IMS Based PSTN/ISDN Emulation

IMS based PSTN/ISDN EmulationAchievements & Experiences

Dan CHEN, Ph.D.

IMS chief engineer

Email: [email protected]

© ZTE Corporation. All rights reserved.

Why IMS based PSTN/ISDN emulation?What is IMS based PSTN/ISDN emulation?


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


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


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


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


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


Experiences & Case Studies


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


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


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


ISDN/PSTN User Profile Migration Tool

CSCFAGCF

MSAN

User Data

HSS

MGCF

MMTEL AS

Exported Files

fr om PSTN

MGW


Flexible Provisioning Solution

MMTEL AS ENUM/DNSHSS

BSS

AGCF

Service Provisioning Node


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

IMS Based PSTN/ISDN Emulation

Documents

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