Transcript ppt
Netergy - Stanford - VoIP
A Show-and-Tell After the First 12 Month
Niko Färber, Yi Liang, Mack Hashemi
Bernd Girod, Balaji Prabhakar
Growth in VoIP Traffic
VoIP is one of the fastest-growing technologies in communications
900% 1998-1999
5000% 1999-2004
2004
135 billion
minutes
1999
2.7 billion
minutes
1998
310 million
minutes
Source: IEEE Spectrum, May 2000
Nikolaus Färber
Netergy – Stanford - VoIP
Scenario
LAN
Host
S
IP Phone
R
T2
WAN
Legacy LANs often do not support priority queuing mechanisms
DiffServ in Internet backbone is still evolving
VoIP has to deal with best-effort service of IP
Use Netergy’s Audacity T2 as platform for VoIP deployment
Nikolaus Färber
Netergy – Stanford - VoIP
Netergy Networks’ Audacity T2
Highly integrated OEM solution
Single chip, minimal extension
components
Two Ethernet ports
Local PC
Network
Audio functionality
G.711, G.72x
Echo cancellation
Comfort noise
VoIP software stacks
Source: www.netergynet.com
Nikolaus Färber
H.323
MGCP
SIP
Netergy – Stanford - VoIP
Networked Multimedia
Make Application
Network friendly
Make Network
Application friendly
best-effort
VoIP
Signal Processing
Networking
Improve tolerance to
delay variations and loss
Adaptive playout
Loss concealment
Control traffic on LAN
to reduce delay variations
and loss
Reduced TCP window size
exploit interactions,
strength, weaknesses
Nikolaus Färber
Netergy – Stanford - VoIP
Agenda
10:30 Welcome
10:45 Niko Färber
Reduced TCP Window Size for VoIP
in Legacy LAN Environments
11:30 Yi Liang
Adaptive Playout Scheduling
Using Time-Scale Modification
12:30 Lunch at Faculty Club
13:30 Mack Hashemi
Netergy Network’s Perspective,
Open Issues, and Future Work
14:30 End
Nikolaus Färber
Netergy – Stanford - VoIP