ramya_wawc

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A Gateway For SIP Event Interworking

-SasuTarkoma

&

Thalainayar Balasubramanian Ramya


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MOTIVATION

Interworking of SIP event framework with the generic

publish/subscribe system

SIP Event Framework does not support anonymous

one-to-many event dissemination

Challenges:

SIP Event Framework does not support expressivefiltering

Proposed Solution:

Implementation of a gateway component enabling

interworking between the SIP event framework, andpublish/subscribe system

Application of the proposed Gateway:

Universal Data Access


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BACKGROUND INFORMATION

Session Initiation Protocol (SIP) : a standard, text-based,

application layer, signaling protocol developed by the

Internet Engineering Task Force (IETF). Described in

RFC 3261

Purpose of SIP:To establish, modify and terminate multimedia

sessions over the IP network

Acceptance as standard: Selected by the 3rd Generation

Partnership Project (3GPP), as the session establishment

protocol for the 3GPP IP Multimedia Core Network Subsystem

(IMS)


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SIP Application Areas:

Internet Telephony

Control Applications

E-Commerce

Multimedia Conferences

Instant Messaging

BACKGROUND INFORMATION


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SUBSCRIBE

NOTIFY

NOTIFY

200

200

200

SIP EVENT FRAMEWORK

SIP Event Framework: An extension of Session Initiation

Protocol, described in RFC 3265

Methods supported: SUBSCRIBE, NOTIFY

Fig 1. SIP Event Subscription and Notification

SUBSCRIBER NOTIFIER


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Forward subscription to notifier proxy

SIP Proxy1(Redirect mode)

DNS

DNS lookup

SIP Proxy2(Redirect mode)

UAC3

Forw

ar d

request

t onot

ifi e

r

Update location server

No t i

fic

atio n

res

p o n

set

o p ro

xy

Forw

ard

SUBSCRIBE

Registrar Location Server

UAC1 UAC2

register

register

Forward

notificationtos

ubscriber

Proxyquery

Forward notification to subscriber proxy

ForwardSUBSCRIBEto

notifier

Fo r w a

rd n

o t i

fic

at i

o n

t o

n

o t i

fie

rp r o

xy

SIP DOMAIN

Fig 2. Working of SIP Domain


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COMPONENTS IN SIP DOMAIN

SIP Proxy: Receives SIP requests/responses from clients/proxies, processes, and forwards it to the next hop

or final destination

SIP Client: Receives/Sends SIP requests/responses

Location Server: Stores updated client information

Redirect Server (Redirect Mode): Provides the contacted

clients current address to the contacting client

Registrar: Maintains registered clients information, queries

and gets recent updates from Location Server


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APPLICATION AREAS OF CONTENT BASED

PUB/SUB EVENT MODEL

Active Badge Systems

Proximity Sensors

Information and Multimedia Delivery Services

Positioning Systems


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P1

P2

Pn

S1

S2

Sn

Subscribe()

Unsubscribe()

Publish()

Publish

Publis

h

Unsubscribe

Subscribe

WORKING OF PUBLISH/SUBSCRIBE EVENT MODEL

Fig 3. Publish/Subscribe Event model

Event ServicePublishers Consumers


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Gateway

SIPDomain

Pub/Sub

Domain

I

O

I

O

Conversion, Mapping,

State

GATEWAY DESIGN

Fig 4. Gateway Design


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NIST-SIP

STACK

JAIN-SIPProxy

SIP clients

Fuego Event

Service

FuegoClients

G

A

T

EW

A

Y

subscribe/

publish

subscribe/

notify

IMPLEMENTATION ARCHITECTURE

Fig 5. Implementation Architecture


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GATEWAY FUNCTIONALITIES

Receive SIP messages (requests/responses)

Convert SIP message to pub/sub messages. Forward the

converted messages to Fuego domain

Receive pub/sub messages

Convert pub/sub messages to SIP messages (requests/

responses). Forward the converted messages to the

SIP domain

Associate the received messages using unique identifiers.Call Identifier of the SIP and subscription identifier of the

Fuego message are used for association.

Generate and send SIP provisional responses to the SIP

domain


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SIP DOMAIN

SUBSCRIBE

Forward SUBSCRIBE

Process

subscription Subscription

status

Forward SIP

response PUBLISH

Forward NOTIFY

OK

Mapping, reformat

SUBSCRIBE

Create SIP

response

Mapping, reformat

PUBLISH

GATEWAY FUEGO SYSTEM

SIP AND FUEGO SUBSCRIPTIONS/NOTIFICATIONS

Fig 6. SIP SUBSCRIBE and Fuego PUBLISH


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Fuego SystemSIP Domain Gateway

SUBSCRIBE

Forward

SUBSCRIBE

NOTIFY

Forward

NOTIFYOK

Process

subscription

Mapping, reformat

NOTIFY

OK

SIP AND FUEGO SUBSCRIPTIONS/NOTIFICATIONS

Fig 7. FUEGO SUBSCRIBE and SIP NOTIFY

Mapping, reformat

SUBSCRIBE


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MOBILITY IN THE INTERWORKING ARCHITECTURE

Interdomain mobility:

Need buffering of messages at the gateway

Roaming clients can send a signal to the gateway informing

their location update, and get the buffered messages

Intradomain mobility:

Intradomain terminal mobility is possible in both the SIP and

Fuego domains

Disconnected operation should be supported for usermobility


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ADVANTAGES OF THE GATEWAY COMPONENT

Performed scalability and performance test for the gateway

Used the presence event package

Advantages:

+ Supports extensibe implementation

Experimentatal observation:

+ Transparent architecture

+ No modifications in the API of the interworked domains


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Conclusion

Future Work:

Enhancing gateway functionality by providing filtering

support, and load balancing

Under heterogenous environments interworking of different

event standards is essential

Investigate the possibilities to provide various mobility support

such as session mobility


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REFERENCES

National Institute of Standards and Technology (NIST)

SIP (Session Initiation Protocol) Stack and Proxy:

http://snad.ncsl.nist.gov/proj/iptel/

Java APIs for Integrated Network (JAIN) Session

Initiation Protocol (SIP) API:

http://www.jcp.org/aboutJava/communityprocess/final/jsr032/


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QUESTIONS ?


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THANK YOU !

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