Creation and Operation of Hybrid Services

1Hybrid services [email protected] http://icawww.epfl.ch

Creation and Operation of Hybrid Services

Jean-Pierre HubauxInstitute for computer Communications and Applications (ICA)

Swiss Federal Institute of Technology, Lausanne (EPFL)

Currently on leave at UC Berkeley, EECS Department

Note: This work was initiated at the IBM T.J. Watson Research Division, Hawthorne, NY, in Spring 1998

Other contributors:

Giovanni Pacifici, Asser Tantawi (IBM Research)

Constant Gbaguidi, Maher Hamdi (EPFL/ICA)

2Hybrid services Jean-Pierre Hubaux

Example of Hybrid Network: GSM, PSTN and Internet

BS MSC

PSTN

Gateway Internet

Air interface:- circuit (GSM)- packet (IMT-2000)

MS

MS: Mobile StationBS: Base StationMSC: Mobile Services Switching Center

WebServer


Problem Statement

• Definitions– Hybrid network: internetworking of both the Internet and the telecom

network (including the cellular network)

– Teleinformation Service: set of features, provided end-to-end by a service provider with a commitment in terms of QoS:Teleinf. Service = Contract/QoS + Distributed Application + Connectivity

– Hybrid service: teleinformation service running on a hybrid network Note: by “Internet” we intend the broad family of IP-based networks, including the Intranets

• Problem: how do we define, create, operate and manage hybrid services?


Old Telecom Beliefs related to Network and Service Architectures

• B1: “The services will continue to be primarily provided by the network rather than by the terminals” ==> evolution of the IN: CS-1, CS-2,...

• B2: “The TMN is the solution for network management”

• B3: “Protocols and services are such complex systems that they require to be fully specified before being developed”

• B4: “The B-ISDN will be based on end-to-end ATM”

• B5: “In order to cope with the complexity and diversity of the new services, with the need to integrated network and service management and with deregulation, a distributed, object-oriented platform is required” ==> TINA


B1: “The services will continue to be primarily provided by the network rather than by the terminals”

Probably true for voice-oriented mobility services

CS-1 CS-2 CS-3

UPT-1 UPT-2

GSM-1 GSM-2

CT2DECT

CT2+DECT+

UMTS (ETSI)IMT-2000 (ITU)

CT : Cordless TelephonyDECT : Digital Equipment for Cordless TelephonyUPT : Universal Personal TelecommunicationUMTS : Universal Mobile Telephony SystemIMT-2000 : International Mobile Telecommunications 2000

Functionality of the IN:- location information, registration and retrieval- call routing- authentication- charging- handover


Example of Hybrid IN-based Service: the WebIN/NEXUS Project of HP Labs (1/2)

(Adapted from Colin Low: “Integrating Communication Services”, IEEE Comm. Mag., June 1997)

SSP SSP

SCF SCF

Service switching function

Service control function

SCF/SMFInternet

Servicedata/controlfunction


Example of Hybrid IN-based Service: the WebIN/NEXUS Project of HP Labs (2/2)

Serviceswitching

point

Servicecontrol

function

PSTNIncoming call

Redirected call

INAP

Serviceprovider

Web server

SubscriberWeb server

EnterpriseWeb server

HTTP GET: Incoming call

Redirection Number

Implementing call redirection:


B2: “The TMN is the solution for network management”

• True or false, but most probably false– The driving idea behind the TMN is that network management is such a

complex task that it necessitates a complex solution

– However, the TMN protocols are OSI-minded and have the OSI drawbacks

– Large (data) networks are managed with simpler solutions (SNMP)


B3: “Protocols and services are such complex systems that they require being fully specified before being implemented”

• False– Committee work based on consensus has led to the high complexity of

ITU and ISO proposals

– The Internet development has proved that it is possible to do first and standardize later; incremental development

– Hence, some traditional ideas of software engineering such as the waterfall model are questionable when applied to protocol development

– Speed to the market is now a key factor for the success of a new technology


B4: “The B-ISDN will be based on end-to-end ATM”

• False– The integrated services network will be the Internet, enriched by:

• resource reservation mechanisms

• additional mobility mechanisms

• appropriate billing mechanisms

• additional security mechanisms– ATM will be confined to the backbone

– In the end-system, ATM may still have a chance for some mission-critical applications (telemedicine, defense,...)


B5: “In order to cope with the complexity and diversity of the new services, with the need to integrated network and service management and with

deregulation, a distributed, object-oriented platform is required” ==> TINA

• Strengths of TINA– Backed by many network operators

and computer manufacturers

– Strong connection with the OMG (OMG TELSIG)

– Proposes an elegant solution to network and service management in a deregulated market

• Weaknesses of TINA– Lack of clear added value to either network

provider or equipment supplier

– Concerns about the maturity of base technology (CORBA performance: ?)

– Many services have already been provided over the Internet without a specific service architecture


Architectural Separation of TINA

Information network (based on CORBA)

Transport network (ATM)

X X

X

Information Network = kernel Transport Network (kTN) + set of applications


A Possible Integration

IIOP: Internet Inter-Orb Protocol

Information network (CORBA)

Best-effort-services

R

R

R


Best-effort services

R

R

R

IIOP IIOP To the ORBsof otherstakeholders

Network operator 1 Network operator 2Billing,Management,VPNs,other sophisticatedservices

Services with reservations

XX X

X

Services with reservations

XX X

X

TransportNetwork


If CORBA proves to be Successful...


Best-effort servicesR

RR


RR

R

IIOP

Consumer

High-speedNetworkInterface

IDL

Retailer

IDLThird Party

Service ProviderIDL

High-speedNetworkInterface

Operatedby the Telcos

Services with reservations Services with reservations

(maybe a simpler,Web-based

interface would be enough here)

Best-effort services


Conclusion on TINA

• The things the TINA-C did right:– explore the concept of service in all its generality

– base the architecture on an object oriented middleware (CORBA)

– try to integrate service provisioning and service management

• The things the TINA-C did wrong:– consider for too long that ATM was the end to end support of the B-ISDN

– ignore for too long the Internet

– remain for too long a closed community of incumbent telcos

– not have a clear migration path from existing networks to the envisioned architecture


Conclusion on Telecommunication Architectures

• The proved capacity of the Internet to run multimedia services (including telephony...) dramatically changes the landscape for the Telcos

• The IN should survive, especially for the provision of voice services related to terminal mobility

• Network management requires further investigations and probably new paradigms

• Some fundamental TINA principles need to be revised

• A possible way to cope with the contradictory expectations (flexibility at the level of the Internet and availability at the level of the telecommunication services) is to split the WAN resources into 2 parts:– One devoted to best-effort services

– The other one devoted to services with reservations

• These resources would be controlled by the Information Network


The Integrated Services Digital Terminalis Wireless

• In 2-3 years, a smart phone could feature:– CPU: 200MHz

– RAM: 16 MB

– Hard disk: 1 GB

– Bandwidth: up to 1 or 2 Mb/s (IMT-2000, UMTS)

– Small screen: typically 600x200 pixels

– Keyboard and/or handwriting recognition and/or voice recognition (monospeaker is enough); voice recognition is local or on a server

• Such a smart phone could be the “mobile office” of the nomadic worker.

• Ideally, it should be able to roam in-building (WLAN, DECT), in small cells (DECT, GSM or CDMA), in large cells (GSM or CDMA) and in remote areas (satellite)


Assumptions for our Migration Scenario

• 1. The telecom (PSTN and cellular) and Internet networks will coexist for many years (hybrid network)

• 2. Hybrid services make sense and have a potential market

• 3. Mobile terminals will foster the development of hybrid services (“Integrated Services Digital Terminal”)

• 4. Speech synthesis and speech recognition will also fuel this development


Service Creation in the Hybrid NetworkServiceCreation

Environment

Internet

PSTN(and N-ISDN)

CellularNetwork

API

API: Application Programming Interface

Java Service Layer (built up by assembling beans)


Service Creation (cont’d)

Service Creation Environment Service Factory

Service Instance

Beans Archive

1. Identify a sufficient set of Beans

2. Identify service components used by the Beans and map them onto physical resources

SC SCSC

Middleware

CT/S3

CT/S1

Middleware

CN/S3

CN/S1

Middleware

CC/S3

CC/S1

Middleware

CG/S3

CG/S1

Controller Controller Controller Controller

Terminal Network Node Control Server Gateway

Java Service Layer

CT/Si: Component on Terminal for Service #iCN/Si: Component on Network node for Service #iCC/Si: Component on Control server for Service #i

CG/Si: Component on Gateway for Service #iSC: Service Component

3. Build the middleware


Why Java?

• Pros:– Platform neutrality: increased portability

– Object-orientation: increased re-usability

– Simplicity: better garbage collection, no pointer manipulation nightmare

– Multi-threading: a few lines for creating threads

– Distribution: possibility for Java applets to interact with their home site

– Dynamicity: use of servlets (“applets” executed in Web servers)

– Security: still more secure than most widely used languages

– Extensibility: sharing of Java packages among developers

• Cons:– Performance: lesser than with other languages such as C or C++


Service Modeling: A Way to Identify Components

A Service is composed of features, each of which is associated with an object model. Classes in the models are the sought components

Customer Service

Feature

defines *

Charging Call control Connectivity User Interaction

involvesinteracts with

Permission

User

sets

Address Translation

Security

Inheritance

Composition

Object class

Association class

Key:


Example: Address Translation

• End-system is a generic concept that embraces terminals, gateways, information converters, multipoint control units, etc.

• The user makes use of a device (e.g., a Smart Card) that has an address

• The user may have a higher level address (e.g., email address)

• The user can bind addresses with one another

Device Device Address

User Address Binding

has1 1

1

manages

uses1

*

End-system

*

*User Address

Device Address

Address

User Address

1

1

End-system

Terminal Gateway Info Converter

has

Inheritance

Composition

Object class

Association class

Key:


Example: IP Telephony with H.323 from ITU-T

Internet PSTNH.323H.323

IP Ph. Gateway

H.323

IP Ph.

IP Phone 1

IP Phone 2

• Foundation for audio, video, and data communication over IP• Point-to-Point and conferencing • Products from VocalTec, Microsoft,…• Key technology for “New Telcos”


Provision of Hybrid Services (Call Center, VPN,…) in a PSTN-Internet (H.323) Interworking

PSTN IP NetworkGateway

Jar of beans

Downloadableapplication

ServiceCreation Environment


Call Forwarding in a PSTN - H.323 Scenario

SSP SSP

SCP

H.323GW IP Network

H.323GK

Java Service Layer

SCP: Service Control Point GK: GatekeeperSSP: Service Switching Point GW: Gateway

IntelligentNetwork


Trigger-Event-Source and Trigger-Event-Listener model

Network element

Java Service Layer

Trigger-Event-Source

Trigger-Event-Listener(implements methods to handle the events caught)


Generic Information Flow

Event Source

fires TriggerEvent

goes to TriggerEventListener

fires CnxAttemptEvent

CnxFailEventfires

fires

goes toConnectionBindingConnectionFactory

goes to

Connection

createsCnxCompleteEvent

goes to creates

: Service component : Event


Closed User Group in a PSTN - H.323 Scenario

GW: GatewaySCP: Service Control PointSSP: Service Switching PointBSS: Base Station SystemMSC: Mobile Switching CenterCUGS: Closed User Group ServerGi: member of CUGi

SSP SSP

SCP

H.323GW IP Network

CUGS

Java Service Layer

IntelligentNetwork

MSCBSS

G1 G1 G1 G1G1G2G2G2

Functions provided by the Closed User Group Server:- Group management: create/delete group, add/remove user,…- Authentication and access control: according to the characteristics of each terminal, activate the appropriate procedures- Paging: retrieve where an end-user, member of the CUG, is located; based on this information, activate the appropriate terminal


Conclusion

• Teleinformation services, and in particular hybrid services, are going to play a major role for residential and business users

• Too little attention is devoted to the huge legacy of the telecommunication networks: these networks will continue to expand

• The telecommunication architectures need to be substantially revised in order to integrate the flexibility of IP networks

• In the presented proposal, services are being implemented in the different elements of the network: terminal, node, information server, control server, gateways

• By opening key elements of the network (notably SCPs and gateways), it is possible to provide a wealth of hybrid services

• Unlike TINA, this approach leverages on existing networks and mechanisms to gracefully introduce new services


References

For more information, see C. Gbaguidi, JP Hubaux, G. Pacifici, A. Tantawi:“An Architecture for the Integration of Internet and Telecommunication Services”,Technical Report TR 98/025, downloadable from http://sscwww.epfl.ch

On the same Web site, see also “The Impact of the Internet on Telecommunication Architectures”, JP Hubaux et al., Computer Networks and ISDN Systems, Special Issue on Internet Telephony, December 1998, Technical Report TR 98/001


CFP IEEE Communication Magazine

Feature Topic Issue on The Provision of Communication Servicesover Hybrid Networks

Publication: July 1999Submission Deadline: January 5, 1999

Guest Editors:

Jean-Pierre Hubaux David NagelSwiss Fed. Inst. of Technology, Lausanne President, AT&T Labs

http://www.comsoc.org/~ci

Creation and Operation of Hybrid Services

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