.1 (2009-11)
1 Scope
The present document provides information on the standards and documents available in the area of end to end QoS.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
Not applicable.
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] 3GPP TR 25.832 (V4.0.0): "3rd Generation Partnership Project; Technical Specification Group
Radio Access Network; Manifestations of Handover and SRNS Relocation (Release 4)".
[i.2] ETSI TS 124 229 (V5.23.0): "Digital cellular telecommunications system (Phase 2+); Universal
Mobile Telecommunications System (UMTS); LTE; Internet Protocol (IP) multimedia call control
protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP);
Stage 3 (3GPP TS 24.229 version 5.23.0 Release 5)".
[i.3] ETSI EG 202 132 (V1.0.0): "Human Factors (HF); User Interfaces; Guidelines for generic user
interface elements for mobile terminals and services".
[i.4] ETSI ES 282 001: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Functional Architecture".
[i.5] ETSI ES 282 003 (V2.0.0): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Resource and Admission Control Sub-System (RACS):
Functional Architecture".
ETSI
6 ETSI TR 102 806 V1.1.1 (2009-11)
[i.6] ETSI ES 282 004 (V2.0.0): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); NGN Functional Architecture; Network Attachment
Sub-System (NASS)".
[i.7] ETSI ES 282 007 (V2.1.1): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); IP Multimedia Subsystem (IMS); Functional architecture".
[i.8] ETSI ES 283 003 (V1.1.1): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); IP Multimedia Call Control Protocol based on Session
Initiation Protocol (SIP) and Session Description Protocol (SDP) Stage 3 [3GPP TS 24.229
(Release 7), modified]".
[i.9] ETSI TR 102 805-1 (V1.1.1): "User Group; End-to-end QoS management at the Network
Interfaces; Part 1: User's E2E QoS - Analysis of the NGN interfaces (user case)".
[i.10] ETSI TR 102 805-2 (V1.1.1): "User Group; End-to-end QoS management at the Network
Interfaces; Part 2: Control and management planes solution - QoS continuity".
[i.11] ETSI TS 123 207 (V7.0.0): "Digital cellular telecommunications system (Phase 2+); Universal
Mobile Telecommunications System (UMTS); End-to-end Quality of Service (QoS) concept and
architecture (3GPP TS 23.207 version 7.0.0 Release 7)".
[i.12] ETSI TS 123 228 (V8.6.0): "Digital cellular telecommunications system (Phase 2+); Universal
Mobile Telecommunications System (UMTS); IP Multimedia Subsystem (IMS); Stage 2
(3GPP TS 23.228 version 8.6.0 Release 8)".
[i.13] ETSI TS 129 208 (V6.7.0): "Digital cellular telecommunications system (Phase 2+); Universal
Mobile Telecommunications System (UMTS); End-to-end Quality of Service (QoS) signalling
flows (3GPP TS 29.208 version 6.7.0 Release 6)".
[i.14] ETSI TS 129 212 (V8.1.0): "Universal Mobile Telecommunications System (UMTS);Policy and
charging control over Gx reference point (3GPP TS 29.212 version 8.1.0 Release 8)".
[i.15] ETSI TS 129 214 (V8.2.0): "Universal Mobile Telecommunications System (UMTS);Policy and
charging control over Rx reference point (3GPP TS 29.214 version 8.2.0 Release 8)".
[i.16] ETSI TS 182 012 (V2.1.4): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); IMS-based PSTN/ISDN Emulation Sub-system (PES);
Functional architecture".
[i.17] ETSI TS 182 027 (V2.0.0): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); IPTV Architecture; IPTV functions supported by the
IMS subsystem".
[i.18] ETSI TS 182 028 (V2.0.0): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); IPTV Architecture; Dedicated subsystem for IPTV
functions".
[i.19] ETSI TS 185 005 (V2.0.0): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Services requirements and capabilities for customer
networks connected to TISPAN NGN".
[i.20] ETSI TS 185 006 (V2.0.0): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Customer Devices architecture and interfaces and Reference
Points".
[i.21] IEEE 802.11b: "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)
specifications: Higher-Speed Physical Layer Extension in the 2.4 GHz Band".
[i.22] IEEE 802.21: "Media Independent Handover; QOS Framework and parameters",
February 17, 2006.
[i.23] ITU-T Recommendation Q.1706/Y.2801 (2006): "Mobility management requirements for NGN".
[i.24] IETF RFC 3261 (2002): "SIP(Session Initiation Protocol)".
ETSI
7 ETSI TR 102 806 V1.1.1 (2009-11)
[i.25] IETF RFC 3344 (2002): "Mobility Support in IPv4".
[i.26] IETF RFC 3753: "Mobility Related Terminology", June 2004. J. Manner, M. Kojo et al.
[i.27] IETF RFC 3775 (2004): "Mobility Support in IPv6".
[i.28] IETF RFC 4006 (2005): "Diameter Credit-Control Application".
[i.29] IETF RFC 4080: "NSIS Framework" June 2005.
[i.30] NLSP for QoS.
NOTE: Available at: http://www.ietf.org/html.charters/nsis-charter.html.
[i.31] QoS NSLP QSPEC Template.
NOTE: Available at: http://www.ietf.org/html.charters/nsis-charter.html
[i.32] TeleManagement Forum.
NOTE: Available at: http://www.tmforum.org.
[i.33] Gilles Bertrand: "The IP Multimedia Subsystem(IMS)-An overview".
[i.34] Th. Magedanz Senior Member IEEE, F.C. de Gouveia, "IMS-the IP Multimedia System as NGN
Service Delivery Platform", Bektrotechnik & Informationstechnik (2006), pp. 271-276.
[i.35] IETF RFC 2475: "An Architecture for Differentiated Service".
[i.36] IETF RFC 2474: "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6
Headers ".
[i.37] IETF RFC 1633: "Integrated Services in the Internet Architecture: an Overview".
[i.38] IEEE 802.11g: "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: Further Higher Data Rate Extension in the 2.4 GHz Band".
[i.39] ETSI TS 129 207: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Policy control over Go interface (3GPP TS 29.207
Release 6)".
[i.40] ITU: "Study Group 19 - Contribution 25: Considerations of horizontal handover and vertical
handover, 2007".
[i.41] ETSI TS 129 214 (V7.1.0): "Universal Mobile Telecommunications System (UMTS); Policy and
charging control over Rx reference point (3GPP TS 29.214 Release 7)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
AmbientGrid: information inference (AmbientGrid) based on the profiles' matching, to structure with grid covering the
needed user centric environment
Class of Service (CoS): way of traffic management in the network by grouping similar types of traffic and treating
them as its own level of service priority
ETSI
8 ETSI TR 102 806 V1.1.1 (2009-11)
DiffServ networks: classify packets into one of a small number of aggregated flows or 'classes', based on the DiffServ
codepoint (DSCP) in the packet's IP header
NOTE: This is known as behaviour aggregate (BA) classification (RFC 2475 [i.35]). At each DiffServ router,
packets are subjected to a 'per-hop behaviour' (PHB), which is invoked by the DSCP (RFC 2474 [i.36])
horizontal handove: handover within homogeneous access networks
NOTE 1: Generally it is referred to as the Intra-AN handover.
NOTE 2: ITU: Study Group 19 - Contribution 25: Considerations of horizontal handover and vertical
handover, 2007 [i.40]
infosphere: decisional knowledge base managing, in the real time, all the personalization and ambient environment
information
IntServ (integrated services architecture): set of extensions to the traditional best effort model of the Internet with the
goal of allowing end-to-end QoS to be provided to applications
NOTE 1: One of the key components of the architecture is a set of service; the current set of services consists of the
controlled load and guaranteed services. The architecture assumes that some explicit setup mechanism is
used to convey information to routers so that they can provide requested services to flows that require
them. While RSVP is the most widely known example of such a setup mechanism, the IntServ
architecture is designed to accommodate other mechanisms.
NOTE 2: See RFC 1633 [i.37].
multi-homing: user's services can be provided by more than one service or network provider
network mobility: network's ability, where a set of fixed or mobile nodes are networked to each other, to change, as a
unit, its point of attachment to the corresponding network upon the network's movement itself
policy control: adaptation and configuration of QoS according to particular goals dependent of user, network operator
and service provider
QoS Classification: definition of class priority for QoS by describing traffic condition or performance parameters
QoS handover: ensures QoS state establishes when vertical/horizontal handover occurs
QoS Interworking: ensures the transfer of all different types of packet data with different QoS parameters in
heterogeneous environment whenever the ANs and CNs are of different releases and types by mapping the QoS
attributes
service mobility: ability to consistently provide services to the end-user, to maintain the expected QoS, at the system's
initiative, regardless of the end-user's location, terminals, or networks.
NOTE: To maintain the service continuity, the session mobility is used.
terminal mobility: user uses his terminal to move across the same or different networks while having access to the
same set of subscribed services
user mobility: ability for a subscriber to move to different physical locations and be able to use one or more devices
connected to one or more access networks to gain access to their services without interruption
user session: period of communication between one user and another or other users or servers characterized by a
starting time and a termination time, including setting up the relation of the user equipment, access network, core
network and services
userware: innovative user centric middleware (Userware) enhancing the seamless feasibility along with the location
and activity, personalization and user's ambient contexts
vertical handover: handover across heterogeneous access networks. Generally, it is referred to as the Inter-AN
handover
NOTE: ITU STUDY GROUP 19 - CONTRIBUTION 25: Considerations of horizontal handover and vertical
handover, 2007 [i.40].
ETSI
9 ETSI TR 102 806 V1.1.1 (2009-11)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3GPP The 3rd Generation Partnership Project
AAA Authentication, Authorization and Accounting
ACF Admission Control Function
ACK ACKnowledgement
AMF Access Management Function
AN Access Network
API Application Programming Interface
A-RACF Access Resource and Admission Control Function
ARF Access Relay Function
AS Application Server
ASF Application Server Functions
ASP Application Service Provider
AVP Attribute-Value-Pair
BA Binding Acknowledgement
BGCF Breakout Gateway Control Function
BGF Border Gateway Function
BU Binding Update
CAC Connection Admission Control
C-BGF Core Border Gateway Function
CCA Credit-Control Answer
CCR Credit-Control Request
CDR Charging Data Records
CN Core Network
CND Customer Network Devices
CNG Customer Network Gateway
CNGCF Customer Network Gateway Configuration Function
CoA Care of Address
COPS Common Open Policy Service
CoS Class of Service
CPE Customer Premises Equipment
CPN Customer Premises Network
CSCF Call Session Control Function
CTF Charging Trigger Function
DCCP Datagram Congestion Control Protocol
DiffServ Differentiated Services
DSCP DiffServ CodePoint
E2E QoS End-to-End QoS
ETSI European Telecommunications Standards Institute
FBC Flow Based Charging
GIST Generic Internet Signalling Transport
GPRS General Packet Radio Service
GSM Global System for Mobile Communications
HA Home Agent
HHO Horizontal HandOver
HLR Home Location Register
HoA Home Address
HSS Home Subscriber Server
I/S CSCF Interrogating/Serving CSCF
I-BGF Interconnection Border Gateway Function
IEEE Institute of Electrical & Electronic Engineers
IETF Internet Engineering Task Force
IM IP Multimedia
IMS IP based Multimedia Subsystem
IN Intelligent Network
IntServ Integrated Services
IP-CAN IP-Connectivity Access Networks
IPTV Internet Protocol TeleVision
ETSI
10 ETSI TR 102 806 V1.1.1 (2009-11)
ISC IP multimedia Service Control
ISP Internet Service Provider
ITU-T International Telecommunication Union - Telecommunication standardization sector
IWU InterWorking Unit
L2TF Layer 2 Terminal Function
M2M Machine-to-Machine
MAC Medium Access Control
MGCF Media Gateway Control Function
MICS Media Independent Command Service
MIES Media Independent Event Service
MIH Media Independent Handover
MIHF Media Independent Handover Function
MIIS Media Independent Information Service
MIPv4 Mobile IP v4
MIPv6 Mobile IP v6
MN Mobile Node
MRFC Media Resource Function Controller
MRFP Media Resource Function Processor
NACF Network Access Configuration Function
NASS Network Attachment SubSystem
NAT Network Address Translation
NGN Next Generation Network
NGS Next Generation Service
NSIS Next Steps In Signalling
NSLP NSIS Signalling Layer Protocols
NTLP NSIS Transport Layer Protocol
OCS Online Charging System
OSA Open Service Access
OSI Open System Interconnection
PCC Policy and Charging Control
PCEF Policy Enforcement Point
PCRF Policy and Charging Rule Function
P-CSCF Proxy CSCF
PDA Personal Digital Assistant
PDBF Profile Data Base Function
PDG Packet Data Gateway
PDP Policy Decision Point
PDU Protocol Data Unit
PEF Policy Enforcement Function
PEP Policy Enforcement Point
PES PSTN/ISDN Emulation Subsystem
PHB Per Hop Behaviour
PHY PHYsical layer
PLMN Public Land Mobile Network
PS Proxy Server
PSTN Public Switched Telephone Network
QNF QoS NLSP Forwarder
QNI QoS NLSP Initiator
QNR QoS NLSP Responder
QoS Quality of Service
QoSM Quality of Service Managemer
QSPEC QoS SPECification
RACS Resource and Admission Control Subsystem
RCEF Resource Control Enforcement Function
RMF Resource Management Function
RS Register Server
RSVP Resource Reservation Protocol
RTP Real Time Protocol
SBLP Service Based Local Policy
SCIM Service Capability Interaction Manager
SCP Service Control Point
SCS Service Capability Server
ETSI
11 ETSI TR 102 806 V1.1.1 (2009-11)
SCTP Stream Control Transmission Protocol
SDP Session Description Protocol
SID Session IDentifier
SIP Session Initiation Protocol
SLA Service Level Agreement
SLF Subscription Locator Function
SLS Service Level Specification
SP Service Provider
SPDF Service Policy Decision Function
SSF Service Switch Function
TCP Transmission Control Protocol
TE Terminal Equipment
T-MGF Trunk Media Gateway Function
TPF Traffic Plane Function
UAAF User Access Authorization Function
UDP User Datagram Protocol
UE User Equipment
UMA Unlicensed Mobile Access
UMTS Universal Mobile Telecommunications Systems
UMTSc Universal Mobile Telecommunications Systems
URL Universal Resource Locator
VHE Virtual Home Environment
VHO Vertical HandOver
VoIP Voice over IP
WAG Wireless Access Gateway
WLAN Wireless Local Area Network
4 NGN Context
The successor of the 3G network is a single All-IP infrastructure which is referred to as NGN (Next Generation
Network). A major characteristic of the Next Generation Network is its ability to handle heterogeneous and mobile
environments for users and service providers.
One can consider four different types of mobility: User mobility, Terminal mobility, Network mobility and Service
mobility. Moreover, heterogeneity exists in user's terminals, access networks, core networks as well as in services.
The ability to provide seamless mobility and adaptive quality of service in such a heterogeneous environment is THE
key to the success of Next-Generation Networks.
Our analysis of the context led us to highlight innovative properties (clause 4.1).
Users wish to have a continuous multimedia service in a single session whether they are moving around (terminal
mobility) or changing terminal (user mobility). This service session is user-centric, meaning that a user should have a
continuity of service based on customization. Next service generation should have the self-management ability to
dynamically accommodate user requests by adding or changing service components in a single service session.
ETSI
12 ETSI TR 102 806 V1.1.1 (2009-11)

Figure 1: NGN context
In this clause, a basic introduction on the three main characteristics of NGN is provided: the User Centric conception
(clause 4.1), the heterogeneous environment (clause 4.2), and the general mobility in NGN (clause 4.3). A conclusion is
then proposed in clause 4.4.
4.1 User centric
Telecommunication evolved from system centric (user has to comply with various treatments) to network centric (user
has to comply with various connections), and now to User centric. User information, QoS requirements and preferences
are defined in the user's profile (Figure 2). In this new context, a common understanding about services, priorities,
responsibilities, etc, is needed between the service provider and the user. This is expected to lead, in the case of
business users, to a formal Service Level Agreement (SLA) or, in the case of the general public, to QoS commitments
of the provider included in the service contract according to the relevant regulation.

Figure 2: User centric
ETSI
13 ETSI TR 102 806 V1.1.1 (2009-11)
User centric means that users can access services, in a customized way with a single authentication and "always in a
unique user session". This concept contains four essential requirements explained below:
• Adaptable accessibility to services regardless the terminal used
End users may have several User Equipments (UE) in a Seamless Userware vision, for instance a computer, a
PDA, a mobile telephone etc, all trying to access the same service. Each of these equipments has its specific
context and conditions of use, and each user has his specific preferences.
In such a situation, one key question is how to adapt services to a chosen terminal while complying to user's
preferences.
• Unique user session for multimedia services (Continuity of service)
During an on-going session, a user can enjoy different services from different providers. For example, during a
telephone call, a user can add a Videophone service, and a movie program which may later on be transferred to
a PDA. Users expect such service continuity to be provided via a unique user session.
• Customization of service
The NGS (Next Generation Service) concept considers services as a flexible composition of autonomous
service components customizable according to user's preferences and to the user profile. Thus, user's
preferences should be taken into consideration while managing service composition across heterogeneous
networks.
• Better selection of connectivity with QoS
Today's technology allows a terminal to be able to access services through different access networks (WiFi,
GSM, UMTS, etc.). This means that a user can switch from one access mode to another one in a dynamic
manner according to user's preferences (QoS, location, availability, etc.).
All these four characteristics are subtended by the SLA concept.
SLA (Service Level Agreement) is an abbreviation often used in the context of contract between business users and
their providers. In the present document, the meaning of SLA has been mapped to cover as well the case of the QoS
commitments implied in the provision of telecommunication services to the general public.
The TeleManagement Forum [i.32] defines a SLA as "a formal negotiated agreement between two parties, sometimes
called a service level guarantee. It is a contract (or part of one) that exists between the service provider and its customer,
to create a common understanding about services, priorities, responsibilities, etc."
In fact, the SLA is considered from a service development point of view, as shown in its Life Cycle (Figure 3).

Figure 3: SLA Life Cycle
1) SLA Development: In this phase the SLA templates are developed.
2) Negotiation and Sales: The SLA is negotiated and the contracts are notified.
3) Implementation: The SLA is generated (activated).
ETSI
14 ETSI TR 102 806 V1.1.1 (2009-11)
4) Execution: The SLA is executed, monitored and maintained.
5) Assessment (of the SLA performance): A re-evaluation of the initial SLA template might be done.
SLA implementation helps service providers (including third-party service providers) and service users to clarify some
of the services responsibilities regarding the expected quality. QoS (Quality of Services) indicators should avoid any
ambiguity in understanding the quality of the service.
In addition, in the process of SLA, there is a commitment to quantify the quality of service (QoS indicators), and
meanwhile, to perform regular statistics, analysis, reporting and management. These initiatives can guide the customer
in exploring the potential settings, to achieve maximum "user benefit".
SLA is relevant to the management plane and to the informational dimension. This contract between the provider and
the user is static. When dealing with the more complex context of NGN which encompasses mobility and heterogeneity,
the trend will be to get a dynamic contract.
4.2 Mobility
Mobility gives users ability to connect from anywhere, anytime to any service with any type of terminal. In the NGN
context, mobility allows users to communicate regardless of location, device, access mode and network across multiple
spatial domains. The existing solutions for mobility include horizontal handover (HHO) and vertical handover (VHO).
The horizontal handover is provided via mode L3 through the technology "Mobile IP". Media Independent
Handover (MIH) is intended to manage seamless connectivity with different wireless networks in MAC and PHY
layers.
Four kinds of mobility exist in such a NGN context:
• User Mobility refers to the ability for the user to move to different physical locations and be able to use one or
more devices connected to one or more access networks to gain access to their services without
interruption [i.3].
Figure 4: User Mobility
• Network mobility refers to the ability of networks, where a set of fixed or mobile nodes are networked to each
other, to change, as a unit, its point of attachment to the corresponding network upon the network's movement
itself (this kind of mobility is out of our scope of research).
EXAMPLE: Ad-hoc network, military network.
• Service Mobility refers to the ability of services to be accessible and deliverable independently of network,
terminal or geographical location attributes [i.3] It includes the ability of the service level to consistently
provide customized services to the user, with the expected QoS, regardless of the user's location. This allows
users to maintain access to their services even while moving or changing devices or network service providers.
ETSI
15 ETSI TR 102 806 V1.1.1 (2009-11)

Figure 5: Service mobility
• Terminal Mobility refers to the ability of a terminal, while in motion, to access telecommunication services
from same or different networks and the capability of the commercial networks to identify and locate that
terminal [i.3].
NOTE: Source from ITU-T Recommendation Q.1706/Y.2801 [i.23].

Figure 6a: Mobility classifications according to network service quality

Figure 6b: Terminal Mobility
The key issue to achieve seamless mobility is for Service Providers to comply with the QoS contract.
ETSI
16 ETSI TR 102 806 V1.1.1 (2009-11)
Terminal mobility needs horizontal handover (HHO) in an homogenous network and vertical handover (VHO) in
heterogeneous access networks. Generally, HHO is referred to as the Intra-AN handover while VHO is referred to as
the Inter-AN handover [i.23]. Figure 7 illustrates both cases (HHO and VHO).

Figure 7: Horizontal handover and Vertical handover
Horizontal Handover (HHO) refers to a terminal whose location changes i.e. that moves across various access points
in one network or moves across different network access points, while maintaining access to one set of services. Such
mobility should allow the relocation of the terminal without any break. The change in the point of attachment may
sometimes temporarily disconnect the mobile terminal and disrupt communications in progress while the objective is to
ensure seamless communications.
The procedure for horizontal handover is handled mostly in layer 2. A layer 2 handover occurs when a mobile host's
connection changes from one access point to another. The procedure of this type of handover involves releasing the
connection from the former access point, establishing a connection to the new access point (though not necessarily in
this order), and updating the binding between a mobile host's IP address and its temporary layer 2 identifier (e.g. a
MAC address) on the sub-network at the access router. Two types of procedures are proposed [i.26]:
• Break-before-make handover: the former connection is released before the new connection is established;
data reception is interrupted for a short period of time. The service disruption can be avoided.
• Make-before-break handover: if the mobile host is capable of establishing connections to multiple access
points simultaneously, it can connect to the new access point before breaking its connection from the former
access point.
Broadly speaking, the handover will be conducted by analyzing the signal received from the two related cells, frame by
frame, involved and the best frame will be accepted. Several handover definitions have been proposed. For instance, in
UMTS (Universal Mobile Telecommunications System) [i.1], three different handovers have been defined: hard
handover, soft handover and softer handover.
a) Hard handover
It means that all the old radio links in the UE are removed before the new radio links are established. Hard
handover can be seamless or non-seamless. Seamless hard handover means that the handover is not perceptible
to the user. In practice a handover that requires a change of carrier frequency (inter-frequency handover) is
always performed as hard handover.
b) Soft Handover
It means that the radio links are added and removed in a way that the UE always keeps at least one radio link to
the UTRAN. Soft handover is performed by means of macro diversity, which refers to the condition that
several radio links are active at the same time. Normally soft handover can be used when the mobile is going to
another cell on the same frequency.
ETSI
17 ETSI TR 102 806 V1.1.1 (2009-11)
c) Softer Handover
Softer handover is a special case of soft handover where the radio links that are added and removed belong to
the same Node B. In softer handover, macro diversity with maximum ratio combining can be performed in the
Node B, whereas generally in soft handover on the downlink, macro diversity with selected combination is
applied.
Vertical Handover (VHO) is the solution for mobility in a heterogeneous network. It refers to a terminal which
location changes i.e. that moves among access points of a technology to another access point in a different technology
while maintaining access to the set of services. Such mobility should be seamless.
Cellular and WLAN technologies are shortly discussed as basic technologies for vertical handover, especially, VHO
between cellular technologies such as GPRS and WLAN such as IEEE 802.11b [i.21]/IEEE 802.11g [i.38].
Furthermore, the analysis can be extended to any combination of heterogeneous networks, including multiple
overlapping (more than 2) radio technologies. 3GPP provides solution for VHO between Wimax and GPRS.
Often VHO between heterogeneous networks such as WLAN/GPRS is managed at IP level and Mobile IP is
used see [i.25] and [i.27].
The interconnection between WLAN and GPRS in 3GPP architecture is represented below:

Figure 8: Interconnection between WLAN and GPRS in 3GPP architecture
Authentication, Authorisation and Accounting is managed by the HLR/HSS and Charging by the CS Online and
Offline.
The WAG - Wireless Access Gateway provides interconnection between access and 3GPP network. The WAG
manages IP tunnels, QoS mechanisms and it is responsible of roaming.
The PDG - Packet Data Gateway is the access point thru 3GPP network. It manages the tunnel for exchanges to the
WAG. The PDG is responsible of packet routing between Internet and the User. It can implement certain functions such
as NAT and QoS mechanisms.
The WLAN 3GPP IP proposes connection to Internet through the PLMN, and provides PLMN's services through
WLAN access such as SMS, MMS, IMS Services, etc.
ETSI
18 ETSI TR 102 806 V1.1.1 (2009-11)

Figure 9: Data traffic and signalling between WLAN and GPRS in 3GPP architecture
4.3 Heterogeneous environment
With the continuous evolution of services and technologies, the world of telecommunication becomes more and more
heterogeneous. Modern telecommunication networks consist of mobile network (such as GSM/GPRS/UMTS), fixed
network (such as Public Switched Telephone Network/ISDN), satellite network and wireless access networks (such as
wireless LAN (WiFi, WiMax) and Bluetooth networks), etc. The user devices are also becoming more diversified:
PDAs, laptops, cell phones, etc. which are now commonly used by the general public.
The growing number of a variety of services and multimedia applications in converging fixed and mobile IP networks
(called Next Generation Networks (NGN)) led to the definition of a Service Delivery Platform architecture known as an
IMS (IP Multimedia Subsystem) (with associated protocols: SIP, Diameter and Policy control protocols). IMS was
originally specified by 3GPP as part of the vision for evolving mobile networks beyond GSM and was extended later
for supporting other networks such as fixed line, WLAN, etc. by a number of standardization organizations, such as the
ITU-T and ETSI TISPAN; meanwhile the number of service providers and operators is growing in the NGN (Figure 10)
heterogeneous environment.
Figure 10: NGN heterogeneous environment
ETSI
19 ETSI TR 102 806 V1.1.1 (2009-11)
These heterogeneities have increased the complexity of the overall infrastructure. Problems of interoperability between
the various systems and handover/roaming between different accesses and providers should be solved according to the
QoS commitments.
The QoS problem in an heterogeneous environment is how to interoperate the QoS state. The policy could be used to
adapt QoS according to particular goals in heterogeneous networks. Such policy could be used for:
• optimal access network selection in case of handover, routing and connection redirection;
• resource and service adaptation in heterogeneous network environment;
• management of the interactions between heterogeneous networks for QoS provisioning.
IP Multimedia Subsystem (IMS) has emerged as an overlay service provisioning platform that operates in an
heterogeneous network environment. The IMS is defined by the 3rd Generation Partnership Projects (3GPP and 3GPP2)
and is an overlay service architecture that enables the efficient provision of an open set of highly integrated multimedia
services, combining web browsing, e-mail, instant messaging, VoIP, video conferencing, telephony, multimedia content
delivery, etc.
4.3.1 IMS Architecture (3GPP)
The IP Multimedia Core Network (IM CN) subsystem enables PLMN operators to offer their subscribers multimedia
services based on and built upon Internet applications, services and protocols. The IMS should enable the convergence
of voice, video, messaging, data and web-based technologies for the wireless user, and combine the growth of the
Internet with the growth in telecommunications. The complete solution for the support of IP multimedia applications
consists of terminals, IP-Connectivity Access Networks (IP-CAN), and the specific functional elements of the
IMS [i.12]. The IMS reference architecture including interfaces towards legacy networks and other IP based multimedia
systems is represented in Figure 11. Details of the roles of these entities are described in the 3GPP IMS architecture is
split into three layers: Service Layer, Control Layer and Connectivity Layer.

Figure 11: IMS architecture
ETSI
20 ETSI TR 102 806 V1.1.1 (2009-11)
The service layer consists of application and content servers to execute value-added services for the user. Three types of
Application Server Functions (ASF) can be accessed by the IMS through the ISC or Ma reference point (Figure 11).
• SIP Application Servers (SIP AS); A SIP Application Server may contain "Service Capability Interaction
Manager" (SCIM) functionality and other application s
...