International Telecommunication Union
Functional Architecture Model of
NGN
Naotaka MORITA
Vice Chairman of SG13, ITU-T
Senior Research Engineer, Supervisor
NTT Service Integration Labs.
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
Characteristics of Next Generation Networks (Y.2011)
Service-related functions and transport functions are separated into two strata
• Transport functions assume packet-based integrated networks
— The currently widely used IP protocol is the core protocol.
• Service-related functions refer to basic and additional telephone connection functions and the
provision of functions inherent to services such as WWW and video distribution
— Initial studies focused on session control functions for the implementation of IP telephony,
video chat, and video-conferencing using the SIP protocol as the core protocol.
• The NGN separation model supports new independently developed technologies
and flexible system deployment and permits the formation of various
businesses
Video Services (TV, movies, etc.)
Data Services (WWW, e-mail, etc.)
(Any/All Applications
e.g., voice, data, video)
Telephone Services
NGN Service-Related Functions
Anything and Everything
Internet Protocol
(IP)
Everything
Scope
of the
Internet
“Service Stratum”
NGN Transport Functions
(Any and All Network Technologies)
“Transport Stratum”
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
2
NGN architecture overview (Rec. Y.2012)
Applications
ANI
Management Functions
Application Support Functions & Service Support Functions
Service User
Profiles
Service Control
Functions
Service stratum
Network Attachment
Control Functions
Transport User
Profiles
End-User
Functions
Resource and
Admission
Control Functions
Other
Networks
Transport Control Functions
Transport Functions
UNI
NNI
Transport stratum
Control
Media
Management
Note:ITU-T/ITU-D
UNI/NNI/ANI
are not meant to represent any specific interfaces.
Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
3
SIP: Unique features of interactive end-to-end
communication
Interactive communication
(e.g., IP telephony)
Web browsing
SIP server
Web server
Far end
Near end
Far end
Near end
Web browsing
Communication
mode
Interactive communication
Machine
Far end example
General public
Fixed and easy to know
Far end IP address
Fluid and hard to know in advance
User always originates
communication
Communication
initiation
User may be invited to
communication
Near end selects from a list
provided by far end
Application to be
used
Room for negotiation,
e.g., codec type
Always available
Far end availability
Uncertain
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
4
SIP: Support for end-to-end communication
SIP server
SIP signalling
Media stream
Communication
mode
Interactive communication
Functions achieved by session control (SIP)
Far end example
General public
Far end
IP address
Fluid and
hard to know in advance
o Registration to prepare for receiving a session
Communication
initiation
User may be
invited to communication
o Support of session initiation (INVITE) and
Application
to be used
Room for negotiation,
e.g., codec
Far end
availability
Uncertain
o Identification with unique user name (URI)
(REGISTER)
o User authentication to validate the user
termination (BYE)
o Negotiation of communication means (offer and
answer by SDP)
o Proxy on behalf of user, providing alternate
method
o Presence to inform availability in advance
o Instant messaging
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
5
IMS: What is IMS (IP Multimedia Subsystem)?
IMS
IMSis
isaasubsystem
subsystemproviding
providingcall
callprocessing
processingand
andaavariety
varietyof
ofmultimedia
multimedia
services
servicesin
inan
anIP-based
IP-basedpacket-switching
packet-switchingdomain.
domain.
zz Provides
Providesvoice,
voice,video,
video,presence,
presence,messaging,
messaging,conferencing,
conferencing,and
andother
other
services
services
zz Complies
Complieswith
withIETF
IETFstandardized
standardizedsession
sessioncontrol
control(SIP);
(SIP);profiling
profiling
zz Independent
Independentof
ofaccess
accessnetwork
network
zz Application
Applicationservice
serviceplatform
platformitself
itselfis
isoutside
outsidethe
thescope
scopeof
ofIMS
IMS
Application
Application service
service platform
platform
Other
Other IP
IP
networks
networks
IMS
(SIP)
(SIP)
PSTN/ISDN
PSTN/ISDN
IP
IP transport
transport network
network
(IP-CAN)
(IP-CAN)
IP-CAN: IP Connectivity Access Network
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
6
NGNs Based on IMS (Rec. Y.2021)
• Architecture centers on SIP proxy-equivalent Call Session Control Functions (CSCFs).
• Employs a separation model that decouples media processing elements and their controlling
elements.
• Links to transmission systems through a Gq interface.
Rf/Ro
Charging
Functions
Ut
AS-FE
Sh
Dh
SUP-FE
ISC/Ma
SAA-FE
SL-FE
Dx
Cx
Network
Attachement
Control
Function
NSIW-FE
Ib
Mw
IBC-FE
Mx
Ic
I/S-CSCF
« Core IMS»
Mi
BGCF
Mr
e2
Mx
Mk
P-CSCF
Mx
Rs
Mg
MRFC
MGCF
Ie
Mp
Mn
PSTN/ISDN
Rs
SG-FE
IP Networks
Mw
Mj
Gm
Iw
Rf/Ro
AS:
BGCF:
CSCF:
HSS:
IP-CAN:
ISC:
MGCF:
MGW:
MRFC:
MRFP:
P-CSCF:
SLF:
Application Server
Breakout Gateway Control Function
Serving CSCF
Home Subscriber Server
IP-Connectivity Access Network
IMS Service Control Interface
Media Gateway Control Function
Media Gateway
Multimedia Resource Function Controller
Multimedia Resource Function Processor
Proxy CSCF
Subscription Locator Function
Resource and Admission Control Function
MRP-FE
TMG-FE
UE
IP Transport (Access and Core)
IBG-FE
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
7
Roaming Implementation with Proxy CSCF
• In IMS nomenclature, the SIP proxy function is called the Call Session Control Function
(CSCF).
• IMS defines a mobile-destination (roaming-destination) SIP server (proxy CSCF) in addition
to the subscribing SIP server (serving CSCF) to allow authentication and QoS control by the
mobile-destination network.
• IMS presumes that the serving CSCF cannot be accessed directly (a walled garden).
B’s Home Network
(Tokyo)
A’s Home Network
(London)
Serving
Serving
CSCF
CSCF
HSS-1
HSS-2
A’s Present Location
(Dar-es Salaam)
Control signal
Voice, images,
or other media
Serving
Serving
CSCF
CSCF
B’s Present
Location
(Geneva)
Proxy
Proxy
Proxy
CSCF
CSCF
Proxy
CSCF
CSCF
B
A
IP Backbone
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
8
Applications
ANI
Management functions
Application Support Functions & Service Support Functions
(may include own Authentication, Authorization and Accounting)
Service
control
S-5: S. User
Profile FE
S-6: S.
Authentication &
Authorization FE
S-14: Media
Resource Broker FE
S-12: Network
Signaling
Interworking FE
S-3: Interrogating Call
Session Control FE
S-4: Subscription
Locator FE
S-15: General
Services Control FE
S-2: Proxy Call Session
Control FE
S-11: User Signaling
Interworking FE
S-1: Serving
Call Session Control FE
S-8: Access GW
Control FE
S-13: Media Resource
Control FE
NACF
RACF
T-15: Home GateWay
Configuration FE
T-12: T. User
Profile FE
T-13: T. Location
management FE
Application
*
S-7: Interconnection
Border Gateway
Control FE
S-10: Breakout
Gateway Control
FE
S-9: Media
GW
Control FE
RACF
T-16: Policy Decision FE
Other NGN
IP
Multimedia
Networks
T-16: Policy Decision FE
T-17: Transport
Resource Control FE
T-17: Transport
Resource Control FE
NGN
End-User UNI
Function
T-11:
T. Authentication
&Authorization
FE
Legacy
Terminal
T-4: Access
Relay FE
Customer
Network
T-2: Access
Node FE
Legacy
Terminal
Core transport
T-8:
Media
Resource
Processing
FE
T-14: Access Management FE
RGW
NGN
Terminal
T-10:
Network Access
Configuration FE
T-1: Access
Media
Gateway
FE
Access transport
T-3: Edge
Node FE
Access Packet Transport Functions
T-5:
Access
Border
Gateway
FE
T-9:
Signalling
Gateway
FE
T-6:
Interconnection
Border
Gateway FE
T-7:
Trunking
Media
Gateway
FE
Core Packet Transport Functions
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
Scope of NGN
PSTN/ISDN
9
NGN example of service domains
(Appendix I Figure I.5 of Y.2012)
Internet
Services
2
Operator A
3
1
Laptop
IP Connectivity
Access Network
IMS
Services
Core Transport
Network
Internet
Services
Internet
Non-SIP
Services
Operator B
Core Network
Access
Network
1 ： IMS services
2 ： Non SIP service
3 ： Internet service
Core Network
Firewall
Transit
Network
Transit
Network
IMS
Services
Core Transport
Network
Access
Network
IP Connectivity
Access Network
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
10
S/BC: Session Border Controller (Supplement 1 to Y.2012)
S/BC
S/BCallows
allowsreliable
reliableinterworking
interworkingbetween
betweendifferent
differentproviders.
providers.
Signalling path gateways
IBCF
Provider
ProviderAA
IBCF
Provider
ProviderBB
I-BGF
I-BGF
Media level gateways
Examples of functions
1. Support for differentiated QoS
• Packet rate limiting
• Validation of priority setting
• Performance monitoring
2. Protection of the network
• NAT and firewall control
• Topology hiding in signalling
3. Additional service features
• IPv4/v6 translation
• Codec translation
4. Charging and accounting
• Packet number counting
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
11
Scope of NGN Release 1 and corresponding benefits
NGN release 1 scope
• • Re-use
Re-useand
andadaptation
adaptationofof3GPP
3GPPIMS
IMStoto
provide
providemultimedia
multimediaservices
services
• • AAunified
IP
network
with
unified IP network withimproved
improved
security
and
QoS
security and QoS
• • Broadband
Broadbandaccess
accessable
abletotoprovide
provideIPTV
IPTV
• • AAvariety
varietyofofmobile
mobileand
andfixed
fixedterminals
terminalsand
and
their
theirprofile
profilemanagement
managementtargeting
targetingFMC
FMC
• • Media
Mediaprocessing
processingtotoassist
assistcontent
contentdelivery
delivery
• • Service
Servicedelivery
deliveryplatform
platformmaking
makinguse
useofof
NGN
NGNeasily
easily
• • Border
Bordergateways
gatewaysenabling
enablingsecure
secure
interworking
interworking
• • Evolution
Evolutionscenario
scenarioofofPSTN
PSTNand
andshort-term
short-term
solution
solution
Benefits
Cost saving
Versatility
Friendliness
Inheritance
Reduction of installation
and operating costs
Expansion of
service features
Creation of new
business opportunities
Preservation of
existing services
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation Networks"
Dar es Salaam, 3-5 October 2006
12
Overview of NGN Release 1
Service delivery
platform making use of
NGN easily
Applications
Service Stratum
A variety of
mobile and fixed
terminals and
their profile
management
targeting at FMC
Application Support Functions and
Application
Functions
Service Support
Functions
S. User
Profile
Functions
Other NGN Service
Components
Service
Control
Functions
Legacy
Terminals
Legacy
Terminals
Customer
Networks
NGN
Terminals
End-User
Functions
IP Multimedia
Component
IP Multimedia
&PSTN/ISDN
Simulation
Service Component
GW
GW
Network Attachment
Network Access
T. User
User
Control Functions
Profile
Profile Attachment
(NACF)
Functions
Functions
Functions
AccessTransport
Network
Access
Functions
Functions
Edge
Functions
Resource and Admission
Control Functions
(RACF)
Re-use and
adaptation of
3GPP IMS to
provide
multimedia
services
Other Networks
PSTN/ISDN Emulation
Service Component
Evolution
scenario of PSTN
and short-term
solution
A unified IP network
with improved
security and QoS
Core Transport
Core transport
Functions
Functions
Transport Stratum
Border gateways
* Note: Gateway (GW) may Media
exist in either
Transportto
Stratum or End-User
processing
Broadband access
able
Functions.
enabling secure
assist content delivery
to provide IPTV
ITU-T/ITU-D Workshop "Standardization and Development of Next Generation
Networks"
interworking
Dar es Salaam, 3-5 October 2006
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