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