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Broadband VoIP Solutions - TMCnet

VIEWS: 7 PAGES: 23

									The Essential Developer’s Toolkit for Designing
           Enterprise IP Telephony

               Debbie Greenstreet
          Director, Product Management
                Texas Instruments

               Internet Telephony Expo
                    February 2003




                                             Page 1
                      Agenda

u   Enterprise IP Telephony
u   IP Telephony Architecture
u   Key Functional Attributes
u   Solution Components




                                Page 2
Enterprise Network Telephony Evolution


                                                      Server




                        Packet
                        Network
                                  SME Gateway




IP PBX
           IP enabled                           PBX
              PBX




    LAN



                                                         Page 3
       Enterprise Gateway Block Diagram

WAN                          Network                PBX          T1/E1 Trunk
             ENET
             PHY           Switch/Router       Call Services


              ENET
              PHY



                                               FLASH      SDRAM
                                        RISC
                 ENET
                 PHY



                                                      T1/E1
      LAN           SRAM            DSP              FRAMER       T1/E1 Trunk



                                                    VoIP Functionality

            Network/PBX Functionality

                                                                               Page 4
     Enterprise IP Phone Block Diagram
                                                                            User Interface


           Processor and                                                    Color Graphics
          Associated Logic
Memory Interface
                                                              LCD I/F
SDRAM                                                                               Keypad
                           Memory Intf
                                               IP Phone       Keypad I/F
                                                Chipset
 FLASH                                                          Audio I/F




              OR
                               USB I/F                                      Voice Interface

     USB Interface                       Ethernet Interface                                Microphone
                                                                                           Speaker
                                                                                    RJ11   Handset
     DEVICE        HOST                  LAN RJ45   PC RJ45                         RJ11   Headset

                     Network Interface                                                         Page 5
VoIP Signal Processing Functional Components

                      Fax Relay           Fax Data                        Fax Protocol
                                           Pump            T.30 Fax
                                                                         Relay Interface




                      Voice


  SLIC
            PCM
          Interface     Echo          Tx             VAD                            Packet    Network
                      Canceller      Gain     CONF                                  Voice
                                                                Voice                          Driver    Packet
                                                                Codec              Protocol             Interface
  CODEC
           Tone                                                           Voice
          Gener-                                                         Playout
           ation                                       Rx        GSM
                                                      Gain




                      Signaling
                                                     Signaling Support
                                Tone
                              Detection

                                  Caller ID
                                                                                                                    Page 6
VoIP RISC Software Functional Components




                                                 Supplementary Services
 CAS/CCS Signaling           Call Control

                                                    H.323        SIP
                    Application Services Layer     Protocol   Protocol
     User
 Interface Unit
                                                       TCP/UDP
                          DSP Interface
                                                          IP
   Telephony
                                                    Ethernet Drivers
   Hardware
Abstraction Layer
                    Hardware Abstraction Layer
                                                         RTOS



                                                                          Page 7
                     Real-Time Fax Relay

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

  data
u Remodulation of the fax data for transmission to the

  receiving fax machine
                                 u Network Protocol Processing
u FAX protocol processing
                                     n Packetizing/depacketizing
    § eg, T.30 protocol                  n T.38 UDP (TCP)
                                         n Jitter control
                                         n Error recovery




                           Packet
                           Network
           64K bps                                  64K bps
                                                              Page 8
                             14.4 Kbps
                        Echo Canceller

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

                                                                  Page 9
   Interoperability - Telephony & Fax Challenges

          Gateway Product

 phone           Physical             Tone           Signaling       Voice/Fax
                Interfaces         Interfaces        Interfaces     Processing
                                                                                   N
  fax             Analog        Tone Generation         CAS           Echo         e
                     ulaw              DTMF              FXS       Cancellation    t
                     alaw       Call Progress Tone       FXO                       w
modem                                                   E&M                        o
                    linear
                                                     Transparent       VAD         r
                pulse dialing
                   2W/4W                                                           k
                 loop start     Tone Detection                         Voice           Packet
                                      DTMF                            Coding       I   Network
 PBX            ground start
                gain control           V.21                                        n
                                  Call Progress                                    t
                  Digital                               CCS        Voice Playout
                                   MF (R1, R2)                                     e
  Key             T1/E1                                 Q.931
                                  Modem Tone                                       r
Systems            T3                                   QSIG
                                                                    Fax Modem      f
                                                     Transparent
                 OC1/OC3          DTMF Tone                            V.21        a
                                    Relay                             V.27ter      c
                                                                       V.29        e
Central                                                                V.17
Office                                                                 V.33

                                                                                       Page 10
       Interoperability - Packet Network

                                                             H.323
                                                            Gateway
Gateway Product

   T                                                   IP
               Network Management                                           PC w/
   e                                                Networks                H.323 Node
   l            Interface Functions
                                                P
   e                                            r
   p                               H.323        o          Frame Relay
   h                                            t            Gateway
       Address Translation       Network
   o                                            o
   n      and Parsing            Protocol       c
   y                             Interface      o   Frame Relay
                                                l     Networks
                                FRF.11
   I Signaling Translation                      S
   n CAS ® H.323/FRF.11/ATM     Network
                               Protocol         t
   t CCS ® H.323/FRF.11/ATM                     a
   e                           Interface        c                  ATM
   r                                            k       ATM       Gateway
   f                                            s     Networks
          Fax Relay/              ATM
   a
        Advanced Local      Standard In Work
   c
   e      Processing        Proprietary Today




                                                                               Page 11
              Jitter (Variable Delay) Voice/Fax


Variations in Packet Inter-arrival Rate
  •Changes in network load
  •Variations in routing paths
  •Variable queuing delays
                                                                                  Gateway
                                                                                  Product
Gateway                              Packet Network
Product                                                                 Playout
                                                                         Buffer




 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
                                                                                            Page 12
                      Packet Loss Voice/Fax


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

                                                                    Playout
                                        Packet Network              Buffer

                                    5      4         2      1
                               6                 3
                        Lost                             Lost

Voice Software Must Provide:        Fax Software Must Provide:
     • Lost packet compensation for      • Control packet redundancy to correct for lost packets
     all codecs                          • Advanced local processing to negate the effects of
     • Lost packet statistics            network problems
     • Peak MIPS design philosophy       • Very high call completion rates
                                           (100% at 5%; 97% at 10)
                                                                                        Page 13
                VoIP Quality Monitoring

u   What happens if it doesn’t sound good….
    § Telephony tools
       w Support production lab testing
    § LAN, packet network tools
       w Don’t capture voice QOS problems

u   Need passive monitoring tools
    § Accurately estimate user perceived quality
    § Measure live VoIP calls, not sample test calls
    § Isolate and diagnose packet network quality problems
       w Separate from signal processing quality problems.




                                                             Page 14
            Other Features to Consider

u   Security
    § Often mentioned, but no common standard yet
    § CableLabs including security for Voice over Cable
       w IPSEC for signaling
       w AES for voice packets

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




                                                          Page 15
Issues in Standards-Based Technologies
u   New emerging markets and technology
    §   Need for interoperability among vendors, providers
    §   Standards bodies produce comprehensive specifications

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

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

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


                                                                Page 16
Company Profiles Affect Risk and Response
 u   Three categories of companies at risk
      §   Technology providers
      §   Original equipment manufacturers
      §   End users

 u   Location in the “food chain” affects both risk and
     response
     IP Claim #1



                                                                  Service
                             Technology          OEM             Providers
                              Providers       Manufacturers        End
                                                                   Users


                                      No Licensing,            Non-Payment can
     IP Claim #n                 Indemnification  $9/port     Result in Enjoinment
                                                                             Page 17

Example: Sum = $9/port
        VoIP Product Development Checklist

u   Time to Market Goal
    § Product schedule
    § Opportunity costs

u   Internal Resources
    § How many
    § Expertise

u   Product Differentiation
    § Corporate expertise
    § Market needs

u   Risk Assessment
    § Technology
    § Intellectual property
    § Scalability
    § Feature growth
                                             Page 18
                     VoIP Toolkit – Silicon
                                           Universal
                                             Serial
802.11
                                               Bus
Internet
Protocol                                    Peripheral
Security                                     Component
 (IPSEC)                                   Interconnect
                                                  ENET
           Synchronous                            Media
                                                             ENET
             Dynamic           Ethernet          Access
                                                Control
                                                           Physical
                                                          Interface
              Random                                         ENET
              Access            Switch            ENET
                                                  Media
                                                           Physical
                                                          Interface
              Memory                             Access
                                                Control




    Reduced
  Instruction                   Digital          Analog       Subscriber
                         DSP                                      Line
      Set
                         RAM
                                 Signal         Encoder        Interface
   Computer                                     Decoder        Circuitry
                               Processor
   Processor
                                                                  Page 19
                       VoIP Toolkit - Software


                                 Applications


                                                 Supplementary Services
 CAS/CCS Signaling           Call Control

                                                    H.323           SIP
                    Application Services Layer     Protocol    Protocol
     User
 Interface Unit
                                                       TCP/UDP
                          DSP Interface
                                                          IP
   Telephony
                                                    Ethernet Drivers
   Hardware
Abstraction Layer
                    Hardware Abstraction Layer
                                                         RTOS

 Telephony                                             IP Network
                         DSP Software
  Hardware                                              Hardware
                                                                          Page 20
              VoIP Toolkit – Board Level
u   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

u   Benefits
    § Board level design
      (hardware and software)                     FLASH      SDRAM
      complete                     ENET
                                   PHY
                                           RISC
    § Reduces hardware and                                           T1/E1
                                                          T1/E1
      software resources            SRAM   DSP        FRAMER
                                                                     Trunk
      requirements


                                                                     Page 21
              Toolkit Questions to Ask

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

u   Software
    § What RTOS model makes sense
    § Protocol source
       w VoIP technology provider
       w Third party expert
       w Proprietary solution
    § Call Control, Supp Services, etc
       w How much is needed, uniqueness, expertise
    § Applications model
       w Feature differentiation
                                                         Page 22
       w Development/test tools
Your VoIP Product - Pulling It All Together
u   Enterprise IP Telephony Requirements
    § Variety of features, protocols – what is right for your product
    § Market, cost goals
    § Feature differentiation

u   Evaluate Development Options
    § Internal resources, expertise
    § Off the shelf products

u   Tools Available
    §   Hardware
         w Chip sets, boards, reference designs
    §   Software
         w RTOS
         w Protocol stacks
         w Call control, supplementary service

u   Don’t forget test, quality of service, serviceability
                                                                        Page 23

								
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