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Introduction to (Local Exchange)Softswitch

Bob Ehlers

Director, Business Development

April 26, 2004



> Definition> Overview

> Class 5 vs Local Exchange

>

Why Softswitch> Elements of Softswitch

> Media Server

>

Feature Server> Media Gateway Controller

> Summary



What is a Softswitch?

>

First - Softswitch is an ambiguous term> Softswitch can refer to only the media gateway controller. This

is the device that handles all of the call control. This definitiondoes not include the media services, application services or

media gateway functions.

> Softswitch can also refer to the entire set of functions includedin the media gateway controller, media server, applicationserver and even media gateway.

> We’ll use the entire set of functions



Basic Softswitch Elements

MediaGateway

CallControl

Services

Traditional

ProprietarySingle Platform

Next Generation

Next-Generation

Modular, Open Platform

Services Services

Softswitch

Media

Gateway

RAS IAD



Media

Gateway

Signaling

Gateway

Softswitch Architecture

MediaGateway

Controller

(Softswitch)

IP Network

with IP based

controlSS7

Network

PSTN

Media

Server

Feature/

Application

Server

Broadband IAD

IP PBX

IP Wireless Device

Border Agent/

Session Controller



Media

Gateway

Signaling

Gateway

Softswitch Architecture

MediaGateway

Controller

(Softswitch)

IP Network

with IP based

controlSS7

Network

PSTN

Media

Server

Feature/

Application

Server

Broadband IAD

IP PBX

IP Wireless Device

SOFTSWITCH

Border Agent/

Session Controller



Basic Definitions

> Media Gateway - the switch portion of the Class 5switch. Switching technology has advanced

tremendously over the past few years, and vendorscan easily produce inexpensive media gatewaysthat can handle many more calls in a smaller sizethan Class 5 switches.

> Media Gateway Controller - runs the call controland application-level calling features in a serverthat supports easy software upgrades andexpansion of features. The media gateway

translates between circuit-switched voice trafficand packet-based traffic. It is also called the "callagent," and it controls the media gateway.



Basic Definitions

> Signaling Gateways - convert and/or relay network

SS7 call signaling between the circuit network andthe packet backbone.

> Media Server - a device for storing and servingstreams of data to a feature server, media gatewayor media gateway controller.



Basic Definitions

> Feature Servers - provide less frequently used but

more processor-intensive services such asvoicemail, call center routing, advanced billing andthe like, freeing the media gateway controller tofocus on call control functions.

> Session Border Controllers - provide support fortelecom network transitions. Most notably issupport for NAT traversal and state managementthrough firewalls for SIP sessions, and may

support billing, QoS and other managementfunctions.



Class 5 (Core) versus

Local Exchange

>

Class 5 Softswitches> Have existed for several years

> Switch long haul, intra and inter-lata traffic (tandem)

> Can be feature-ignorant for the most part

> Relatively simple to program and maintain

> Local Exchange Softswitch

> Relatively new

>

Provide local switch AND calling features> Extremely complex to program and maintain (today)



What Must a Local

Exchange Softswitch Do?

> But, there is much much more to a softswitch…

> Move a voice session from a hard-wired, circuit-switchedconnection to a software-serviced session and you can addvalue…

> Adjust the quality of the call…echo cancellation, jitter buffering, QoS,

latency adjustment

> Process the call content…record it, translate it, transcribe it, store it forreplay

> Distribute the call content…multicast, call routing

> Add multimedia services…video, text messaging, subtext> Bill for differentiation…quality of call, content of call, priority of the call

Service Differentiation and Lower Costs



New Services Enabled by

Local Exchange Softswitch

> Distributed multi user gaming

> Virtual reality

> Web pages and applets

> Links in e-mails

> Web IVRs

> Click-to-dial

> Directory services

> Video conferencing

> Instant messaging

> Voicemail notifications

> Stock notifications

> Callback notification

> Calendars

> Pre-arranged conference calls

> Unified messaging

> Voicemail to e-mail



What is SIP and Why is it Hot?

> Session Initiation Protocol enables a low cost, well

understood, cohesive, OPEN session establishmentand control method over IP for streams of media,including voice and video

> Leverages widely deployed underlying technologies

such as DNS> Broadly available, open source SIP protocol stack

makes VoIP using SIP commonplace

> Lots of open source applications that use SIP

> Competition to embellish and support open stacks

> Consumers embrace open source concept

> When you hear SIP think “open source”



What Does Open Source

VoIP Need to Take off?

>

Support!!!> There are many open source projects for

everything from IP PBX to SIP Proxy/redirectors toQoS managers to media servers

> The applications are well written and verycomplete, but…

> They are very complex. Complex protocols,

complex configurations, complex interfaces> Need for new channels of support are clear



Opportunities Abound

>

Voice over Broadband> Cable operators

> DSL operators

> Fixed wireless> Power line operators

> Hosted IP PBX

>

Enterprise PBX



www.pt.com

The Elements of

Local Exchange Softswitch



Softswitch Hardware

Building Blocks

Computing Elements• Intel ® -based SBCs• Rear panel transition boards• Network and packet processors

SS7 Elements• Signaling gateway blades

• Rack components• SS7 MTP-2 cards

Platform Elements• Packet-based chassis platforms• Layer2/Layer3+ Ethernet switching/routing

• System management• Power and cooling

Software & Middleware• Linux-based software suite• System management• Media & voice processing• WAN protocols• SS7/IP signaling• High availability

Media & Voice Processing

• DSP resource HW platforms• Development tools• Universal port functionality• PTMC, PCI and CompactPCI ®

I/O & Communications• T1/E1/J1• T3• Sync/serial access• WAN/LAN communications

servers



Media Server

Announcements DTMF Audio Bridging Recording

Speech

Recognition Text to Speech Fax Video

Functions of a Media Server



Media Server

Media Server Services•DTMF detection and announcement playing

•Speech recognition and speech synthesis•Conditioning of audio signals, echo and noise suppression•Bridging for audio and video•Transcoding for compressed services•Recording and playback•Streaming of audio and video

D

e c o d i n g

D e- p a ck e t

E

n c o d i n g

P

a ck e t i z e

RTP Media

Stream

Feature ServerSpeech Server ManagementStorage

RTP MediaStream



Media Server

Ethernet SwitchEthernet Switch


ISMISM ISMISM

Storage ControllerStorage Controller

Vocoding/EncodingVocoding/Encoding

DTMF Detection/ControlDTMF Detection/Control

Streaming ServerStreaming Server

TDM Call BridgingTDM Call Bridging



Feature/Application Server

QoS Management BillingFault Detection/

Response

Advanced Call

Routing

Web Client

Interface

Advanced

Conference Features

Unified Messaging

Voicemail Call Center

Functions of a Feature/Application Server



Feature Server



ISMISM ISMISM


Vocoding/EncodingVocoding/Encoding – – Voice RecVoice Rec

IVR DTMF Detection/ControlIVR DTMF Detection/Control

Converged MessagingConverged Messaging

Video Conference ServiceVideo Conference Service



Media Gateway Controller

Call Set Up Call Tear Down In Call Features Call Agent - SIP

Call Agent – H.323 Audit Sessions Restart Multipoint

Functions of a Media Gateway Controller



Components

> Media gateway controller

> Provides call signaling,control and processingintelligence to the gateway

> Sends and receivescommands to/from the

gateway> Gateway

> Provides translations betweencircuit-switched networks andpacket-switched networks

> Sends notification to the callagent about endpoint events

> Executes commands from thecall agents

Media GatewayController(MGC)

Media GatewayController(MGC)

SIPH.323

MGCP orMegaco

MGCP orMegaco

Media Gateway(MG)

Media Gateway(MG)



Media Gateway Controller



ISMISM ISMISM


TDM Link to MGTDM Link to MG

MGCP TranslatorMGCP Translator

Call ControlCall Control -- IPPBXIPPBX

Signaling GatewaySignaling Gateway



Media Gateway

Protocol Translation Physical InterfaceVoice Encode

Decode

Functions of a Media Gateway



Media Gateway



ISMISM ISMISM

Voice Decoding (IP Net In)Voice Decoding (IP Net In)Voice Encoding (PSTN In)Voice Encoding (PSTN In)

TDM Link to PSTNTDM Link to PSTN

TDM Link to MGCTDM Link to MGC



Session Border Controller

Protocol Translation QoS Policy Security

Billing/

Traffic Reporting

Lawful

Interception

IP Phone

Management Failover Reroute

Functions of a Border Agent/Session Controller

NAT Traversal



Session Border Controller



ISMISM ISMISM

TurnTurn

STUNSTUNSBCSBC

CALEA/Lawful InterceptCALEA/Lawful Intercept



Because it is all software, functions

can be combined into one hardware platform



ISMISM ISMISM

Media Gateway ControllerMedia Gateway Controller

SBC/STUN/TURNSBC/STUN/TURN

Media ServerMedia Server

CALEA/Lawful InterceptCALEA/Lawful Intercept

Media GatewayMedia Gateway

Feature ServerFeature Server

Signaling GatewaySignaling Gateway



Conclusion

> A softswitch is a platform for routing anddelivering multi-media services on a packetswitched network (IP)

> A softswitch replaces traditional circuit switching

>

A softswitch serves as the basis for a whole newrange of product offerings

> Softswitches have existed for over a decade, butare only now finding popular adoption thanks in

large part to SIP> Softswitches are enabling competitive carriers to

enter the market…VoDSL, VoCable, VoWiFi



Thank you!

For more information,visit www.pt.com or contact us at:

585-256-0200 or [email protected]

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