SIP: Bridging the Chasm Between Legacy and Next-Generation Networks

Peter KuciakUbiquity Software

peterk@ubiquity.net

Internet TelephonyMiami, Feb 5-7th, 2003

About Ubiquity

• Ubiquity Software is a telecommunication software development company

• We offer a platform that greatly simplifies the creation process for telecom application developers

• Deploy an architecture that separates applications from network resources

• Define and deliver applications that are truly business-oriented

• Private global company, 100 people, well funded• Products deployed and in trials in over 20 carriers

worldwide

This Presentation

• What you will see– Evolution discussion of the old and the new network models– Approach of bridging them to create the best of both worlds– Many examples of applications and services that bridge

legacy and NGN networks thus creating exciting services

• What you will NOT see– Tutorial on SIP or SS7 or any other protocol– Ramblings about specific technical details– Self promotion

Market comparison – SS7 & VoP

• SS7– In 2000 almost $10 billion shipped– Down from over $12 billion in 1998

• Voice over Packet– In 2000 under $1 billion shipped– Predicting $1.6 billion by 2005

• SS7 still very much dominant – with growth especially in Asia + Latin America

• Wireless not based on VoP – 3G promises all IP• NGN needs bridges to legacy world – can not ignore and

assume green field scenario

Architectual Evolution

Existing NetworkNext-Gen Services

Existing NetworkExisting Services

Next-Gen NetworkNext-Gen Services

Next-Gen NetworkExisting Services

Network Evolution ?

Ser

vice

Evo

luti

on

?

ParallelDevelopment

Why the Evolution to IP?

• Why would one want to consider IP ?

– Offload traffic to IP = save money• New services in SS7 (caller ID, wireless roaming, SMS)

= incredible growth. Over 360 billion SMS messages in 2002 !!! And SMS is only breaking into North America.

– Tunnel SS7 over IP = save money• SP leasing SS7 circuits can pay up to $10/mile on

international coverage. Jumping to IP virtually eliminates this cost + SP’s save money on STP ports!!!.

– Introduce new services = make money• SP creates a new converged service and offers it to

customers. MMS, Click-to-dial, Dial-a-taxi, SMS for parking all generate new revenue from users.

Distributed Services Model

service

switch switch

service

switch switch

service

switch switch

UNI NNI NNI UNI

• Vertically Integrated• Central Control• Switching

ITU

Source: Henry Sinnreich, WorldCom

• Service creation closely tied with capability of the “switch”• Switch specific syntax & environment• Creating new services a “challenge”

Before SIP …

Distributed Services Model

Router Router

RouterRouter

Router

Elected Server Server

• Distributed Control• Simple Architecture• Routing

IETF

Source: Henry Sinnreich, WorldCom

• Open environment• End-to-end service creation• Standards based components

SIP and friends…

Why SIP ?

• The IP model is a technological, economic and cultural phenomenon

• Born of the Internet - the IP world has thrown its weight behind it– IETF– 3GPP

• Promise of much-needed value for tired voice services

• Converged services at last!

THEISV

COMMUNITYTransport Layer

Application Layer

Session Layer

SIP session layer

PresencePresence

Instant MessagingInstant Messaging

PPersonalizationersonalization

Session ChargingSession Charging

User-Friendly AddressingUser-Friendly Addressing

Always-OnAlways-On

Person MobilityPerson MobilityApplication Application ChargingCharging

Terminal MobilityTerminal Mobility

Session MobilitySession Mobility

Switching & Routing

Important Trends …

• Web model has taught us that services can be created at the edge– Encourages rapid introduction and global availability of new applications– Offers immediate, global availability

• The Applications Server and Web Services markets are exploding– Huge ISV community is developing on J2EE and .NET– Telecom services should follow the same models

• The PSTN, mobile networks and Web seem destined to meet– Converged applications will offer compelling benefits– But many protocols must now learn to live in harmony

• Standardization by consensus encourages rapid adoption of new technologies– W3C & IETF vs ITU

• Session Initiation Protocol is gaining momentum– Powerful protocol is accepted in the industry

User-centric not device-centric

But there are still issues …

Single protocol “panaceas” have not deliveredNew technology cannot be deployed without

business case justificationMonolithic solutions have led to vendor lock-in

for application developmentToday’s open development environments are

typically data-centricService providers are struggling to accelerate the

introduction of real applications to boost profitability and increase ARPU

Value of Services …

$8

$2

$7

$19

$4

$20

$1

Basic voice

Rich voice

Location

Multi Media Messaging

Internet access

Intranet Extranet

Infotainment ARPU Total = $61per subscriberfrom about $20!

Source: UMTS Forum

SIP and Friends (IP Gang)

• PINT– PSTN/Internet Interworking Service - extensions to SIP and SDP for IP Access to

Telephone Call Services (RFC2848)• SPIRITS

– Service in the PSTN/IN Requesting InTernet Service (RFC3298)• SIGTRAN

– SIGnaling TRANsport - transport of packet-based PSTN signaling over IP networks (RFC2719)

• MEGACO– Protocol used between elements of a physically decomposed multimedia gateway

(RFC3015)• ENUM

– Use of the Domain Name System (DNS) for storage of E.164 numbers (RFC2916) • WTA

– WAP Telephony Applications• TRIP

– Protocol used for routing telephone calls inside an IP network and for locating gateways

• SIP-TSI– LOOK AT SIPCENTRE DEFINITIONS !!!

SIP Service Capabilities

• Services oriented around the customer not around a device

• Inherent capabilities:– Multimedia sessions (not just voice!)– Instant Messaging– Presence (status of users and events)– 3PCC

• Easily programmable• Integrates with web applications

Where should services reside?

PSTN?Point of

Interconnect?IP Network?

IP(SIP/H323)

PSTN

SS7Softswitch

Analogue Phone

Gateway

IP Phone

Softphone

Hybrid world – just telephony!

IP

DNS Server

User Profile

Database

SIP Phone

SIP Soft User Agent

Analogue Phone

SIP -Enabled Router

IP(H.323)

PSTN

SS7Softswitch

Analogue Phone

Gateway

IPSIP

PhoneFirewall

Firewall

DHCP

SIP Server

IP network architecture

IP

User Profile

Database

SIP Phone

SIP Soft User Agent

Analogue Phone

SIP -Enabled Router PSTN

SS7Softswitch

Analogue Phone

GatewaySIP Server

Application Services Broker

Service Creation Environment

IN Service Creation

Environment

Link at what level?

Link for what reason?

Hybrid world apps and media?

Service creation and delivery

• A myriad of possibilities: CPL, JAIN, “open” APIs, SOAP, CGI, Servlets

• Challenges:– Cross platform implementation of APIs– How “open” is open – just another way to say proprietary?– Where is the service code – integrated , distributed?– What classes of users exist for Service Creation?

• Administrators, Subscribers, operators …– How is the service actually “created”?

• GUI, Proprietary all-in-one, Legacy Integration?

Programming SIP

• Service provider revenues will come from intelligently tying together a number of different features to create targeted, differentiated services

• A multiplicity of possibilities• SIP is the thread that ties together voice, web, email, video, text

• SIP is a textual language based on the request-response paradigm• Its similarity to HTTP will make it a familiar language for web

programmers• Utilise the body of web programmers out there• The call is not the central feature of the application any longer

• There are a number of different APIs with differing characteristics

Call Processing Language (CPL)

• End-user service creation – An XML-based scripting language for describing call services

• Primitives for making decisions and taking actions based on call properties (e.g. caller, time)

• CPL can be uploaded to the network, then instantly verified and instantiated

• Limited scope means server’s security won’t get compromised

• Portability allows users to move CPL scripts across servers

• Scripts may be manually written, generated using GUI tools, 3rd parties….

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE cpl SYSTEM "cpl.dtd"><cpl> <location url="sip:jones@pc.ex.com"> <proxy timeout="8s"> <busy> <location url="sip:jones@vmail.ex.com”> <proxy /> </location> </busy> <noanswer> <location url="sip:jones@vmail.ex.com”> <proxy /> </noanswer> </proxy> </location></cpl>

SIP CGI

• The Common Gateway Interface (CGI) has served as a popular means of programming web services

• CGI scripts have been the initial mechanism to make websites interact with databases and other applications

• Like HTTP CGI, a SIP CGI script resides in the server and passes message parameters through environment variables to a separate process. The process sends instructions back to the server through its standard output file descriptor. SIP CGI is almost identical to HTTP CGI and is particularly suitable for services that contain substantial web components

• A CGI script can be written in Perl, Tcl, C, C++ or Java making it accessible to a large community of developers

• Unlike Web-CGI, SIP-CGI supports proxying and processes responses as well

Servlets …

• An HTTP servlet is a Java application that runs in a Web server or application server and provides server-side processing, typically to access a database or perform e-commerce processing

• It is a Java-based replacement for CGI scripts, Active Server Pages (ASPs) and proprietary plug-ins written in C and C++

• Similar to the CGI concept but, instead of using a separate process, messages are passed to a class that runs within a JVM (Java Virtual Machine) inside the server

… Servlets cont’d

• SIP Servlets are very similar to HTTP Servlets; they simply enhance the interface to support SIP functions

• Servlets are portable between servers and operating systems

• Compromise between security and power: still a powerful generic language but security provided by Java “sand-box”

• A well-defined API is needed. As APIs are not IETF’s business this work moved to JAIN

• http://java.sun.com/products/jain/index.html

JAIN

• JAIN (organised by Sun in 1998) is being specified as a community extension to the Java platform

• It provides a new level of abstraction and associated Java interfaces for service creation across PSTN, packet and wireless networks

• Objective is to create an open value chain– Service portability– Network convergence– Secure network access (JAIN

Parlay)

Service Layer

JAIN Protocol Layer

(IN/AN) (SIP)

Network Layer

(Wireline)(Packet Based)

JAIN Application Layer

(Call Model)

Parlay

• Parlay is complementary with the JAIN umbrella activities• The target market for these APIs are carriers and

independent software vendors• Initial efforts focused on call control, messaging and

security • The Parlay API passes on IN functionality to third parties

while hiding the complexity of the underlying signalling– Java provides an ideal mechanism to make Parlay services

available

– Parlay can expand the reach of the JAIN community by providing security elements

Service capabilities

• Location-based services• Presence triggered services• Enhanced web services• Profile-based services• Entertainment• Information Services• Financial Services• Conferencing

Defining The Role Of An Applications Server

• The communications Applications Server must directly address the needs and requirements of the target trusted ISV community

• The development platform must be standards-based and provide abstracted connectivity to a multitude of commonly used network resources, signaling systems and information systems

– hiding the complexities of direct interaction with discrete network resources and signaling mechanisms

• The solution must provide mediated user-level service interaction, not simply device-level interaction (as with existing Web Apps Servers)

• And should provide common, re-useable, interfaces to those networks resources along with managing the interaction between distinct resources

• Applications Server must allow deployment of developed applications and services in a Carrier environment with expected Carrier grade parameters.

GOAL:To harness the extensive experience, knowledge and energy of the Web

Development Community to enable Carrier customers to bring new, compelling communication applications to market quickly & cheaply

Example: Stock notification service

• Subscribe to movements of stock

SUBSCRIBE

USCL $21.85Stockbroker

NOTIFY

• Click-to-dial stockbroker

• Stock reaches threshold

• Notification sent to UA

Example: Utilising Web Services

SIP Network

Application Server

PSTN

Translation Server

SMS Gateway

• Send an instant message

• Forward message to a translation server e.g. Altavista’s Babelfish

• Translated message returned and forwarded to an SMS gateway

• Message delivered to mobile phone!

Bonjour, tout le monde!

Hello, everybody!

• All existing web services with SOAP interfaces!

• Take it one step further and generate voice file and play to the user instead

of sending text

Desktop UA

SIP enabledMobile Device

Phone

Media GatewayMedia Gateway

SIP

:pku

ciak

@ub

iqui

ty.n

et

Location Server

SIP

:pk

uci

ak@

ub

iqu

ity.

net

192.198.40.2

SIP:pkuciak@ubiquity.net

TelUrl:5691

Contact List

ringring

ringring

ringring

192.198.40.2

SIP: pkuciak@ubiquity.net

TelUrl:5691

Example: User Mobility / Call Centre

REGISTEREDUSER SIP: pkuciak@ubiquity.netCONTACT: TelUrl:5691

REGISTEREDUSER SIP: pkuciak@ubiquity.netCONTACT: SIP:pkuciak@ubiquity.net

REGISTEREDUSER SIP: pkuciak@ubiquity.netCONTACT: 192.198.40.2

Voicemail Server

IP Network(fixed/mobile)

Example: User profiling

• Services Associated With a User Not a Device– User may have Multiple Associations

• Presence Management for Single ‘Number’ Reachability• Selective Call Forwarding Based on Profile

– E.g. Unknown Caller Transferred to Voicemail

Wife

Unknown caller

REGISTER

REGISTER

PROFILE

CALL OK

CALL OKSEND TO VM

Boss

Bert

Romeo

SendSend

Text Message = mobileVoice Message = phoneMail = PC

Friends budy listFriends budy list

Fred…. BusyBert……. Free (Fix)Harry……. Free (Mob)Romeo…… Free (PC)

Notify

Notify

Notify

Notify

Example: Enhanced Presence

SUBSCRIBEEVENT: After 6pm Presence Friends List

TIMETIME6pm – 11pm

SUBSCRIBEEVENT: After 6pm Presence Friends List

SUBSCRIBEEVENT: After 6pm Presence Friends List

SUBSCRIBEEVENT: After 6pm Presence Friends List

PresenceServer

Harry

Fred

Conclusions

• Open, distributed architectures foster innovation• Architectures that bridge legacy and NGN will

allow for greatest range of convergent apps• Abstracted services layer opens up network to

third party developers• Subscribers are not restricted to services offered

by their operators• Convergence of business models in an Internet-

style value chain