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The Essential Developer’s Toolkit for Designing Enterprise IP Telephony

Debbie GreenstreetDirector, Product Management

Texas Instruments

Internet Telephony ExpoFebruary 2003

Page 2

Agenda

Enterprise IP Telephony IP Telephony Architecture Key Functional Attributes Solution Components

Page 3

Enterprise Network Telephony Evolution

PacketNetwork

IP enabled PBX

IP PBX

LAN

Server

SME Gateway

PBX

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Enterprise Gateway Block Diagram

ENETPHY

RISC

FLASH SDRAM

T1/E1FRAMER T1/E1 TrunkDSPSRAM

VoIP Functionality

Network/PBX Functionality

NetworkSwitch/Router

WAN ENETPHY

ENETPHY

LAN

PBXCall Services

T1/E1 Trunk

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Enterprise IP Phone Block Diagram

LAN RJ45 PC RJ45DEVICE HOST

User Interface

Memory Interface

Color Graphics

Keypad

Speaker

Microphone

HandsetRJ11

HeadsetRJ11

Ethernet InterfaceUSB Interface

FLASH

SDRAMLCD I/F

Audio I/F

Keypad I/F

USB I/FOR

Memory Intf IP PhoneChipset

Voice Interface

Network Interface

Processor and Associated Logic

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Voice

VAD

GSM

PacketInterface

Signaling

EchoCanceller

Fax Relay

TxGain

Caller ID

ToneDetection

Signaling Support

VoiceCodec

VoicePlayout

PacketVoice

Protocol

RxGain

Fax Data Pump

Fax ProtocolRelay InterfaceT.30 Fax

NetworkDriver

PCMInterface

ToneGener-ation

CODEC

SLIC

CONF

VoIP Signal Processing Functional Components

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VoIP RISC Software Functional Components

Hardware Abstraction Layer

DSP Interface

Application Services Layer

Ethernet Drivers

IP

TCP/UDP

Telephony

Hardware

Abstraction Layer

H.323

Protocol

CAS/CCS Signaling

User

Interface Unit

SIP

Protocol

Call Control

RTOS

Supplementary Services

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Real-Time Fax Relay

FAX signal detection Demodulation of the fax transmission and extracts the fax

data Remodulation of the fax data for transmission to the

receiving fax machine FAX protocol processing

eg, T.30 protocol

Network Protocol Processing Packetizing/depacketizing T.38 UDP (TCP) Jitter control Error recovery

PacketNetwork

64K bps

14.4 Kbps

64K bps

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Echo Canceller

Functions Removal of echo from frame of PCM samples Doubletalk detection Acoustic Echo cancellation

Important Attributes Convergence time (initial/updates) - time to train on the

echo Convergence on narrowband signals (e.g., MF/DTMF

tones) Suppress echo on DTMF digits Doubletalk detection Performance with high background noise - can cause

instability and loss of echo cancellation

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Network

Interface

PacketNetwork

Gateway Product

DigitalT1/E1

T3

OC1/OC3

PhysicalInterfaces

Analogulaw

alaw

linear

pulse dialing

2W/4W

loop start

ground start

gain control

ToneInterfaces

Tone GenerationDTMF

Call Progress Tone

Tone DetectionDTMF

V.21

Call Progress

MF (R1, R2)

Modem Tone

DTMF ToneRelay

SignalingInterfaces

CASFXSFXO

E & MTransparent

CCSQ.931QSIG

Transparent

Voice/FaxProcessing

EchoCancellation

VAD

VoiceCoding

Voice Playout

Fax ModemV.21

V.27terV.29V.17V.33

Interoperability - Telephony & Fax Challenges

phone

PBX

CentralOffice

KeySystems

modem

fax

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Telephony

Interface

Protocol

Stacks

ATM Networks

Frame Relay Networks

IP Networks

H.323Gateway

PC w/H.323 Node

Frame RelayGateway

ATMGateway

Interoperability - Packet Network

Network ManagementInterface Functions

Gateway Product

H.323NetworkProtocolInterface

FRF.11NetworkProtocolInterface

ATMStandard In WorkProprietary Today

Address Translationand Parsing

Fax Relay/Advanced Local

Processing

Signaling TranslationCAS H.323/FRF.11/ATMCCS H.323/FRF.11/ATM

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Jitter (Variable Delay) Voice/Fax

Key Features for Robust Playout Buffer:•Adaptable playout buffer including:

•Programmable buffer size•Dynamic buffer sizing•Jitter buffer real-time statistics•Fax - large jitter buffer to reduce the chance of lost packets

PlayoutBuffer

GatewayProduct

GatewayProduct

Packet Network

Variations in Packet Inter-arrival Rate•Changes in network load•Variations in routing paths•Variable queuing delays

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Packet Loss Voice/Fax

Lost Packets Due to:• Network congestion/performance• Network architecture• Improper jitter buffer size• Software not designed for peak load

65 4

3

2 1

PlayoutBufferPacket Network

Lost Lost

Potential Causes of Packet Reordering:• Network congestion/performance• Network architecture

Voice Software Must Provide:• Lost packet compensation for all codecs• Lost packet statistics• Peak MIPS design philosophy

Fax Software Must Provide:• Control packet redundancy to correct for lost packets• Advanced local processing to negate the effects of network problems• Very high call completion rates (100% at 5%; 97% at 10)

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VoIP Quality Monitoring

What happens if it doesn’t sound good…. Telephony tools

Support production lab testing

LAN, packet network tools Don’t capture voice QOS problems

Need passive monitoring tools Accurately estimate user perceived quality Measure live VoIP calls, not sample test calls Isolate and diagnose packet network quality problems

Separate from signal processing quality problems.

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Other Features to Consider

Security Often mentioned, but no common standard yet CableLabs including security for Voice over Cable

IPSEC for signaling

AES for voice packets

Wireless LAN Natural progression from data network popularity Business office applications Consumer opportunities in Asia/Japan

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Issues in Standards-Based Technologies

New emerging markets and technology Need for interoperability among vendors, providers Standards bodies produce comprehensive specifications

No way to avoid infringement Compliance requires use of third party IP Work-arounds/design-arounds not possible

Infringement is easily identifiable If you are “in” a particular area you are infringing Website searches flag product offerings

Potential liability is uncertain Validity/Invalidity of claimants’ IP Claimants may have IP but no pricing structure

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Company Profiles Affect Risk and Response

Three categories of companies at risk Technology providers Original equipment manufacturers End users

Location in the “food chain” affects both risk and response

Technology Providers

Service Providers

End

Users

OEMManufacturers

IP Claim #n

IP Claim #1

Example: Sum = $9/port

No Licensing, Indemnification $9/port

Non-Payment can Result in Enjoinment

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VoIP Product Development Checklist

Time to Market Goal Product schedule Opportunity costs

Internal Resources How many Expertise

Product Differentiation Corporate expertise Market needs

Risk Assessment Technology Intellectual property Scalability Feature growth

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VoIP Toolkit – Silicon

UniversalSerialBus

ReducedInstruction

SetComputer Processor

DigitalSignal

Processor

AnalogEncoderDecoder

SubscriberLine

InterfaceCircuitry

DSPRAM

EthernetSwitch

SynchronousDynamicRandomAccessMemory

ENET MediaAccessControl

ENETPhysicalInterface

PeripheralComponent

Interconnect

802.11

InternetProtocolSecurity(IPSEC)

ENET MediaAccessControl

ENETPhysicalInterface

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IP Network

HardwareDSP SoftwareTelephony

Hardware

VoIP Toolkit - Software

Hardware Abstraction Layer

DSP Interface

Application Services Layer

Ethernet Drivers

IP

TCP/UDP

Telephony

Hardware

Abstraction Layer

H.323

Protocol

CAS/CCS Signaling

User

Interface Unit

SIP

Protocol

Call Control

RTOS

Supplementary Services

Applications

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VoIP Toolkit – Board Level

Options Board level VoIP

functionality with common interface, eg PCI, for insertion in larger system

Basic level of core VoIP software often included

IP phone reference design

Benefits Board level design

(hardware and software) complete

Reduces hardware and software resources requirements

ENETPHY

RISC

FLASH SDRAM

T1/E1

FRAMER

T1/E1 TrunkDSPSRAM

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Toolkit Questions to Ask

Silicon What hardware interfaces are required What level of functional integration makes sense

Software What RTOS model makes sense Protocol source

VoIP technology provider

Third party expert

Proprietary solution

Call Control, Supp Services, etc How much is needed, uniqueness, expertise

Applications model Feature differentiation

Development/test tools

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Your VoIP Product - Pulling It All Together

Enterprise IP Telephony Requirements Variety of features, protocols – what is right for your product Market, cost goals Feature differentiation

Evaluate Development Options Internal resources, expertise Off the shelf products

Tools Available Hardware

Chip sets, boards, reference designs Software

RTOS Protocol stacks Call control, supplementary service

Don’t forget test, quality of service, serviceability