ETSI TS 102 855 V1.1.1 (2011-03)

Technical Specification
Satellite Earth Stations and Systems (SES);
Broadband Satellite Multimedia (BSM);
Interworking and Integration of BSM
in Next Generation Networks (NGNs)

2 ETSI TS 102 855 V1.1.1 (2011-03)

Reference
DTS/SES-00305
Keywords
broadband, IMS, interworking, IP, satellite
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ETSI
3 ETSI TS 102 855 V1.1.1 (2011-03)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 8
4 NGN Impacts on BSM Networks . 10
4.1 Background . 10
4.2 NGN Network Architecture . 11
4.2.1 Service Stratum . 12
4.2.2 Transport Stratum . 12
4.2.2.1 Transport Control Sublayer . 12
4.2.2.2 Transport Processing Functions . 13
4.3 Service requirements . 13
4.3.1 General NGN Service Requirements . 13
4.3.2 BSM-Specific Service Requirements. 14
4.3.2.1 VOIP and convergence . 14
4.3.2.2 IPTV and IP video . 15
4.3.2.3 Live/linear TV . 15
4.3.2.4 Video on Demand (VoD) . 15
4.3.2.5 Emergency/Disaster Services . 15
4.3.2.6 Primary Infrastructure . 15
4.3.2.7 Infrastructure Support . 16
4.3.2.8 Smart Grid/telemetry . 16
4.4 Interworking requirements . 16
5 BSM/NGN Architecture . 16
5.1 BSM-Specific NGN Architecture . 16
5.2 Scenarios . 17
5.2.1 IMS Service Access - Star network-based (1) . 18
5.2.1.1 Message Flow Diagrams . 19
5.2.2 IMS Service Access - Mesh network based (2) . 21
5.2.2.1 Message Flow Diagrams . 21
5.2.3 Efficient IMS Peering (3) . 23
5.3 Detailed Functional Architecture. 23
5.3.1 BSM RACS . 23
5.3.1.1 SPDF . 24
5.3.1.2 A-RACF . 24
5.3.2 BSM NASS . 25
5.3.2.1 Network Access Configuration Function (NACF) . 26
5.3.2.2 Connectivity session Location and repository Function (CLF) . 26
5.3.2.3 User Authentication and Authorization Function (UAAF) . 26
5.3.2.4 Profile Data Base Function (PDBF) . 26
5.3.2.5 CNG Configuration Function (CNGCF) . 27
5.4 Interfaces and Reference Points . 27
6 BSM Adaptation Functions for NGN . 27
6.1 Signalling Application Server . 28
6.2 BSM IWF . 29
6.3 Mobile/Fixed Satellite System Convergence. 29
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4 ETSI TS 102 855 V1.1.1 (2011-03)
Annex A (informative): The IP Multimedia Subsystem (IMS) . 30
A.1 Overview . . 30
A.2 IMS Logical Elements . 31
A.2.1 The Call Session Control Functions (CSCF) . 31
A.2.2 Media Gateway Control Function (MGCF) . 32
A.2.3 Multimedia Resource Function Controller (MRFC) . 32
A.2.4 Breakout Gateway Control Function (BGCF) . 32
A.2.5 Interconnection Border Control Function (IBCF) . 32
Annex B (informative): BSM/IMS Procedures . 33
B.1 ST Attachment and Initialization . 33
B.1.1 SIP Usage . 33
B.1.2 ST Attachment and Initialization Overview . 33
B.2 ST Registration . 35
B.3 The SIP-Based Service Discovery Mechanism . 35
Annex C (informative): Further Examples of BSM/NGN Scenarios . 36
C.1 BSM Access-only scenario . 36
C.2 Satellite-based IMS . 36
C.3 Enhanced Satellite-based IMS . 37
Annex D (informative): Bibliography . 38
History . 39

ETSI
5 ETSI TS 102 855 V1.1.1 (2011-03)
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 Specification (TS) has been produced by ETSI Technical Committee Satellite Earth Stations and
Systems (SES).
Introduction
The Next Generation Network (NGN) is seen as the future universal network based on IP into which different network
technologies will be integrated. The BSM network [1] is an example of one of these technologies. Working groups at
ETSI (TISPAN), ITU and others (3GPP, TMF etc) have defined many of the functional characteristics of the NGN [4],
[8], [9] and their work is continuing.
The BSM network has been defined with many of the same features (IP protocol based packetised transport, modular
and interoperable control plane elements, a largely access agnostic architecture, etc.) necessary for compatibility with
the NGN. Hence the BSM network is a candidate for NGN integration.
The BSM system has also been defined as a functional architecture to implement IP-based services in a standardised
way over a variety of satellite technologies, and with the potential to operate these services when the BSM network is
integrated into heterogeneous networks [i.1], [i.2]. The BSM architecture is characterised by the SI-SAP which defines
the separation between common Satellite-Independent (SI) protocol layers and alternative lower Satellite-Dependent
(SD) layers [2]. In addition, interfaces with higher-layer protocols and peer external networks and customer equipment
are provided where appropriate. This is also very compatible with the NGN architecture which wants to clearly
distinguish between transport specific and service specific functions.
One of the main functional building blocks of the NGN is the IP Multimedia Subsystem (IMS) [6]. The IMS provides a
means initially for fixed-mobile and now many network convergence and interworking functionality for IP-based
services. These include today IPTV, fixed and mobile voice and presence, and potential new services like video
conferencing, peer-peer gaming etc. in the future. The definition of the NGN and the specifications of the IMS core
functionality are still evolving in the standards bodies, but are sufficiently mature and stable to be able to define the
potential interactions with the BSM network. Basic BSM network services could be deployed over the current IMS, but
as IMS-based networks and applications mature, converged BSM services can be offered in conjunction with other
satellite and terrestrial wireline and wireless networks using a common subscriber management system and control
plane.
The present document will specify how BSM networks can be integrated into the NGN architecture.
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6 ETSI TS 102 855 V1.1.1 (2011-03)
1 Scope
The integration and interoperability of BSM networks with the NGN is specified in terms of the functional architecture
and associated functions and interfaces.
The present document is based on and uses TISPAN (release 2) definitions and terminology (since TISPAN release 3 is
not yet fully specified).
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
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 necessary for the application of the present document.
[1] ETSI TS 102 292: "Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia
(BSM) services and architectures; Functional architecture for IP interworking with BSM
networks".
[2] ETSI TS 102 357: "Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia
(BSM); Common Air interface specification; Satellite Independent Service Access Point SI-SAP".
[3] ETSI TS 102 462: "Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia
(BSM); QoS Functional Architecture".
[4] ETSI TS 102 672: "Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia
(BSM); Management Functional Architecture".
[5] ETSI ES 282 001: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN);NGN Functional Architecture".
[6] ETSI ES 282 007: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); IP Multimedia Subsystem (IMS); Functional architecture".
[7] ITU-T Recommendation Y.1291: "An architectural framework for support of Quality of Service in
packet networks".
[8] ITU-T Recommendation Y.2011: "General principles and general reference model for NGN".
[9] ITU-T Recommendation Y.2012: "Functional requirements and architecture of NGN release 1".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 101 984: "Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia
(BSM); Services and architectures".
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7 ETSI TS 102 855 V1.1.1 (2011-03)
[i.2] ETSI TR 101 985: "Satellite Earth Stations and Systems (SES); Broadband Satellite Multimedia;
IP over Satellite".
[i.3] ETSI TR 180 000: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Terminology".
[i.4] ETSI TS 123 002: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Network architecture (3GPP TS 23.002)".
[i.5] IETF RFC 3261: "Session Initiation Protocol".
[i.6] IETF RFC 3320: "Signalling Compression (SIGCOMP)".
[i.7] IETF RFC 5049: "Applying Signaling Compression (SigComp) to the Session Initiation Protocol
(SIP)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
architecture: abstract representation of a communications system
NOTE: Three complementary types of architecture are defined:
- Functional Architecture: the discrete functional elements of the system and the associated logical
interfaces.
- Network Architecture: the discrete physical (network) elements of the system and the associated
physical interfaces.
- Protocol Architecture: the protocol stacks involved in the operation of the system and the
associated peering relationships.
BSM Network: BSM subnetwork together with the BSM interworking and adaptation functions that are required to
provide IP interfaces (i.e. layer 3 and below) to attached networks
BSM Subnetwork: all the BSM network elements below the Satellite Independent Service Access Point (SI-SAP)
BSM System (BSMS): BSM System comprises a BSM Network together with the NMC and NCC plus any additional
elements that are required to provide the network services to the subscribers and their users
Connectivity-oriented Interconnection (CoIx): physical and logical linking of carriers and service providers based on
simple IP connectivity irrespective of the levels of interoperability
control plane: plane that has a layered structure and performs the call control and connection control functions; it deals
with the signalling necessary to set up, supervise and release calls and connections
flow (of IP packets): traffic associated with a given connection-oriented, or connectionless, packet sequence having the
same 5-tuple of source address, destination address, Source Port, Destination Port, and Protocol type
forwarding: process of relaying a packet from source to destination through intermediate network segments and nodes
NOTE: The forwarding decision is based on information that is already available in the routing table. The
decision on how to construct that routing table is the routing decision.
IP Television (IPTV): operator controlled IP based TV service
NOTE: IPTV is a cable/satellite replacement service that uses multicast over a private IP network.
network Control Centre: equipment at OSI Layer 2 that controls the access of terminals to a satellite network,
including element management and resource management functionality
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8 ETSI TS 102 855 V1.1.1 (2011-03)
Next Generation Network (NGN): packet-based network able to provide services including Telecommunication
Services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related
functions are independent from underlying transport-related technologies
NOTE: It offers unrestricted access by users to different service providers. It supports generalized mobility,
which will allow consistent and ubiquitous provision of services to users. See ETSI [i.3] and ITU [7].
new generation network: See Next Generation Network.
nomadicity: device that is not fixed but is not continuously mobile
NOTE: A nomadic devices changes locations but tends to stay at a new location for an extended amount of time.
Examples include laptops and netbooks.
Over-The-Top (OTT): IP based video sent on the public Internet without operator control
Service-oriented Interconnection (SoIx): physical and logical linking of NGN domains that allows carriers and
service providers to offer services over NGN (i.e. IMS and PES) platforms with control and signalling (i.e. session-
based), which provide defined levels of interoperability
user plane: plane that has a layered structure and provides user information transfer, along with associated controls
(e.g. flow control, recovery from errors, etc.)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
(NGN)-GETS Government Emergency Telecommunications Services (NGN is GETS with NGN)
(x)DSL Digital Subscriber Line
NOTE: x means the different flavours of DSL.
rd
3GPP 3 Generation Partnership Project
AF Access Function
AMF Access Management Function
A-RACF Access-Resource Admission Control Function
ARF Access Relay Function
AS Application Servers
ASF Application Server Function
BGCF Breakout Gateway Control Function
BGF Border Gateway Function
BMAC BSM Multicast Access Control
BSM Broadband Satellite Multimedia
BSMN BSM Network
BSMS BSM System
BTF Basic Transport Function
CAMEL Call Management Language (TISPAN)
CLF Connectivity session Location and repository Function
CNG Customer Network Gateway
CNGCF CNG Configuration Function
CoIx Connectivity Oriented Interconnection (TISPAN)
CPE Consumer Premise Equipment
CPN Customer Premises Network
CSCF Call Server Control Function
DHCP Dynamic Host Configuration Protocol
DNS Domain Name Service
FoIP Fax over IP
FSS Fixed Satellite Services
GETS Government Emergency Telecommunications Services
GW Gateway
HSS Home Subscriber Server
IBCF Interconnection Border Control Function
I-CSCF Interrogating CSCF
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9 ETSI TS 102 855 V1.1.1 (2011-03)
ID IDentity
IETF Internet Engineering Task Force
IMS Internet Multimedia Subsystem
IMS-AF (IMS) Application Function
IMS-SD (IMS) Service Discovery
IP Internet Protocol
IPTV Internet Protocol TeleVision
IPTV Internet Television
IPv4 Internet Protocol version 4
IPv6 Internet Protocol version 6
ISC IMS Service Control
ISP Internet Service Provider
IWF Interworking Function
M2M Machine to Machine
MAC Medium Access Control
MGCF Media Gateway Controller Function
MGF Media Gateway Function
MGW Media GateWay
MRFP Media Resource Function Processor
NACF Network Access Configuration Function
NAS Network Access Server
NASS Network Attachment Subsystem
NAT Network Access Translation
NCC Network Control Centre
NGN Next Generation Network
NGN Next Generation Network or New Generation Network
NMC Network Management Centre
NOC Network Operation Centre
NSS Network Support System
OBP On-Board Processing
OSA Open Service Access (3GPP)
OSS Operational Support System
OTT Over the Top
PBNM Policy Based network Management
PCRF Policy and Charging Rule Function
P-CSCF Proxy CSCF
PDBF Profile Data Base Function
PDP Policy Decision Point
PES Policy Enforcement Subsystem
PPP Point-to-Point Protocol
PSTN Public Switched Telephone Network
QID Queue Identifier
QOE Quality of Experience
QoS Quality of Service
RACS Resource and Admission Control Subsystem
RCEF Resource Control Enforcement Function
RTP Real Time Protocol
SBP Service-Based Policy control
S-CSCF Serving CSCF
SD Satellite Dependent
SDAF Satellite Dependent Adaptation Functions
SDP Session Description Protocol
SGF Signalling Gateway Function
SI Satellite Independent
SIAF Satellite Independent Adaptation Functions
SIP Session Initiation Protocol
SI-SAP Satellite Independent Service Access Point
SI-SAP Satellite Independent Service Access Point
SLF Subscription Locator Function
SOIX Service Oriented Interconnection (TISPAN)
SPDF Service-based Policy Decision Function
ST Satellite Terminal
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10 ETSI TS 102 855 V1.1.1 (2011-03)
STB Set-top Box
TETRA Terrestrial Trunked Radio
TISPAN Telecommunications and Internet converged Services and Protocols for Advanced Networking
TMF Telecommunications Management Forum
TTL Time to live (protocol timer)
UAAF User Authentication and Authorization Function
UDP User Datagram Protocol
UE Use Equipment
UPSF User Profile Server Function
URI Uniform Resource Identifier
UT User Terminal
VoIP Voice over IP
XoIP "Anything" over IP
4 NGN Impacts on BSM Networks
4.1 Background
The Next Generation Network (NGN) is intended to support a set of assured (and best-effort) end-to-end services over a
network composed of heterogeneous sub-networks, and based on the Internet Protocol (IP).
One of the main characteristics of the NGN architecture is the uncoupling of services and underlying transport functions
(i.e. network technologies), allowing services and transport to be offered separately and to evolve independently.
Therefore in the NGN architectures there is a clear separation between the functions for services and for networks, and
open interfaces are provided between them. Provisioning of existing and new services can then be independent of the
transport network and the access technology. In addition the "external" network services are allowed to use their native
protocols as was specified in the NGN architecture and interwork with other networks over standardised interfaces and
interworking modules. This facilitates the inclusion of more networks, from cable to 4G, within the NGN infrastructure.
The approach adopted by the NGN is shown in figure 4.1.
Other characteristics of the NGN defined by TISPAN concern the management of overall services and networks
(Network Management) through an Operational Support System (OSS). The BSM features required for compatibility
with the NGN OSS have been defined in the TS 102 672 [4] on BSM Management and will not be expanded further
here.
ITU-T (SG-13), ETSI (TISPAN), IETF and 3GPP have defined NGN networks and services and the work on this
subject is continuing (see the informative reference list). There are differences between the details of NGN definitions
(including architectures) of the standards organisations; for example, ES 282 007 [6] on the Core IMS Functionality of
TISPAN is a subset of the 3GPP UMTS Architecture defined in TS 123 002 [i.4] and is restricted to session control
functionalities. In turn the TISPAN session control was adopted by 3GPP.
See annex A for further details of the IMS architecture.
The core IMS excludes Application Servers (AS) that host Access Functions (AF) and transport/media related functions
such as the Multimedia Resource Function Processors (MRFP) and the IMS Media Gateway function (IMS-MGW) that
are service or network specific. Nevertheless, there is a specific set of features and generally common understanding
and convergence across the core functionality, and much of the work on standards is being pursued under the
responsibility of the ETSI TISPAN WG. In the present document the TISPAN definitions and terminology for NGN are
used. Furthermore the present document is based on the TISPAN release 2 specifications as the BSM system does not
address all issues of mobility.
ETSI
11 ETSI TS 102 855 V1.1.1 (2011-03)

Figure 4.1: NGN Application & Transport Strata
4.2 NGN Network Architecture
Figure 4.2 shows a combined physical and functional overview of the NGN network as defined by ES 282 001 [5]
(NGN Functional Architecture). In the figure the BSM network may take the place of an access transport function
(network).
The functional entities that make up a subsystem may be distributed over network/service provider domains.

Figure 4.2: NGN Functional Architecture
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12 ETSI TS 102 855 V1.1.1 (2011-03)
4.2.1 Service Stratum
The NGN needs to support a wide variety of application services. In the Service Stratum therefore, while IMS (see
annex A for a description) is at the heart of all emerging NGN standards, it is just one of a number of Service Control
Subsystems. Examples of other Service Control Subsystems include for example PSTN emulation (PES) and streaming
services. The IMS was intended for control and delivery of real-time conversational services using SIP-based signalling
but has evolved to support other services like advanced IPTV that require service convergence and nomadicity. The
Service Stratum subsystems that support nomadicity may be distributed between visited and home networks.
In addition to the Service Control Subsystem, the Service Stratum includes a number of common functional entities that
can be accessed by more than one subsystem. These include the:
• User Profile Server Function (UPSF) for common identity management.
• Subscription Locator Function (SLF) for mobile users.
• Application Server Function (ASF) for specific applications.
• Interworking Function (IWF) to integrate legacy networks.
4.2.2 Transport Stratum
IP-connectivity is provided to the NGN customer equipment and to other networks by the Transport Stratum. This
transport layer comprises a Transport Control Sublayer on top of transport processing functions in the access and core
networks. Equivalent functions should exist in the User Equipment.
4.2.2.1 Transport Control Sublayer
The Transport Control Sublayer is further divided in two subsystems that work closely together:
• Network Attachment Subsystem (NASS):
- Manages all aspect of network attachment such as IP address provisioning (e.g. DHCP), network level
user authentication, authorisation of network access and access network configuration.
• Resource and Admission Control Subsystem (RACS):
- In charge of admission control, resource reservation, policy control and NAT traversal.
These two subsystems also provide common interfaces to the Service Stratum for any transport technology used in
access and core networks below the IP layer.
• The RACS provides dynamic policy-based resource control to deliver the QoS required by applications as well
as address mediation and border control capabilities.
• And as mentioned above, the NASS provides attachment control, such as authentication, authorization, and
assignment of IP addresses.
The NASS and RACS functions may be logically distributed between access and core networks, and between visited
and home networks.
Customer interfaces are supported by both physical and functional (control) interfaces, and both are shown in figure 4.2.
No assumptions are made about the diverse customer interfaces and customer networks that may be connected to the
NGN access network. All categories of customer equipment are supported in the NGN, from single-line legacy
telephones to complex corporate networks and are managed by discovery mechanisms and SIP messaging. Customer
equipment may be both mobile and fixed.
Physical transport networks provide the connectivity for all components and physically separated functions within the
NGN. Transport is divided into Access Networks and Core Network, with a Border Gateway linking the two transport
network categories.
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13 ETSI TS 102 855 V1.1.1 (2011-03)
The NGN interface(s) to other networks includes many existing networks, such as the PSTN/ISDN, other NGN, 3GPP
networks, the Public Internet, etc. These interfaces generally employ border gateways at both control and transport
levels. Border gateways may include access to media transcoding capabilities and bearer adaptation. Interactions
between the control and transport functions may take place directly or through the RACS functionality.
4.2.2.2 Transport Processing Functions
Transport processing functions in the access and core networks include functions supporting packet forwarding and
routing. These are:
• Media Gateway Function (MGF):
- The MGF is a translation service that handling the disparate telecommunications networks over the NGN
especially transcoding/mapping between IP and legacy circuit-switched networks.
• Border Gateway Function (BGF):
- The BGF provides media relay for hiding endpoint addresses and prevent bandwidth theft as well as
allowing network access translation and acts as a relay between 2 IP transport domains.
• Resource Control Enforcement Function (RCEF):
- The RCEF implement policy based resource management based on QoS requirements of attached
networks.
• Access Relay Function (ARF):
- The ARF is a relay between user equipment and the NASS; it can insert local configuration information
before forwarding a request to the NASS.
• Signalling Gateway Function (SGF):
- The SGF converts SS7 signalling to IP-based signalling (like SIP).
• Media Resource Function Processor (MRFP):
- Provides specific media capabilities like announcements and conferencing as well as interactive voice
response.
• Access Management Function (AMF):
- The AMF provides an interface between an access network and the NGN access control functions.
• Basic Transport Function (BTF):
- The BTF (also Bearer Transport Function) acts as the bearer function for data and media traffic.
A number of these functions relate to legacy network integration. See annex A for more details.
4.3 Service requirements
4.3.1 General NGN Service Requirements
Apart from the "fundamental capabilities" described above namely packet-based transfer, separation of control
functions and support for a wide range of services, other capabilities offered by the NGN architecture are summarised in
table 4.1.
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14 ETSI TS 102 855 V1.1.1 (2011-03)
Table 4.1: NGN capabilities
Capability Description
Subscriber Nomadicity Decoupling the subscriber from specific access and specific terminal equipment
Application Ubiquity Application availability from any access network. Content 'tuning' to match
access & terminal capabilities
Resource Control Authorization & Availability
Accounting: measuring resource usage, revenue assurance
Policing resource usage; fraud prevention
Subscriber Identity & Authentication Common Model for all devices, access & applications
Service Blending Service Brokering enables applications to provide adaptive behaviours based
upon subscriber events and states
Billing and Settlement Mechanisms Especially beneficial for scenarios crossing multiple providers boundaries.

In the NGN architecture, because of network heterogeneity, network service providers need to perform additional tasks
during the establishment of Internet sessions. These tasks are not conveniently or easily carried out by the application
components themselves. They include application selection and routing services, session authorization services, session
monitoring services, session detail recording and billing, network resource and admission control services, and
integration of complimentary applications or services.
Accordingly, the Session Initiation Protocol (SIP) is becoming more widely used as a common mechanism for
establishing sessions of all kinds. SIP has also become the standard session establishment for IMS. SIP based signalling
is now standard across policy management elements and is widely used in the RACS architecture for call and resource
management. In addition, the TISPAN release 2 [4] contains specifications that allows discovery of devices and
networks that use SIP messaging. As a text-based protocol however SIP can lead to large signalling messages and there
are many mechanisms envisaged for their compression over bottleneck resources especially in wireless network (e.g.
RFC 5049 [i.7]).
4.3.2 BSM-Specific Service Requirements
In order to better identify how and where the NGN architecture and IMS functions a number of use cases are described
in this clause. While representative how offered services they are illustrative in nature and of course not a
comprehensive list.
a) VOIP and convergence;
b) IPTV and IP video:
- Live/linear TV;
- Video on Demand (VoD);
c) Emergency/Disaster Services;
d) Smart Grid/ telemetry.
4.3.2.1 VOIP and convergence
This is the traditional NGN/IMS service and the impetus behind the original architecture. For the BSM network, which
is already all-IP the use of NGN/IMS for voice services completely decouples the BSM network transport from the
VOIP service. For example when a VOIP device registers on the VOIP service via the IMS core the Session Description
Protocol (SDP) part of the message announces the specifics of the device for the transmission including admissible rates
and codecs. Hence while the BSM operator needs to deal with bandwidth requirements, the device specific codecs can
be managed at the IMS level. Since those are the most likely to differ greatly from one offering to another, taking these
out of the satellite operations into the terrestrial network is advantageous. Also using existing gateways, a
BSM-terrestrial-mobile VOIP offering could easily profit from subscriber management and operator federation offered
in the IMS core, even interfacing with Public Switched Telephone Networks in areas where legacy services are still
dominant, an advantage for emergency services (see details below). In addition the provision of a native VOIP service
over BSM may allow standard techniques to be adopted such as SIP compression, voice activity detection and QoS.
ETSI
15 ETSI TS 102 855 V1.1.1 (2011-03)
4.3.2.2 IPTV and IP video
Current IPTV offerings are based on broadband wireline networks most often Digital Subscriber lines (xDSL), But the
expansion of IPTV into underserved areas requires the use of Fixed Satellite Services (FSS) and hence the BSM
networks. In addition, BSM networks will most likely see an upsurge of over the top (OTT) IP video services in the
next few years. For the BSM operator both IPTV (operator controlled) and OTT IP video will look similar in terms of
transport but the business model could be different depending on the relationship of the IPTV operator or the OTT
provider with the BSM operator. In addition, the use of cell phone and smartphones for IPTV interactivity is gaining
more and more momentum and should be factored in any BSM IPTV scenario and provide further justification for using
IMS to federate heterogeneous networks.
For video based services, there are many scenarios that can be defined but the most likely ones are:
1) IPTV/IP video over BSM with terrestrial PC or phone interaction;
2) IPTV/IP video over BSM with interaction over BSM network(s); and
3) IPTV/IP video over BSM with interactivity over Mobile Satellite Service.
The most likely of these is 1), but the actual scenarios remain similar.
With multiple codec technologies and rendering devices co-existing in today's video ecosystem, the use of IMS, as in
the case of VOIP allows the BSM network operator to concentrate on IP transport aspects and leave issues of
encryption, transcoding, conditional access and right management to the IPTV operator or IP content provider.
Common identity management across heterogeneous xDSL, BSM and other terrestrial broadband networks is also an
advantage especially when new services incorporating web services (widgets for weather and traffic) and interactivity
(via phone texting or Twitter) are involved. In that case the IMS network acts as the meeting point and the service
broker for all services and enables converged applications like social TV to be deployed. The use of NGN policy
management also enables to decide which sessions to admit in the IPTV system based on delay or bandwidth
restrictions. The location of the policy decisions in the BSM networks will have an influence on the IPTV and IP video
quality of experience (QoE).
4.3.2.3 Live/linear TV
Live TV is currently most likely a multicast service using MPEG-4 codecs (of many profiles) over User Datagram
Protocol directly or with the Real Time Protocol (RTP) over UDP. With IMS, the role of the BSM operator is to
allocate enough resources for the IPTV session and to control QoS elements, like overall delay, especially for
interactive applications. The BSM operator does not have to deal with application level requirements.
4.3.2.4 Video on Demand (VoD)
For BSM networks, VoD services are not greatly different than linear TV services except that VoD is more likely to
have less stringent QoS requirements. But it is also well known that VoD will soon be a multiscreen and multinetwork
offering. Hence the use of the IMS functions allows the BSM networks to deliver VoD services without the need to
provide device-specific codecs and operator or content provider-spec
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