1999-09-30 EUC'99 1

A SIP-ISDN Gateway

Hans NilssonCSLabEricsson Utvecklings AB

hans@erix.ericsson.se

1999-09-30 EUC'99 2

What is SIP ?

Session Initiation Protocol, RFC 2345Initiating, Changing and Terminating

Multimedia conferences (IP Telephony)

Lightweight

Textbased ”Looks like HTTP”

UDP (TCP)

1999-09-30 EUC'99 3

Future of SIP?

Easy to implement => many small

companies

Mail servers, HTTP Servers, SIP servers hans@cslab.ericsson.se sip:hans@cslab.ericsson.se

Web integration; Services on web pages Click-to-dial

1999-09-30 EUC'99 4

SIP, Simple Example

INVITE

200 OK

ACK

Audio, video, ...

BYE

200 OK

1999-09-30 EUC'99 5

SIP Redirect Server Example

INVITE

200 OK

INVITE

200 OK

••

302 Redirect

REGISTER

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SIP, Other Example

REGISTER

REGISTER

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What is a Gateway?

Audio

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SIP/ISDN Gateway

SignallingGateway

MediaGateway

Controller

MediaGateway

ISDN

SIP

RTPPCM

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SIPstack

SIPstack SIP

stack

SIPstack

SIP - ISDN

ISDNstack

ISDNstack

EncodeDecode

Resending

TCPUDP

Messagesupport

SNMP HTTP

State machineState machine

1999-09-30 EUC'99 10

Erlang code sizesin number of source lines

Encode/decode 1511

SIP stack 2476

State MachineSIP <-> ISDN

2285

ISDN stack 6862

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SwitchBoard

SIP/ISDN Gateway - realisation

IP Network

IPI

100BaseT

RTP4 x E1/T1

ISDN Network

PCI

ISDN DSS1

SIP

10BaseT

IP Network

Distributed Erlang

1999-09-30 EUC'99 12

Why Erlang/OTP?

1999-09-30 EUC'99 13

Hot code upgrade

External interfaces

Components/Libraries: Mnesia SASL SNMP Inets GS ...

Concurrency lightweight processes

Distribution transparent message

passing

Robustness node fail-over process monitoring

Soft real-time

Some characteristics [http://www.erlang.org/white_paper.html]

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Users

1999-09-30 EUC'99 15

Mobility Server VoIP Prototype Configuration

NT Server: Mobility Server

Feature

ISDN SIP H.323

DECT

SWB

PLMNPTN

IPI

RE

H.323

IP

H.323SIP

WirelessLAN

FeatureFeature

PSTNTNI

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• Show Inter-operability between IP Terminals and DECT Terminals or PSTN

• Identify effects from implementing existing Mobility Server services over VoIP

• Create qualified arguments on SIP versus H.323 for the Mobility Server product

Mobility Server VoIP Prototype Objectives

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The Future

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Future:Work, work, work...

Standard MG protocol (MGCP,…)

Less prototypish :-)

Administration: SNMP HTTP/CGI

Connect to Ericsson Phone Network

1999-09-30 EUC'99 19

Redundancy and Capacity

SwitchBoard

IPI PCI

SwitchBoard

IPI PCI

SwitchBoard

IPI PCI

“Eddie”

SIP

“Eddie”

“Eddie”