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Host Media Processing:What We’re Talking About
Using a general-purpose computing platform
To create a telephony application
Market Trend:Host Media Processing
• Lower acquisition costs, sometimes
• Lower provisioning and maintenance costs
• Eliminate special hardware associated costs
• More failure recovery options
HMP Reliability Economics
1 DSP platform with 480 ports
4 HMP platforms with 480 ports
1 Failure = 480 ports 1 Failure = 120 ports
HMP Application Economics
• ~ $4k for 1U Dual Xeon• 120 application sessions rated capacity ~ $33 per session HW cost
• Reduction in total cost of ownershipo no platform integration and testo no special hardware inventory, tracking,
failures, replacements, repairs, tech support
Distributed Media Processing
• Single large DSP media server
• Small media servers “built-in” to each application
AppServers
MediaServer
App Servers
HM
P
HM
P
HM
P
HM
P
HM
P
Primary Features
• IVR Operationso Play prompt, record and play messages, detect
DTMF tones, ASR & TTS interface
• Audio processing operationso Automatic gain control, voice activity detector,
acoustic DTMF detector
• Enhanced media serviceso Transcoding (audio and video), conferencing
• VoIP call connectionso RTP packetization, SIP signaling, encryption
Application Control Options
Application Server
Application Server
Application Server
Application Server
Application Server
Application Server
IP Media ServerIP Media ServerHMP Media Server
“Native” VOIP Application
“Native” VOIP Application
“Native” VOIP Application
IP Media ServerIP Media ServerHMP Media Server IP Media ServerIP Media ServerHMP Media Server
API
VoiceXML& CCXML
Control Protocol (SIP)
• MarkupLanguages
• API • ControlProtocol
Inside the HMP Media Server: Protocol Stacks
Host Ethernet Ports
Host IP Protocol Stack (QoS, Firewall)
UDP / SCTP TCP
RTP
HostMedia
Processing
HTTP
Scripting Engines
Media Control
Protocols
SIPMRCP
Speech Automation
Application InterfaceMedia Services
HMP StackExample Configuration for IVR
IP (QoS)
UDP
IP (Firewall)
UDP
RTPEgress IngressRTP
Packet Scheduler Jitter Buffer
Auto Gain Control
Voice Decoder
Voice Activity Det.
Tone Detector
RTP Stream Switching
Media Processing
RecordPlay
Application Interface
Packet Processing
Voice Activity Det.
Tone Generator
Voice Encoder
Gain Control
Operating System
API / IVR
Quality of Service – Why?
• Data Applicationso Reliable delivery
without error; timing is not critical
o Bursty, unpredictable bandwidth consumption
o Nonlinear performance degradation near bandwidth saturation
time
bandwidth
bandwidth
time
• Voice Applicationso Timely delivery is
critical; errors can be tolerated
o Predictable bandwidth consumption
o Linear, well distributed performance degradation near bandwidth saturation
Quality of Service – What?
Jitter Increase or Packet Loss Events
Available Bandwidth
Voice Class
Data Class
time
Voice Coder Performance
20 ms
30 ms
10 ms
1.0 ms
0.75 ms
DelayTime
4.2
4.0
4.2
4.2
4.4
Mean Opinion Score (1-5)
6.3 kbpsG.723.1
TransmissionBandwidthCoder
15 kbpsiLBC
8 kbpsG.729a
16-32 kpbsG.726
64 kbpsG.711
Voice Coder Resiliency
Mean Opinion Score
1.5
2.0
2.5
3.0
3.5
4.0
4.5
No Loss 5% Loss 10% Loss
Packet Loss
iLBC
G.711
G.723.1 G.729A
Native RTP File Recording
ContentStore
File Stream withEncapsulated RTP
• Improve the quality of recordings
• Reduce the cost of transcoding
VoIP Callers
G.711 G.726 G.723 G.729
HMP
Application
Types of Attack or Misuse
Source: IDC, 2003 CSI/FBI Computer Crime and Security Survey
0 10 20 30 40 50 60 70 80 90
Percentage Responding to Survey
Active Wiretap
Telecom Eavesdropping
Telecom Fraud
Financial Fraud
Sabotage
Theft of Property Information
System Penetration
Denial of Service
Insider Unauthorized Access
Laptop
Insider Abuse of Network
Virus
SECURITY IS YOUR RESPONSIBILITY !!!
• An HMP platform is a computer like any other
• It is vulnerable to many Internet security threats
• The application developer is responsible for building secure applications!
Kernel vs. User-Space Implementation
• Kernel • User-space
o HMP exists in the same process space as the applications
o A critical failure in the HMP stack can crash the server
o Hard to isolate HMP problems from application problems
o HMP exists in it’s own process space; the service can be stopped
o A critical failure in the HMP stack won’t destabilize the server
o HMP problems are isolated from application problems
HMP Density Roadmap
0
500
1000
1500
2000
2500
3000
2003 2005 2007 2009
Nn
um
be
r o
f P
ort
s p
er
1U
Montecito (4-Way)
Tanglewood(16-Way)
Dual 2.4 GHz
Dual 64-Bit
Based on Intel CPU Roadmap
DSP vs. HMP ??
• DSPo Very high densityo High transcoding
requiremento Low power
requiremento PSTN interfaces
and signaling
• HMPo Lower densityo Need to deploy on
generalized servers
o VOIP-only
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