The Essential Developer’s Toolkit for Designing Enterprise IP Telephony

1. The Essential Developer’s Toolkit for Designing Enterprise IP Telephony Debbie Greenstreet Director, Product Management Texas Instruments Internet Telephony Expo February 2003

2. Agenda • Enterprise IP Telephony • IP Telephony Architecture • Key Functional Attributes • Solution Components

3. Enterprise Network Telephony Evolution Server SME Gateway IP PBX PBX IP enabled PBX LAN Packet Network

4. Enterprise Gateway Block Diagram T1/E1 Trunk PBX Call Services WAN Network Switch/Router ENET PHY ENET PHY FLASH SDRAM RISC ENET PHY T1/E1 FRAMER T1/E1 Trunk SRAM DSP LAN VoIP Functionality Network/PBX Functionality

5. Enterprise IP Phone Block Diagram IP Phone Chipset SDRAM FLASH Microphone Speaker Handset Headset RJ11 RJ11 Keypad User Interface Color Graphics Processor and Associated Logic Memory Interface LCD I/F Memory Intf Keypad I/F Audio I/F Voice Interface USB I/F OR Ethernet Interface USB Interface DEVICE HOST PC RJ45 LAN RJ45 Network Interface

6. VoIP Signal Processing Functional Components Fax Relay Fax Data Pump Fax ProtocolRelay Interface T.30 Fax Voice SLIC PCM Interface PacketVoiceProtocol VAD CONF NetworkDriver Echo Canceller TxGain PacketInterface VoiceCodec CODEC ToneGener-ation VoicePlayout GSM RxGain Signaling Signaling Support Tone Detection Caller ID

7. VoIP RISC Software Functional Components TCP/UDP IP Ethernet Drivers Supplementary Services Call Control CAS/CCS Signaling SIP Protocol H.323 Protocol User Interface Unit Application Services Layer DSP Interface Telephony Hardware Abstraction Layer Hardware Abstraction Layer RTOS

8. 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 Real-Time Fax Relay Packet Network 64K bps 64K bps 14.4 Kbps • Network Protocol Processing • Packetizing/depacketizing • T.38 UDP (TCP) • Jitter control • Error recovery

9. 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

10. Interoperability - Telephony & Fax Challenges Gateway Product PhysicalInterfaces ToneInterfaces SignalingInterfaces Voice/FaxProcessing phone Network Interface EchoCancellation Analogulaw alawlinearpulse dialing 2W/4W loop start ground start gain control Tone Generation DTMFCall Progress Tone CASFXS FXO E & M Transparent CCS Q.931 QSIG Transparent fax modem VAD VoiceCoding PacketNetwork Tone Detection DTMFV.21 Call ProgressMF (R1, R2) Modem Tone PBX Voice Playout DigitalT1/E1 T3 OC1/OC3 KeySystems Fax Modem V.21 V.27ter V.29V.17V.33 DTMF ToneRelay CentralOffice

11. Interoperability - Packet Network Te l e p h o n y I n t e r f a c e Address Translationand Parsing H.323NetworkProtocolInterface Signaling Translation CAS  H.323/FRF.11/ATM CCS  H.323/FRF.11/ATM FRF.11NetworkProtocolInterface Fax Relay/Advanced LocalProcessing ATMStandard In WorkProprietary Today H.323Gateway Gateway Product Network ManagementInterface Functions IP Networks PC w/H.323 Node Prot o c o l S t a c k s Frame RelayGateway Frame Relay Networks ATMGateway ATM Networks

12. Jitter (Variable Delay) Voice/Fax • Variations in Packet Inter-arrival Rate • Changes in network load • Variations in routing paths • Variable queuing delays GatewayProduct Packet Network GatewayProduct PlayoutBuffer • 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

13. Packet Loss Voice/Fax PlayoutBuffer • 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) • Voice Software Must Provide: • Lost packet compensation for all codecs • Lost packet statistics • Peak MIPS design philosophy • Potential Causes of Packet Reordering: • Network congestion/performance • Network architecture • Lost Packets Due to: • Network congestion/performance • Network architecture • Improper jitter buffer size • Software not designed for peak load Packet Network 5 4 2 1 6 3 Lost Lost

14. 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.

15. 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

16. 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

17. 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 IP Claim #1 Service Providers EndUsers Technology Providers OEMManufacturers No Licensing, Indemnification $9/port Non-Payment can Result in Enjoinment IP Claim #n Example: Sum = $9/port

18. 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

19. VoIP Toolkit – Silicon Universal Serial Bus 802.11 Internet Protocol Security (IPSEC) Peripheral Component Interconnect Synchronous Dynamic Random Access Memory ENET Media Access Control ENET Physical Interface Ethernet Switch ENET Physical Interface ENET Media Access Control Reduced Instruction Set Computer Processor DSP RAM Digital Signal Processor Analog Encoder Decoder Subscriber Line Interface Circuitry

20. VoIP Toolkit - Software TCP/UDP IP Ethernet Drivers Applications Supplementary Services Call Control CAS/CCS Signaling SIP Protocol H.323 Protocol User Interface Unit Application Services Layer DSP Interface Telephony Hardware Abstraction Layer Hardware Abstraction Layer RTOS IP Network Hardware DSP Software Telephony Hardware

21. VoIP Toolkit – Board Level SDRAM FLASH ENET PHY RISC T1/E1 Trunk T1/E1 FRAMER DSP SRAM • 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

22. 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

23. 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