Post on 01-Feb-2018
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006
International Telecommunication UnionITU-T
IMS based NGN IMS based NGN ArchitectureArchitecture
and its application and its application
Dick KnightBT Group plc
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 2
ITU-TOutline
o IP Multimedia Subsystem• Overview & Key Features• Use in NGN• Benefits
o Support for PSTN/ISDN Replacement• Simulation• Emulation
o Overall Architecture• ITU-T SG13, ETSI TISPAN & BT 21CN
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 3
ITU-TIP Multimedia Subsystem
o SIP-based control system to enable media-agnostic service delivery in IP networks• Secure registration• Secure communications• Location independence• Separation from Service providing application• Specified by 3GPP
o Control system for a flexible service delivery platform
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 4
ITU-T
Key Elements
UE P-CSCF S-CSCF
ASHSS
Transport Network
NACF & RACF
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 5
ITU-T
Key Elements Functionality 1
o UE – User Equipmento P-CSCF
• Proxy Call Session Control Function
• First contact point• Forward SIP messages
from UE to S-CSCF and vice-versa
• Generation of CDRs.• Maintain security
association to UE• Authorisation of
bearer resources
o HSS Home Subscriber Server• Mobility Management• User security• Service Provisioning &
authorisation support• Call / Session
establishment support• GUP Data Repository• Identification handling• Access authorisation• Application Services
Support
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 6
ITU-T
Key Elements Functionality 2
o S-CSCF• Serving Call Session
Control Function• Control for registered
UE sessions• May behave as Proxy
Server or User Agent• Interaction with
Services Platforms• Provide endpoints
with service event related information
• Obtain Address of entry point for network serving the destination user
• Modify the SIP request according to HSS and service control interactions
• Perform preference and capability matching
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 7
ITU-TIMS in NGN
o Performs Service Control Functions• Within the service stratum• Meets the requirements of Y.2001
o Flexible approach to services• Service delivery using Internet applications,
services and protocols
o Provides inherent mobility supporto Already exists!o BUT – specific to IP Connectivity Access
networks
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 8
ITU-T
RACFNACF
IMS Adaptations in NGN
Specific adaptations to NGN – generic access
IMSUE
Transport Network
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 9
ITU-T
IMS Adapted to NGN
o Control of IP Transport Networks (admission control, QoS, authentication, etc.)
o Co-ordination of multiple control components to a single core transport
o Interworking and interoperability with legacy and other networks
o Mutual de-coupling of applications from session/call control and transport
o Access technology independence of session/call control and applications
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 10
ITU-T
Architecture of IMS for NGN
Figure 1 of draft ITU-T Recommendation Y.IFA
MGW
MGCF CSCF
BGCF
CSCF BGCF
SLF
P-CSCF
MRFP
MRCF
Mk
Mi
Mw
Dx
Cx
Mr
Mg
Mw
Mj
PSTN
Mn
Mp
Mm
Mb Gq Gm
Sh
Dh
ISC
HSS
Other IP Multimedia Networks
PSTN
IP Connectivity Access Network
Mb
UE
AS
Mb
Mb
(AAA+DB)
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 11
ITU-T
PSTN/ISDN Replacement
Simulationo Interactions between
AS and UE provide “PSTN/ISDN-like” services to NGN Users
o IP “Terminals”o Includes terminal
adapterso Network and UE based
services
o Example use of IMS
Emulationo PSTN/ISDN service
capabilities and interfaces using adaptation to an IP infrastructure
o Legacy user equipment and interfaces unchanged
o Two approaches:• Call Server
(Softswitch)• IMS-based
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 12
ITU-T
S-CSCF
AS(ISUP-aware)
HSS
AGCFH.248
IMS-Based Emulation
Transport Network
NACF & RACFPSTN ISDN UE
Access Media G/W
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 13
ITU-TAdvantages of IMS PES
o Preserves common interface to RACS & transport network
o Common service control functionso Common Routing and configuration data
between emulated PSTN/ISDN Users and NGN Users
o Economy of scale• Consider effects of reducing numbers of
emulated users• Provision of advanced services
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 14
ITU-T
Service Control Architecture
ANIApplication
Application Support Functions &Service Support Functions(may include own Authentication, Authorization and Accounting)
ANIApplications
Application Support Functions & Service Support Functions(may include own Authentication, Authorization and Accounting)
other IP MMNetwork
(e.g. IMS)
PSTN/ISDN
Internet
Other NGN
Access Packet Transport Functions
NACF
End-User Functions
Core Packet Transport Function
RACFNGN UNI
Subscription
User Authentication
& authorisation
UserSignalling I/W
Media Res. Broker
Media G/WControl
Subscription
User
SubscriptionLocator
User Profile Network Sig.Interworking
MultimediaService FE
I/C BorderG/W Control
I-CSCF
S-CSCF Breakout
G/W Control
Media ResourceControl
P-CSCF
AccessGatewayFunction
Based on Y.FRA Fig. 3
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 15
ITU-T
ETSI TISPAN Architecture(* apart from IMS-based PSTN Emulation)
Other IP N
etworks
IP Transport (Access and Core)I-BGF
UPSF
P-CSCF
I/S-CSCF
BGCF
SLF
ChargingFunctions
IWF
PSTN Emulation (R2)
Mw
Mw/Mk/Mm
MrMg
Mj
Mi
Mp Mn
GmGq'
ISCCx Dx
DhSh
Ic
Rf/Ro
Rf/Ro
IbIw
Gq'
PSTN/ISD
N
SGFMRFC MGCF
MRFP
e4
Ie
MwIBCF
MkMk
Application ServersRf/Ro
AGCF
e2
P1
P2
P3
UE
CNG
MG
IMS /PSTN Simulation
Gq'
SPDF
A-RACF
Resource & AdmissionControl
RACS
SPDFNetwork
AttachmentSubsystem
Re Ia
RCEF BGF
UtUt
T-MGF
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006 16
ITU-T
BT 21CN Architecture
H248
POTs
OSA ASCall Application
Servers
SIP Application Server
AS AS AS
SIP Stack
SIP Application Servers
OSA AS
AE
OSA SCS
MRFC MGCF
HSSplus ISC
Mr
Mp
Mg
Mn
P- CSCF
I-CSCF
Gq’Gm
Mw
Sh
S-CSCFMw
SCIMISC
Ia
IMS
RqSPDF
ReSGF
Cx
BCF
SPDFMw
P2
Presence
Messaging
Other TDMNetworks
3rd PartyApplications& Services
Other IPNetworks
ExternalApplication
s
IAD
MediaServer
MPLS/IPNetwork
MediaGateway
BorderGatewayWiMax/WLAN
PSTN
BRASBorder
GatewayBackhaul
MSAN
OtherIMS
C7
SBR(ENUM)
PSTNCall ServerCAC
BWM
A-RACF
Metro and CoreMSAN and Access
Service Assembly
AGCF
SIP
e4e2
e1
ITU-T Workshop “NGN and its Transport Networks“Kobe, 20-21 April 2006
International Telecommunication UnionITU-T
Thank YouThank You