IMS based PSTN/ISDN EmulationAchievements & Experiences
Dan CHEN, Ph.D.
IMS chief engineer
Email: [email protected]
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Why IMS based PSTN/ISDN emulation?What is IMS based PSTN/ISDN emulation?
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Why IMS based PSTN/ISDN Emulation
C. Maintenance Resources -66%*
D. Footprint -37%*
B. O&M - 53%*
A. Power Consumption - 34%*
Avoid high maintenance fee of legacy switches
Save the cost of “first adopting Softswitch and migrating to IMS later”
Introduce centralized core as the unique control and service triggering platform for both fixed and mobile networks
Add new value-added services for legacy users, such as one number and converged Centrex
* Source: one of ZTE IMS based PSTN Emulation Projects
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Architecture of IMS-based PSTN/ISDN Emulation
All users (broadband access and narrow band access) are controlled by an unified IMS core network.
MMTEL AS serves for both 3GPP SIP users and H.248/ISDN(BRI/ PRI),V5,H.323, NCS, MGCP, normal SIP users.
Core Layer
MGCF
Service Layer
P-CSCF
IN
HSS
Access Layer
LAN/xDSL/
xPON
PRI
V5UA/IUA
SIP
IP PBX
Other Network
PBX
SIPH.248
H.248/SIP
TG
LSLS
TS
PSTN
IM-MGW
MMTEL AS
(PSS/PES)
I/S-CSCF
BOSS
EMS
SBC
NCS/H.323/MGC
P Terminal
SBC
ONUONU
V5/V5ISDN
AGCFH.248
AG
H.248/M3UA
SIP AS
IM-SSF
ISUP
POTS
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PSTN Class 5 Emulation Solution
LS
LAN/xDSL/
xPON
PSTN
PRI/V5/ISDN
H.248
I/S-CSCF
AGCF P-CSCF
HSS
SIP
MSAN
H.248
• Swap aged PSTN Switches with MSAN, which connects with IMS core via AGCF/P-CSCF.
• PRI/V5/ISDN users remain unchanged and access IMS via AGCF/MSAN.
V5UA/IUA
H.248/SIP
SBC
ONU
MSAN
LS
LSLS
MSANMSANMSAN
ONUONU
MMTEL AS
H.248
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Two Approaches for PSTN/ISDN Emulation
AGCF + MSAN
• AGCF is the service control point for all
the AG users
• AGCF could support multiple types
interfaces beyond standards
SIP MSAN + P-CSCF
• Each SIP AG is the service control point
for its users
• SIP AG only supports SIP
IMS Core
I/S-CSCF
HSSMMTEL AS
AGCF
H248 AG
VGW
(SIP AG)
POTS
IP Network
SIPSIP
POTS
H.248/IUA/V5UA/H323SIPP-CSCF
ISDN PBXISDN phonePBX
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Business Trunking Solution
I/S-CSCF
MGCF AGCF P-CSCF
HSS
IM-MGW
PRIPRI/ISUP
SIP
IP PBX
TDM PBX
AG/IAD
H.248
TRK
SIPSBC
• Trunk Model
• PBX connected to MGCF via
IM-MGW by trunk to
interwork with IMS
• Subscriber Line model
• PBX connected to AGCF
through TG/SG/AG if the
uplink interface is PRITG/SG
TDM PBXTDM PBX
• PBX connected to AGCF/P-CSCF
via AG/IAD if the uplink interface
is TRK
• PBX connected to IMS through P-
CSCF through SIP GW
PRI
PBX
SIP GW
SIP
MMTEL AS
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Experiences & Case Studies
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China Telecom( Fujian)
Background
Solution Highlights
Swapping Fujitsu FETEX 150 switch in
Aug, 2010
Establishing an unified core network for
both narrow-band and broadband user.
Advanced ETCA platform for all elements
evolved :CSCF,PSS,AGCF,HSS
Seamlessly cutover to maintain substantial
service experience of PSTN user.
Multi domain features
Customization ability and fast response help
operator keep higher competition in the
marketFuzhou
IMS Core
MGCF
AGCFP-CSCF
LAN/xDSL/
xPON
Province
Center
SBC
SS
NGN
HSS
PSTN
AG/EPON
TG/SG
AG/EPON
ONUONU
MSAN
AG
ONUONU
MSAN
SHLR
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Multi Domain Features in China Telecom
Fu Zhou
MMTEL AS
CSCF
HSS
CG
EMS
Fu Zhou
AGCF
SBCMGW
Ning De
SBCMGW
Nan Ping
SBCMGW
CS CS CS
BOSSBOSSBOSS
MGCF
Partial resource managed byOperator A in City A
Partial resource managed byOperator B in City B
AG AG AG
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S-CSCF
IMS
HSS
On-net call: one IMS user calls a CDMA user
iVPNplatform
PNP:1001 DN:5287001
MGCFMSCe
IM-SSF
AGCF
CDMA
PNP:1002 DN:189xxxxxxxx
Legacy IN Services Experiences – iVPN
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ISDN/PSTN User Profile Migration Tool
CSCFAGCF
MSAN
User Data
HSS
MGCF
MMTEL AS
Exported Files
fr om PSTN
MGW
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Flexible Provisioning Solution
MMTEL AS ENUM/DNSHSS
BSS
AGCF
Service Provisioning Node
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Lower TCO
•Leverage legacy services
•Quick and flexible
multimedia service delivery
capability
•Adding new value-added
services for legacy users,
such as one number,
converged Centrex, etc
•Realize unified OMM, User DB, service handling & charging to simplify operation & maintenance•Break multi-network coexistence with uniform session control & service trigger•Unified platform with easy function switch and consolidation•Reuse existing equipment to the maximum
• Saving the cost & complexity of “first adopting Softswitchand then migrating to IMS later”
• Realize convergence of fixed and mobile, broadband and narrowband, provide full-service operation and enhance operators’ competitiveness
• High density AGCF with multiple access mode capability
• Backward compatibility with non-IMS terminal/device in PSTN
Highlights of IMS-based PSTN Emulation
New
Services
Seamless
& Smooth
migration
Convergent
network