1. Director, Product Management Internet Telephony Expo
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
PBX
Packet
Network
IP PBX
LAN
IP enabled
PBX
As mentioned earlier, corporate networks were one of the primary applications to benefit from VoIP technology. These solutions migrated from the access devices, or Small Medium Enterprise gateways to IP based solutions.
IP based PBXs
IP phones
Allied Business market report predicts that the SME IP PBX hosted business will exceed $12.7 B by the end of 2007 and that over 50% of seats shipped will by IP by 2003.
IP Centrex good market opportunities as well.

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

5. Enterprise IP Phone Block Diagram
User Interface
Color Graphics
Processor and
Associated Logic
Memory Interface
SDRAM
IP Phone
Chipset
LCD I/F
Keypad
Memory Intf
Keypad I/F
FLASH
Audio I/F
Voice Interface
Spec available
The reference design will be implemented as the TI IP Phone development and demonstration board.
Customers can use this to develop their IP Phone application code to the APIs which we will provide. Customer application code will include things like the user interface (display, speed dials, keypad control), and all the PBX type functions (call hold, forwarding, etc…)
USB I/F OR
USB Interface
Ethernet Interface
Speaker
Microphone
Handset
RJ11
Headset
DEVICE
HOST
LAN RJ45
PC RJ45
Network Interface

6. VoIP Signal Processing Functional Components
Fax Relay
Fax Data
Pump
Fax Protocol Relay Interface
T.30 Fax
Voice
SLIC
PCM
Interface
Packet Voice Protocol
Echo
Canceller
Tx Gain
CONF
VAD
Network Driver
Packet Interface
Voice Codec
CODEC
Tone Gener- ation
Voice Playout
Rx Gain
GSM
Signaling
Signaling Support
Tone
Detection
Caller ID

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

8. Real-Time Fax Relay Packet Network 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
Packet
Network
64K bps
14.4 Kbps

9. Echo Canceller Functions Important Attributes
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
Performance with high background noise - can cause instability and loss of echo cancellation

10. Interoperability - Telephony & Fax Challenges
Gateway Product
Digital T1/E1 T3
OC1/OC3
Physical Interfaces
Analog ulaw
alaw linear pulse dialing
2W/4W
loop start
ground start
gain control
phone
PBX
Central Office
Key Systems
modem
fax
Tone Interfaces
Tone Generation
DTMF Call Progress Tone
Tone Detection
DTMF V.21
Call Progress MF (R1, R2)
Modem Tone
DTMF Tone Relay
Signaling Interfaces
CAS FXS
FXO
E & M
Transparent
CCS
Q.931
QSIG
Voice/Fax Processing
Echo Cancellation
VAD
Voice Coding
Voice Playout
Fax Modem
V.21
V.27ter
V.29 V.17 V.33
Ne t wo r k
I n t e r f a c e
Packet Network
The breadth of interoperability issues are often overlooked when implementing a voice and fax over packet solution. A lot of telephony signaling standards as well as physical interfaces are involved in interface to the full range of telephony products. For a quality solution, and true interoperability, tone detection must be differentiated from the voice, and handled separately. Then, processing the subsequent signals (whether voice energy, modem tones, echo etc) has significant interoperability issues based on standards, network conditions and end station capabilities.
Animations:
5 clicks to bring up groupings.
6th click - next slide ECO symbol back to main interoperability slide

11. Interoperability - Packet Network
H.323 Gateway
Gateway Product
T e l e p h o n y I t r f a c
Network Management Interface Functions IP
Networks
PC w/ H.323 Node
P r o t o c l S t a k s
Address Translation and Parsing
Fax Relay/ Advanced Local Processing
Signaling Translation
CAS  H.323/FRF.11/ATM
CCS  H.323/FRF.11/ATM
H.323 Network Protocol Interface
FRF.11 Network Protocol Interface
ATM Standard In Work Proprietary Today
Frame Relay Gateway
Frame Relay Networks
Of course, the network interface has a tremendous set of interoperability issues surrounding standards, network type, network conditions, configuration, addressing schemes, etc. Not only is the packet network type itself important with respect to support of interoperability and standards, but interoperability with respect to configurations and conditions within that network. Address translation between packet addressing and E.164 addresses, voice and fax encapsulation schemes, translation between telephony signaling and network signaling all have significant ramifications with respect to packet network interoperability.
Animations:
3 clicks to bring up groupings.
4th click - next slide ECO symbol back to main interoperability slide
ATM Gateway
ATM Networks

12. Jitter (Variable Delay) Voice/Fax
Playout Buffer
Gateway Product
Packet Network
Variations in Packet Inter-arrival Rate
Changes in network load
Variations in routing paths
Variable queuing delays
Packet networks introduce another effect, not present in traditional TDM networks; variations in the rate which packets arrive. This jitter affects quality in both voice and fax solutions. The Golden Gateway solution provides a robust jitter buffer that provides dynamic sizing to accommodate varying network conditions. This buffer allows accumulation of enough packets to provide a constant cadence of packet playout to the user’s ear, or to the fax machine, avoiding voice and fax sample loss. Statistics on this buffer are provided to the gateway equipment for efficient use and flexible configuration. Not all solution on the market provide this important feature. Telogy can handle up to 300ms of jitter on fax calls, superior to most solutions.
Animations:
Groupings appear automatically.
Click - next slide
Hyperlink:
Action button links to QOS Issues slide
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 Lost Packets Due to:
Network congestion/performance
Network architecture
Improper jitter buffer size
Software not designed for peak load
Potential Causes of Packet Reordering:
Network congestion/performance
Network architecture
Playout Buffer
Packet Network 5 4 2 1 6 3
Lost
Lost
Another area that affects the quality of both voice and fax calls is network packet loss. Lost packets at the network level are due to network congestion, (significant activity and usage), and in some cases, insufficient or poor network architecture. Packet loss can occur at the voice/fax over packet gateway if a playout buffer to accommodate jitter is not employed, or is improperly sized. Packets may also be “lost” in a VoIP solution if the solution is not designed based on Peak MIPs performance of each of the functional elements. Telogy’s Golden Gateway is designed under a Peak MIPs assumption so that quality is not compromised under maximum operating conditions. The Golden Gateway recognizes when Packets are lost and provides such statistics for use by the gateway equipment. The playout buffer provides last packet re-play in the event of lost or missing packets. For fax systems, the control messages are transmitted three times to avoid missing packets at the receive side.
Animations:
3 clicks to bring up groupings.
4th click - next slide ECO symbol back to main QOS slide
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)

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.
If the network is architected and managed correctly, VoIP with the appropriate QOS is feasible.
Tools on the market that inject sample calls and measure. Also need to monitor the real stuff.
ITU E model, G.107 R factor essentially translates to MOS score.

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
Concern by users of voice call integrity
Concern by Law Enforcement – ie CALEA
Concern by service providers for theft of services, DOS
IETF IP sec
802.11b – 11Mbps
80211.g – 50Mbps and 11b compatible

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 End Users
Technology Providers
OEM Manufacturers
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 Ethernet Switch Digital Signal DSP RAM 802.11
Universal
Serial
Bus
Reduced
Instruction
Set
Computer
Processor
Digital
Signal
Analog
Encoder
Decoder
Subscriber
Line
Interface
Circuitry
DSP
RAM
Ethernet
Switch
Synchronous
Dynamic
Random
Access
Memory
ENET
Media
Control
Physical
Peripheral
Component
Interconnect
802.11
Internet
Protocol
Security
(IPSEC)

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

21. 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
ENET
PHY
RISC
FLASH
SDRAM
T1/E1
FRAMER
T1/E1 Trunk
DSP
SRAM

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