Transcript voip - KEMT FEI TUKE

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VoIP
(Voice Over IP)
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VoIP Network
 Gateway
functionality is required to adapt the PSTN
transmission to IP (the Internet Protocol)
Intranet/Internet
G/W
Analog
Local
Loop
Packet Switched
Logical Connections
G/W
Analog
Local
Loop
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Voice Gateway
 A gateway
provides:

Signaling - dial tone, call set-up etc. (H.323, MGCP, SS7)
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Conversion to IP, (often Ethernet, possibly ATM)
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Compression (G.711, G.723.1 etc.)
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Echo Cancellation
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Quality of Service (QOS)
Packet
Network
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Interfaces
Gateway Product
phone
fax
modem
PBX
Physical
Interfaces
Tone
Interfaces
Signaling
Interfaces
Voice/Fax
Processing
Analog
Tone Generation
CAS
ulaw
alaw
linear
pulse dialing
2W/4W
loop start
ground start
gain control
DTMF
Call Progress Tone
FXS
FXO
E&M
Transparent
Echo
Cancellation
Digital
Key
Systems
Central
Office
T1/E1
T3
OC1/OC3
Voice
Coding
Tone Detection
DTMF
V.21
Call Progress
MF (R1, R2)
Modem Tone
DTMF Tone
Relay
VAD
CCS
Q.931
QSIG
Transparent
Voice Playout
Fax Modem
V.21
V.27ter
V.29
V.17
V.33
N
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Packet
Network
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Voice/Fax Standards
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Voice over IP
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H.323
SS7
MGCP
SIP
TCP/IP
Tone detection
Echo cancellation (G.165, G.168)
Voice codecs
V.x modems
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Voice over Frame Relay
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Voice over ATM
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AAL2
Voice over Cable
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FRF.11
DOCSIS 1.1
MGCP
Fax over Packet
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T.37, T.38
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Inter Operability Packet Network
H.323
Gateway
Gateway Product
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Network Management
Interface Functions
Address Translation
and Parsing
Signaling Translation
CAS  H.323/FRF.11/ATM
CCS  H.323/FRF.11/ATM
Fax Relay/
Advanced Local
Processing
H.323
Network
Protocol
Interface
FRF.11
Network
Protocol
Interface
ATM
IP
Networks
P
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PC w/
H.323 Node
Frame Relay
Gateway
Frame Relay
Networks
ATM
Networks
ATM
Gateway
Standard In Work
Proprietary Today
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ITU-T Speech Coding Standards
70
64 kbps
60
Bandwidth
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G.711
40
G.726
32 kbps
G.728
G.729AB
30
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G.723
16 kbps
8 kbps
10
5.3 kbps
0
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Voice CODEC
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Subjective Voice Coder Quality
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G.711 PCM
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G.726 ADPCM
Mean3
Opinion
Score
(MOS2
)
G.728 LD-CELP
G.729
G.729AB
GSM
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G.723.1A
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5.3
6.3
8
16
32
64
Kpbs
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VoDSL (VoIP &VoATM)
IP
IP
PPP
PPP
VoIP
AAL2
AAL5
ATM
AAL5
Lifeline
POTS
AAL2
VoATM
ATM
ADSL INTERLEAVED PATH
PLVT
VoIP
ADSL FAST PATH
DSL Client
Access Network
ISP or Core
PLVT
Lifeline
POTS
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TI’s Golden Port
 Integrated
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software with simultaneous support for:
Voice - Fax - V.90 Modem - Signaling
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Network Requirements
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Scalability - products typically range from 24/30 ports
(T1/E1) to thousands of ports
Small Footprint - rack space in central offices and ISP
POPs is expensive
Power Consumption - critical for both cost and heat
Cost - cannot afford idle resources
Simultaneous voice relay, fax relay, V.90 modem
termination
Non-Blocking
Manageable - accounting and operations
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Network Efficient Utilization
Network Type
 Bandwidth Utilization
 Grade of Service

Telogy Software Provides

Choice of low bit rate codecs
 Configurable voice packet sizes (10 ms to 80 ms)
 Efficient Voice Activity Detector (VAD)
 Fax demodulation/remodulation
 Ability to restrict max fax transmission rate, e.g., 2400, 4800, 9600 bps
 Sub-Channel Multiplexing - FRF.11
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Universal Access
 PSTN Replacement requires support for Voice,
Fax and V.90 Modem
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Capital Cost

Idle Equipment
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Recurring Cost
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Discrete Trunks
Packet
Network
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Channel Density
 Multi-Instance
- ability of software to support
multiple modems in same DSP
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Old software base hard-coded for single channel operation;
difficult to migrate to multi-channel
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Software designed for multi-channel operation from its inception
results in a more robust product
 Critical
decisions on MIPS and memory vs.
modem performance tradeoffs
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Skimping here will result in a poor performing solution
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Hardware Architecture
 Multi-processor
 Maximizes scalability
 Real time call discrimination
 Eliminates the requirement for discrete trunks
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Multi Processor
T1/E1 Building Block
Digital Signal Processor(s) (DSP)
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Voice Compression
Tone Detection/Generation
Echo Cancellation
Silence Suppression
Fax Modem
V.90 Data Modem PSTN Trunks
DSP
DSP
RISC Processor
 Modem Control Processing
CISC or RISC Processor
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DSP
Ethernet
(Internet)
DSP
Telephony Protocols
Network Protocols
Management
Routing
Billing
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Dynamic Call Discrimination
 Determines
on a call by call basis if the calling “device” is a
Human, Fax Machine, or a Modem
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Tone Detection
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Flag Detection
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Called number parsing
DSP
DSP
RISC
CISC
Ethernet
(Internet)
DSP
DSP
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Echo Cancellation

Every 60 miles between the Gateway’s echo canceller and
the reflecting hybrid requires 1 ms of echo tail
480
Miles
Gateway
PBX
CO Switch
with
echo canceller
960 1,920
Miles Miles
60 Miles
1 ms
16 ms
8 ms
32 ms
Telogy Software provides selectable tail length from 8 ms to
128 ms, G.165, G.168 compliant
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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
Gateway
Product
Potential Causes of Packet Reordering:
•Network Congestion/Performance
•Network Architecture
Gateway
Product
Packet Network
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Lost
Telogy Voice Software Provides:
•Lost packet compensation for all codecs
•Lost packet statistics
•Peak MIPS design philosophy
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4
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Playout
Buffer
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Lost
Telogy Fax Software Provides:
•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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Real-Time Fax Gateway
 Emulates
the Central Office and the remote fax
machine (fax modem)
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Demodulates the fax transmission and extracts the fax data
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Encapsulates the fax data
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Transmits the fax data in packets
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Remodulates the fax data for transmission to the remote fax machine
Packet
Network
64K bps
64K bps
14.4 Kbps
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Success Factors for Fax over Packet Networks
Packet
Compensation
Fax Interface Unit
to Fax Interface
Unit Compatability
Delay
Compensation
Network
Call Stability
Fax to Fax
Interface Unit
Compatability
Jitter
Compensations
Analog
Signal Quality
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Fax Latency
Originating
FTE
FIU
Destination
FTE
FIU
Network
FTE ends
transmission and
starts T4 timer
Delay
Duration of
T.4 timer
(per T.30)
Delay
Timeout occurs
without receiving a
reply and FTE starts
retransmission of
original message.
Retransmission from
Originating FTE “collides”
with reply from Destination FTE
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Technique To Keep Call Alive
Originating
FTE
FTE ends
transmission and
starts T4 timer
FIU
Destination
FTE
FIU
Network
Delay
Duration of T.4 timer
(per T.30)
Delay
Before timeout at Originating
FTE, FIU starts sending
“preamble” fill signal in
anticipation of receiving
message over network.
Message arrives over
network. FIU remodulates
message as it is received.
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Difference Between a Good Modem and a
Great Modem
 Key Algorithms
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- where some vendors cut corners
Echo Canceller and Equalizer
 Structure, speed and level of convergence, length
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Full vs. Reduced Complexity Viterbi decoder
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Handshaking sequence
 Works reliably in channel impairment situations
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Full channel analysis
 Smart optimization techniques
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Network Management
Challenges
Quality Measurement Supervisory Measurement
 Packet Loss
 Call Accounting
 Latency
 Call Type
 Jitter
Configuration
 Address Translation
 Signaling Mode
 Network Environment
Parameters
Telogy Software Provides

Quality statistics
 Supervisory statistics
 Online configuration
 Complete SNMP MIB for VOP
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Network Management Diagnostics
VOICE MON - Voice Packet Software Monitor
PCM trace capability
Loop back capability
SIG MON - Micro Signaling Trace Monitor
Signal level measurements
Playout statistics
Real-time trace capability
Memory dump facility
Controllable levels of tracing
All significant events including state changes, etc.
Customer can route output to Monitoring System
FAX MON - Fax Software Monitor
Real-time fax trace
All significant events
Millisecond accuracy on timestamping
Compress format interpreted by PC software
V. MON - Modem Monitor
Real-time trace capability
Configuration options
Statistics
Status
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Software Scalability
What to Look For:
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Pre-integrated hardware and software scaling from One to Thousands of ports
Optimized solutions and cost for all market areas
Synchronized feature migration
Client Products
Access Products
Infrastructure Products
Telogy Software
Client Suite
Telogy Software
Access Suite
Telogy Software
Infrastructure
Suite
Low Density
Multi-Function
Multi-Channel
Multi-Function
High Density
Broad range of
capabilities
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Intellectual Property
 It’s
a Standards-Based World
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G.728, G.729, G.723.1, etc.

V.90, V.34, etc.
 Intellectual
Property
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Critical Success Factor for Marketplace Success

Now at forefront of Customer focus
 Key
Patents 101
Competitive Issue

Affects product costs

Liability
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Traditional Telephony
 Telephones
and Fax Machines connect directly with
each other over time division multiplexed circuits
Lahore
Karachi
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Central Office
 Connections
are managed by Central Office
Switches and Enterprise PBXs

Route calls onto digital trunks
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Provide billing information (Call Detail Records - CDRs)

Provide management information (Alarms, Usage etc.)
Analog
Local
Loop
Circuit
Switched
Digital
Trunks
Analog
Local
Loop
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Modems
 Analog
Modem calls are made in the same way as PSTN
voice and fax calls
Analog
Local
Loop
Circuit
Switched
Digital
Trunks
Analog
Local
Loop
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Modems and the Internet/Intranet
 PC
Client to WEB Server rather than Peer to Peer
 Many

clients connecting through each POP
Digital access trunks required to be operationally economical
 Remote Access

Servers (RAS)
An integration of Digital Modems and IP Router
POP
Packet
Network
Remote
Access Server
WEB
Server
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Basics-Analog Voice to PCM
An analog voice signal is received
The Signal is converted to a Pulse Code Modulation
(PCM) digital stream
10110101 11010011 11001001 00100100 00111100 10010011 11100001 00100100
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Basics-PCM to Frames
The PCM stream is fed into the CODEC
10110101
11010011 11001001 00100100 00111100 10010011 11100001 00100100 00111100
11010011 11001001 00100100 00111100 10010011 11100001 00100100
00111100
And Voice frames are created
Each Frame is 10 ms long (G.729a) and contains 10 bytes of “speech”
10110101
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Summary

Carrying Voice, Fax and Data over Packet networks provides the
most bandwidth efficient method of integrating divergent
technologies

While the challenges to this integration are substantial, the
expanded market addressed by Telogy’s Golden Port make
universal port implementations your best choice
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