ETSI TS 185 003 V2.0.0 (2008-03)

Technical Specification
Telecommunications and Internet converged Services and
Protocols for Advanced Networking (TISPAN);
Customer Network Gateway (CNG)
Architecture and Reference Points

2 ETSI TS 185 003 V2.0.0 (2008-03)

Reference
DTS/TISPAN-05012-NGN-R2
Keywords
architecture, gateway, IMS, interface, network
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ETSI
3 ETSI TS 185 003 V2.0.0 (2008-03)
Contents
Intellectual Property Rights.5
Foreword.5
Introduction .5
1 Scope.6
2 References.6
2.1 Normative references.6
2.2 Informative references.7
3 Definitions, symbols and abbreviations .7
3.1 Definitions.7
3.2 Abbreviations.8
4 The CNG Architecture .9
4.1 Introduction .9
4.2 CPN and NGN side requirements.9
4.2.1 Analog phone connected to the NGN through a CNG.9
4.2.2 IMS Customer Network Device connected to the NGN through a CNG.10
4.2.3 SIP-non IMS Customer Network Device connected to the NGN through a CNG .11
4.3 CNG functions.12
4.3.1 The transfer level functions .12
4.3.1.1 CNG-NFF: CNG-NAPT and Firewall Function .12
4.3.2 The transport level functions .13
4.3.2.1 CNG-CSMF: CNG-Communication Services Media Function .13
4.3.2.2 CNG-IPTVF: CNG-IPTV Function.13
4.3.3 The CNG Network Attachment Subsystem entities (CNG-NASS) .13
4.3.3.1 CNG-CMF: CNG-Configuration and Management Function.13
4.3.3.2 CNG-AtF: CNG-Attachment Function.13
4.3.3.3 CNG-PCF: CNG-Policy Control Function.13
4.3.3.4 CNG-AuF: CNG-Authentification Function.14
4.3.3.5 CNG-LF: CNG-Location Function.14
4.3.4 The CNG-Resource and Admission Control Functional entities (C-RACF) .14
4.3.4.1 CNG-ACF: CNG-Admission Control Function.14
4.3.5 The CNG-Service-related Functional entities (CNG-SF) .14
4.3.5.1 VGCF: Voice Gateway Control Function .14
4.3.5.2 CNG-SIP Proxy B2BUA Function .15
4.3.5.3 CNG-PPF: CNG-Plug and Play Function .15
4.3.5.4 CNG-UIF: CNG-User Interface Function.15
4.3.5.5 ISIM module.16
5 The CNG Reference points .16
5.1 CND side Reference points .16
5.1.1 Network attachment reference points .16
'
5.1.1.1 e reference point .16
'
5.1.1.2 e reference point .17
5.1.1.3 a reference point.17
u
5.1.2 Transport level reference points.17
5.1.2.1 D reference point .17
j
5.1.3 Service-related reference points.17
'
5.1.3.1 G reference point .17
m
5.1.3.2 u reference point.18
5.1.3.3 C reference point.18
5.2 NGN side Reference points.18
5.2.1 Network attachment reference points .18
5.2.1.1 e reference point.18
5.2.1.2 e reference point.18
5.2.2 Service-related reference points.19
ETSI
4 ETSI TS 185 003 V2.0.0 (2008-03)
5.2.2.1 G reference point.19
m
5.2.2.2 U reference point .19
t
6 The CNG Data Model .19
7 Information flows.19
7.1 Attachment flows .20
7.2 Configuration and management flows.20
7.3 Signalling flows.21
7.3.1 CND attachment and local/IMS registration.21
7.3.2 Outgoing call.22
7.3.2.1 SIP non-IMS CND.22
7.3.2.2 IMS CND.23
7.3.3 Internal call .24
7.3.4 Admission Control.24
7.4 Remote Access flows .25
7.4.1 Remote Access Connection Set-up.25
7.4.2 Download of content using HTTP .26
7.4.3 Upload of content using HTTP.28
Annex A (informative): Bibliography.30
History .31

ETSI
5 ETSI TS 185 003 V2.0.0 (2008-03)
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 Telecommunications and Internet
converged Services and Protocols for Advanced Networking (TISPAN).
Introduction
The present document defines Release 2 of an anticipated series of releases of TISPAN NGN. Release 2 extends the
capabilities of Release 1, enhances some Release 1 capabilities and provides some new services. The TISPAN NGN is
described in terms of the content capabilities and this release (Release 2) is defined by the documentation set and the
features that these support.
Clause 4 provides a general description of an NGN, and the TISPAN Release 1 NGN in particular. The general
objective of Release 2 is to extend Release 1 through enhancements and new services. The present document focuses on
additional capabilities and services and continues to enable an NGN to be a flexible platform allowing future
enhancements and releases.
The TISPAN NGN is specified using a release mechanism. The present document provides an overview of the
capabilities in the second release. No assumptions should be made about future releases.
Throughout the present document, references to NGN are assumed to be references to TISPAN NGN unless otherwise
indicated.
ETSI
6 ETSI TS 185 003 V2.0.0 (2008-03)
1 Scope
The present document provides an overview of Customer Network Gateway (CNG) functional architecture and
reference points and the way it interacts with an NGN, as described in ETSI TISPAN Release 1 and Release 2 standards
(see ES 282 001 [1]).
The present document describes architectural building blocks to be included in the CNG to support the interworking
with an NGN, both at the transfer, transport and service layers. It also defines the reference points between the CNG
internal architectural blocks involved and a CND.
The WG5 does not address the layer 1 issues, as such studies refer to the AT&TM Group.
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.
For online referenced documents, information sufficient to identify and locate the source shall be provided. Preferably,
the primary source of the referenced document should be cited, in order to ensure traceability. Furthermore, the
reference should, as far as possible, remain valid for the expected life of the document. The reference shall include the
method of access to the referenced document and the full network address, with the same punctuation and use of upper
case and lower case letters.
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.
[1] ETSI ES 282 001: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Functional Architecture".
[2] ETSI ES 282 003: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Resource and Admission Control Sub-system (RACS);
Functional Architecture".
[3] ETSI ES 282 004: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Functional Architecture; Network Attachment
Sub-System (NASS)".
[4] ETSI ES 282 007: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); IP Multimedia Subsystem (IMS); Functional architecture".
ETSI
7 ETSI TS 185 003 V2.0.0 (2008-03)
[5] ETSI ES 283 003: "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]".
[6] ETSI TS 182 012: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); IMS-based PSTN/ISDN Emulation Subsystem; Functional
architecture".
[7] ETSI TS 183 019: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Network Attachment; User-Network Interface Protocol
Definitions".
[8] IETF RFC 3261: "SIP: Session Initiation Protocol".
[9] IETF NAPT traversal Working Groups: BEHAVE for STUN TURN methods, MMUSIC for ICE,
SIP for SIP Outbound.
[10] ETSI TS 131 103: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Characteristics of the IP Multimedia Services Identity
Module (ISIM) application (3GPP TS 31.103)".
[11] IETF RFC 2131: "Dynamic Host Configuration Protocol".
[12] ETSI TS 124 229: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); 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 8.2.0 Release 8)".
[13] ETSI TS 185 006: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); TISPAN Customer Devices architecture and interfaces".
2.2 Informative references
[14] ETSI TR 185 007: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Analysis of protocols for customer networks connected to
TISPAN NGN".
[15] ETSI TR 185 004: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); High level customer network architectures".
[16] HGI Forum TR-069: "CPE WAN Management Protocol".
[17] HGI Forum TR-098: "Data Model for TR6069".
[18] HGI Forum TR-104: "Provisioning Parameters for VoIP CPE".
[19] ETSI TS 185 005: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Services requirements and capabilities for customer networks
connected to TISPAN NGN".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
CPN Device: device that is physically installed in the CPN allowing user access to network services; this can be a
Customer Network Gateway with gateway functionalities towards the NGN, or a Customer Network Device being the
end user terminal
ETSI
8 ETSI TS 185 003 V2.0.0 (2008-03)
Customer Network Device (CND): CPN device enabling the final user to have direct access to services through a
specific user interface
NOTE: CNDs can be dedicated to the internet, conversational and audio-video services. But they could be also
Consumer Electronics equipment and other devices which may have nothing to do with these premium
services (e.g. services performing a content sharing within a CPN, typically between a PC and a music
system).
Customer Network Gateway (CNG): CPN device acting as a gateway between the CPN and the NGN
NOTE: CNG is able to perform networking functions from physical connection to bridging and routing
capabilities (L1-L3), but also possibly implementing functions related to the service support (up to L7).
Customer Premises Network (CPN): in-house network composed by customer network gateway, customer network
devices, network segments, network adapters and nodes
NOTE: Network segments are physical wired or wireless connections between customer premises network
elements); network adapters are elements performing a L1/L2 conversion between different network
segments; nodes are network adapters with L3 routing capabilities.
IMS CND: CND whose external behavior complies with the IMS specifications
NOTE: See [1], [2], [3], [4] and [5].
"Multiple" Play Services (can be: double, triple, quadruple etc.): delivery by a single service provider of different
types of concurrent services to one or multiple users within the same CPN
NOTE: Services can be categorised in the following way: data (e.g. Web browsing, best effort traffic etc.),
person(s) to person(s) communication, entertainment.
Non-IMS SIP IETF CND: SIP-based CND whose external behavior conforms to RFC 3261 [8] but do not fully
conform to the IMS specifications
Many scenarios are expected to provide one service from a service provider to a customer device (case of multiple
service providers, one or several CNG, etc.). They are presented within the TR 185 004 [15] and TS 185 005 [19].
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACS Auto-Configuration Server
AKA Authentication and Key Agreement
ALG Application Layer Gateway
A-MGF Access-Media Gateway Function
ARF Access Relay Function
B2BUA Back-to-Back User Agent
CLF Connectivity session Location and repository Function
CND Customer Network Device
CNG Customer Network Gateway
CNG-ACF CNG-Admission Control Function
CNG-AtF CNG-Attachment Function
CNG-AuF CNG-Authentication Function
CNGCF CNG Configuration Function
CNG-CMF CNG-Configuration and Maintenance Function
CNG-CSMF CNG- Communication Services Media Function
CNG-LF CNG-Location Function
CNG-NFF CNG-NAPT and Firewall Function
CNG-PCF CNG-Policy Control Function
CNG-PPF CNG-Plug and Play Function
CNG-UIF CNG-User Reference point Function
CPN Customer Premises Network
ETSI
9 ETSI TS 185 003 V2.0.0 (2008-03)
DHCP Dynamic Host Configuration Protocol
NOTE: http://www.ietf.org/rfc/rfc3235.txt?number=2131
EF Elementary Files
ETH Ethernet
IMS IP Multimedia Subsystem
ISIM IMS Subscriber Identity Module
ISIM IMS Subscriber Identity Module
MGC Media Gateway Controller
NACF Network Access Configuration Function
NAPT Network Address and Port Translation
NOTE: http://www.ietf.org/rfc/rfc3235.txt?number=3235

NASS Network Attachment Subsystem
P-CSCF Proxy Call Session Control Function
PLT Power-Line Telecommunication
SIP Session Initiation Protocol
SSID Service Set Identifier
UE User Equipment
UICC Universal Integrated Circuit Card
VGCF Voice Gateway Control Function
4 The CNG Architecture
4.1 Introduction
The following clauses present the functional entities for the CNG. Examples of Customer Network Devices may be
connected to the CNG:
a) Analog phones connected through the CNG to the NGN network.
b) IMS Customer Network Devices connected through a CNG to the NGN network [5].
c) Non IMS SIP IETF Customer Network Devices [7].
d) ISDN Customer Network Devices through the CNG to the NGN network.
Different types of Customer Network Devices may be involved in Intra CPN communication through a CNG.
The list of Customer Network Devices which are likely to be connected to the CNG is provided by the TS 185 006 [13].
The general overview of the CPN Architecture is provided by the TR 185 004 [15]. The CNG functional entities are
described in the following parts of the document, as well as the reference points between each function.
4.2 CPN and NGN side requirements
The list of the CNG requirements is provided by the TS 185 005. specification for Service requirements and capabilities
for customer networks connected to TISPAN NGN.
4.2.1 Analog phone connected to the NGN through a CNG
In this case, the CNG includes all the CPN functionalities necessary to fulfill a service between the analog phone and
the NGN, as shown in figure 1.
ETSI
10 ETSI TS 185 003 V2.0.0 (2008-03)

TThhee C CPPN N EEnnvviiroronnmmeenntt tthhee NNGGN anN andd I IMMS enS enttiittiieess
CCuustostommeerr N Neetwtwoorrkk GaGatetewwaayy
CNGCNG
UU
tt ASAS
ZZ
VVooiicce Ge Gaatewtewaayy CControntrooll F Funcunctitionsons ((VVGGCCFF))
P-P-CCSSCCFF
GG
mm
UIUICCCC
AAnalnalogog
ISISIIMM
CNDCND
DD
jj
CCNNGG--CCoommummuniniccaatitionon Ser Servviicceess MMediediaa F Fuuncncttiioonn ((CCNNGG--CCSSMMFF))
AAcceccessss n nooddee
CCNNGG--IPIPTTVV F Fuunncctitiononss ((CCNNGG--IPIPTTVVFF))
ee
CCNNGG--PPoolliiccyy Co Connttroroll Fu Funnccttiioonn (C(CNGNG-P-PCF)CF)
CNCNGGCCFF
CCNNGG--CCoonnffiigurguratiation & Manon & Manaaggeemmeent Fnt Fuunncctitionon ((CCNNGG--CCMMFF))
ee
ARARFF
CCNNGG--LoLoccaattiioonn F Funcuncttiioonn ((CCNNGG--LLFF))
CNCNGG--AAttttaacchhmemenntt FFuunnccttiioonn ((CNGCNG--AAttFF))

Exchanges inside the CNG
Network attachment functions
Transport plane functions
Service plane and applicative functions

Figure 1: Analog phone connected to the NGN-IMS network through a CNG
4.2.2 IMS Customer Network Device connected to the NGN through a
CNG
In this case, the Customer Network Device includes all the CPN functionalities necessary to fulfill a service between
itself and the NGN-IMS network, as shown in figure 2.
ETSI
11 ETSI TS 185 003 V2.0.0 (2008-03)

LALAN sN siiddee : : WAWANN s siiddee : :

ththee U Usserer EqEquuiippmmenentt thethe NG NGN N aannd Id IMMSS
eenntitititieess
CuCussttoommeerr N Neetwtwoorrkk G Gaatetewwaayy
CNGCNG
uu
CCNNGG--UUsseerr In Inteterrffacacee FFuncunctitionon ((CCNNGG--UUIIFF))
CCuussttoommeerr Ne Nettwwoorrkk De Devviiccee
CCNNGG--PlPlug ug andand P Pllaayy F Fuuncnctitionon ((CCNNGG--PPPFPF))
CNCNDD
CNG-CNG- SSIIPP   pr proxoxyy B2 B2BUBUAA
CC
CCNNDD--PPllug andug and Pl Plaayy F Fuuncnctitionon ((CCNNDD--PPPFPF)) UICCUICC
SISIPP
RRegiegissttrraarr
ISIISIMM
PrProoxxyy
GG ''
mm
CCuussttomomerer P-P-CCSSCCFF
CNCND-D-SSIIPP U UAA
AApppplicalicattioionn
CuCussttoommeerr
B2B2BBUUAA
GG GG
AApppplicalicattioionn
mm mm
CuCussttoommeerr
GG
mm
AApplppliiccatiatioonn
CCNNDD--SSeellff P Prrovoviissiionioningng ((CCNNDD--SSP)P) ASAS
UU
tt
UU
CCNNDD--CCoommmmuniuniccaatitionon S Seerrvviicceses MeMedidia a
tt
CCNNGG--NNAAPPTT and F and Fiirreewwaallll F Fuuncnctitioonn ((CCNNGG--NNFFFF))
FFuncunctitionon ((CCNNDD--CCSSMMFF))
CNCND-D-NANAPPTT Tr Traavveerrssaall FFuunnccttiioonn (C(CNDND-N-NTF)TF)
DjDj
UIUICCCC CCNNGG--IIPPTTVV F Fuunnccttiioonnss (C(CNGNG-I-IPPTTVVFF) )
CCNNDD--CCoonfinfigguurraattiioonn & & ManManageagemmentent AAcccecessss n nooddee
FFuncunctitionon ((CCNNDD--CCMMFF))
ISISIIMM
ee
CCNNGG--AAdmdmiissssiionConConontrtrololFFuncunctitionon ((CCNNGG--AACCFF))
ee ''
CCNNDD--LoLoccaall A Auutthhenenttiiccaatitioonn FFuuncncttiioonn ((CCNNDD--LLAFAF))
CNCNGG--PPoolliiccyy Co Connttroroll FuFunnccttiioonn (C(CNGNG-P-PCCFF))
ee
CNDCND--AAttttaacchhmmeenntt FFuunnccttioionn ((CNCND-AD-AttF)F) CNCNGGCCFF
CCNNGG--CCoonfinfigguurraattiion & Maon & Managemnagemenent t FFuuncnctitioonn ((CCNNGG--CCMFMF))
aa
uu
CCNNGG--AAuuththententiiccaattiioonn FFununccttiioonn ((CCNNGG--AAuuFF)) ARARFF
ee
ee ''
CCNNGG--AttAttaacchhmmeentnt FFuncunctitionon ((CCNNGG--AAtFtF))
ee
CCNNGG--LLooccaatition Fon Fuuncnctitionon ((CCNNGG--LLFF))
LANLAN WWAANN
Exchanges inside the CNG
Network attachment functions
Transport plane functions
Service plane and applicative functions

NOTE: The IMS CND functions are described within the TS 185 006 [13] dedicated to Customer Network Devices.

Figure 2: IMS Customer Network Device connected to the NGN-IMS network through a CNG
4.2.3 SIP-non IMS Customer Network Device connected to the NGN
through a CNG
In this case, the Customer Network Gateway includes all the CPN functionalities necessary to fulfill a service between
itself and the NGN-IMS network, as shown in figure 3.
ETSI
12 ETSI TS 185 003 V2.0.0 (2008-03)

LALANN si sidede : : WAWANN s siiddee : :

the Uthe Usserer EEqquiuipmentpment tthhee NG NGN aN anndd IIMMS S
entitieentitiess
CuCussttoommeerr Ne Netwotworrkk GaGatteewawayy
CNCNGG
uu
CCNNGG--UUsser Iner Interterffacacee FFuncunctitionon (C(CNNGG-U-UIFIF))
CuCussttoommeerr Ne Netwotworrkk De Devviiccee
CCNNG-PG-Pllug ug and Pand Pllaayy F Fuuncnctitionon (C(CNNGG-P-PPPFF))
CNDCND
CNCNGG-- SISIP P  pr proxoxyy B B22BBUUAA
CC
UIUICCCC
CCND-ND-PluPlugg a anndd P Pllaayy F Fuunnccttiioonn ((CND-CND-PPFPPF))
SISIP/P/IIMMSS SISIPP
RRegiegissttrarrar
AAdaptedapterr PrProoxxyy ISISIMIM
GG ''
mm
CuCuststoommeerr P-P-CSCSCFCF
CND-CND-SISIP UAP UA
AApppplicalicattioionn
CuCuststoommeerr
B2B2BUABUA
GG
AApppplicalicattioionn
mm
CuCuststoommeerr
GG
mm
AApppplicalicattioionn
CND-CND-SSeelflf P Prroovvisioisionniinngg ((CNDCND--SSP)P) ASAS
UU
tt
UU
CND-CND-CoCommmmuunniicacattiioonn Se Serrvviceicess M Meeddiiaa
tt
CCNNGG-N-NAAPPTT and Fi and Firerewwaallll Fu Funcnctitionon (C(CNNGG-N-NFFFF))
FFuunnccttiioonn ((CND-CND-CSMCSMFF))
CND-CND-NAPNAPTT T Trraavveerrsasall FFuunnccttiioonn ((CND-CND-NTNTFF))
DjDj
CNGCNG--IIPTPTV FV Fuunnccttiioonnss ((CNGCNG--IIPTPTVFVF))
CCNNDD--CCoonnffiiguragurattiioonn & & ManManagemagementent AAcceccess nss nooddee
FFuunnccttiioonn ((CND-CND-CMCMFF))
ee
CCNNGG--AAddmmiissssiionConConontrtrololFFuuncnctitionon (C(CNNGG-A-ACCFF) )
ee ''
CND-CND-LLoocacall Au Autthheennttiiccaattiioonn FFuunnccttiioonn ((CND-CND-LLAAFF))
CNGCNG--PPooliclicyy Co Connttrrool l FFuunnccttiioonn ((CNGCNG--PPCFCF))
ee
CND-CND-AAttttaacchhmmeenntt FFuunnccttiioonn ((CCNNDD--AAttFF)) CNGCNGCCFF
CCNNGG-C-Confionfigguurraattiioonn & & ManagemManagementent Fu Funcnctitioonn (C(CNNGG-C-CMFMF) )
aa
uu
CCNNGG-A-Aututhenhentiticcaatitionon FuncFunctitionon (C(CNNGG-A-AuuFF)) ee ARARFF
ee ''
CCNNGG-A-Attttacachmehmenntt FFuncunctitionon (C(CNNGG--AAtF)tF)
ee
CCNNGG-Loc-Locaattiion Fon Funcunctitionon (C(CNNGG-LF-LF))
LALANN WWAANN
Exchanges inside the CNG
Network attachment functions
Transport plane functions
Service plane and applicative functions

Figure 3: Non IMS SIP Customer Network Device connected to the NGN-IMS network through a CNG
'
In this case G is used, the SIP proxy B2BUA shall perform an adaptation of the non-IMS SIP profile from a CND
m
which requests for an IMS session.
4.3 CNG functions
4.3.1 The transfer level functions
4.3.1.1 CNG-NFF: CNG-NAPT and Firewall Function
The CNG-NFF entity shall provide gate control functionality i.e. dynamic NAPT and firewall functions at the boundary
between the CPN and the NGN.
ETSI
13 ETSI TS 185 003 V2.0.0 (2008-03)
4.3.2 The transport level functions
4.3.2.1 CNG-CSMF: CNG-Communication Services Media Function
The CNG-CSMF is the termination point for the access node, it shall perform an adaptation so as to deliver media flows
from the NGN network to an analog or IP Customer Network Device.
The CNG-CSMF is used for analog (or digital in the case of ISDN CNDs) to IP media conversion - in which case it
corresponds to the R-MGF identified in ES 282 001 [1] or it is used for IP-IP media traffic.
As a result, this functionality is recommended.
4.3.2.2 CNG-IPTVF: CNG-IPTV Function
When supporting IPTV services, the CNG shall be able to forward inbound multicast packets only to the physical
interfaces connected to devices that have joined the specific multicast group. This mechanism should be implemented
acting on layer 2 and layer 3 multicast signaling flows (e.g. IGMP based).
The CNG shall be able to perform a link layer multicast to unicast translation, if the CPN segment, which the IPTV
CND is connected to, is not able to support multicast; specifically, when sending an IP multicast packet to a
host received on an NGN reference point, the CNG can send the packet to the unicast MAC address of the host
(contained in the multicast signalling message without any change in the IP destination address). This mechanism is
also of interest for example when the IPTV CND is connected to the CNG through Powerlines technology (directly or
using ETH-to-PLT bridges).
4.3.3 The CNG Network Attachment Subsystem entities (CNG-NASS)
4.3.3.1 CNG-CMF: CNG-Configuration and Management Function
The CNG-CMF shall manage a mutual authentication between the CNGCF and the CNG.
The CNG-CMF shall enable the CNG configuration and firmware upgrade.
The CNG-CMF entity should enable transmission of configuration information to CNDs, obtained from the CNGCF.
As a result the CNG-CMF should be able particularly to store configuration information dedicated to several CND, after
sending only one request to the CNGCF. As soon as a CND is connected, the CNG-CMF should be able to deliver
configuration parameters to it.
Furthermore, the CNG-CMF should allow maintenance of any CPN device (CNG/CND) from the NGN network,
through the CND-CMF, that is to say the opportunity to do diagnostic and performance tests too. Functionalities should
be added to the CNGCF, whether this latter entity could perform the CPN maintenance.
For instance, the CNG-CMF could provide the functionality and reference points of a DSL Forum Auto Configuration
Client (see TR-069 [16]).
Moreover, the CNG-CMF may be able to perform management activities related to remote access. The remote access
allows the user to access a CND from another device via the Internet through the G reference point, and work on it
m
remotely.
Some authentication parameters may be stored in a UICC (containing the ISIM).
4.3.3.2 CNG-AtF: CNG-Attachment Function
The CNG-AtF entity shall be responsible for allocation of IP addresses to user premises equipment (CND), and to the
CNG from the NACF via the ARF.
4.3.3.3 CNG-PCF: CNG-Policy Control Function
The CNG-PCF may integrate a database containing the access profile.
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This includes bandwidth and QoS parameters for the CNG Customer Network Device side applications and terminals,
which could be configured by a user. For instance, congestion issues within the CPN may be solved defining resources
for several SSID.
4.3.3.4 CNG-AuF: CNG-Authentification Function
The CNG-AuF shall manage the authentication of CNDs to be connected to the CPN. A CND requesting for a CPN
Wireless attachment should be authorized by the access point embedded in the CNG.
The CNG-AuF may thus be configured by the user for such a case, using the CNG-User Interface Function (CNG-UIF).
4.3.3.5 CNG-LF: CNG-Location Function
The CNG-LF functional entity may allow an internal application providing location information, to perform for instance
emergency calls or deliver some local video content.
This information may be configured by the owner of the CNG, received from the CLF or obtained from the network,
via the CNG-AtF (typically through DHCP option 82).
The information should also come from the CLF. In this case the CNG-LF may not be used.
4.3.4 The CNG-Resource and Admission Control Functional
entities (C-RACF)
4.3.4.1 CNG-ACF: CNG-Admission Control Function
The CNG-ACF should receive and send QoS messages from/to the CNG-SIP proxy B2BUA Function. In particular it
should:
a) check resources availability on each link/device involved in the communication requesting a QoS
reservation/allocation, through an internal database;
b) perform the appropriate resources reservation, through the CNG-PCF.
Thus, the CNG-ACF should manage session limitations for instance or the priority of media streams. This applies to
upstream flows but there may also be an opportunity to do so for downstream flows.
4.3.5 The CNG-Service-related Functional entities (CNG-SF)
Depending on the services supported, a CNG may include one or more Service-related Functions. The present version
of the present document identifies four types of SCFs intended to support SIP-based applications. It should be noted that
not all applications require a Service-related Function to be involved (e.g. P2P applications usually do not require such
functions).
4.3.5.1 VGCF: Voice Gateway Control Function
The VGCF within the CNG is the equivalent of an MGC embedding a SIP User Agent. A CNG should include several
UAs in case of multi analog and/or ISDN Customer Network Device within the CPN. The VGCF should control the
CNG-CSMF (i.e. the R-MGF as defined in ES 282 001 [1]).
The VGCF should perform the service authentication and manage signaling flows securely.
NOTE: The VGCF together with the CNG-CSMF provides the function of a R-VGW as defined in
TS 182 012 [6].
In case of AKA authentication, the VGCF shall have access to the authentication parameters through an ISIM/UICC
functionality. To be noticed that HTTP Digest is for an early deployment whereas IMS AKA is the target solution.
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4.3.5.2 CNG-SIP Proxy B2BUA Function
The CNG-SIP Proxy B2BUA should implement:
a) a Local SIP Registrar without any authentication needed;
b) an outbound SIP Proxy, a SIP access point for the P-CSCF, forwarding the register messages to the P-CSCF if
necessary;
Moreover, it may be:
c) a protocol adaptation module performing an adaptation of non-IMS compliant IETF SIP protocols towards one
IMS compliant SIP protocol. This functionality could also be performed by the NGN.
NOTE: Some adaptation may be performed by the CNG so as to support non-IETF SIP CNDs in the CPN
(proprietary SIP) but this case is out of the scope of the present document.
The CNG-SIP Proxy B2BUA Function should be aware of each SIP CND capability within the CPN environment.
The CNG-SIP Proxy B2BUA Function shall at last be able to manage two SIP dialogues and the associated identities
(possibly through an ISIM module), from both the NGN and the CND sides. This gives the opportunity to transfer an
IMS session from a device to another or to forward an incoming call to the appropriate CNDs (forking).
In case of AKA authentication, the SIP Proxy B2BUA shall have access to the authentication parameters through an
ISIM/UICC functionality. To be noticed that HTTP Digest is for an early deployment whereas IMS AKA is the target
solution.
4.3.5.3 CNG-PPF: CNG-Plug and Play Function
The CNG-PPF may obtain some CND information (service discovery, description) and allow their control.
Also, the CNG-PPF should allow a communication between many types of Customer Network Device within the CPN,
not only conversational (based on UPnP for instance).
The CNG-PPF may also support this kind of communication through the CNG between NGN devices and CND
devices.
While facilitating such communication, ALG functionality may be needed by the CNG-PPF, interfacing the CNG-NFF.
Since some of the communication sessions supported by the CNG-PPF result in media sessions, the CNG-PPF may
need to interface the CNG-ACF in order to support QoS provisioning for these types of services.
When sessions (for example UPnP based) are initiated between a CND and a remote NGN device, these sessions may
be established "wrapped" by IMS SIP session establishment and are then described in the SDP parts of the IMS SIP
signalling. When establishing the UPnP session between the NGN and CPN endpoints the CNG-PPF needs to perform
ALG functionality, by re-writing any CPN references within the UPnP messages and also control port forwarding
through the CNG-NFF. Informative flows for the Remote Access feature are detailed in clause 7.4.
4.3.5.4 CNG-UIF: CNG-User Interface Function
The CNG-UIF entity should allow the user to configure many CNG parameters for the transport layer:
a) firewall rules, possibly defined for each user (e.g. parental control);
b) CNDs authorized within the CPN, with possible bandwidth restrictions.
The operator shall be able to prevent a user from modifying a specific subset of CPN parameters.
Thus this entity may have reference points with the CNG-AuF and the CNG-NFF of the CNG.
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4.3.5.5 ISIM module
The ISIM (see figure 4) is a network access application dedicated to IMS access contained in a UICC. It may be
implemented in a CNG.
Figure 4: Example of "UICC Card composition"
The ISIM includes:
a) The IMPI (IMS private identity).
b) At least one IMPU (IMS public Identity).
c) The operator's NGN Domain Name.
d) Support for sequence number checking in the context of the IMS Domain.
e) The same framework for algorithms as specified for the USIM applies for the ISIM.
f) An authentication element so as to support the AKA authentication.
The ISIM is located in the ISIM Application Dedicated File (ADFISIM) and contains service and network related
information. The ADFISIM provides various data contained in Elementary Files (EF), for instance the EFIMPI
containing the private user identity. Details about this file structure can be found in TS 131 103 [10].
5 The CNG Reference points
5.1 CND side Reference points
5.1.1 Network attachment reference points
'
5.1.1.1 e reference point
The e ' reference point is defined between the CND and the CNG-AtF. The CNG-AtF provides IP addresses (IPv4 or
IPv6 format) to the CND through the CND-AtF, it may also send some configuration information for the CND
(typically through DHCP).
The CND and CNG shall mutually exchange their identities (e.g. MAC address, DeviceID, etc.) on e ' reference point.
The CNG has to know which CNDs are behind itself within the CPN and each CND has to know its CNG.
This reference point is mandatory if the CNG runs in a routed mode
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'
5.1.1.2 e reference point
The e ' reference point is defined between the CND and the CNG-CMF. The CNG-CMF may provide the CND with
parameters that are pre-configured in the CNGCF and sent to
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