SIP based VoIP service Architecture and Comparison

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SIP based VoIP service Architecture and Comparison
INFOTECH Seminar Advanced Communication Services
(ACS), 2005 Mentor Dr.-Ing. Stephan Rupp

• Student TONG Hoang Anh
• Institute of Communication Networks and Computer
  Engineering
• University of Stuttgart

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General model for VoIP
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General model for VoIP
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Motivation

• Voice over IP expected to replace the Public
  Switched Telephone Network (PSTN)

• Challenges
• provide new, attractive multimedia service
• control of advanced features(supplementary
  services)

SIP and H323 are 2 approaches
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Protocol Stack
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Agenda

• SIP
• SIP architecture
• SIP messages
• Scenarios

• H323
• H323 architecture
• Scenarios

• Comparison and conclusion

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SIP architecture
Accept REGISTER request from client
Forward message to next hop server
UACinitiate SIP request UASreturn SIP respond
Redirect caller to destination or other server
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SIP messages

• INVITE invites a user to join a call.
• ACK confirms of the received response to an
  INVITE.
• BYE terminates the call between two of the
  users on a call.
• OPTIONS requests information on the
  capabilities of a server.
• CANCEL ends a pending request, but does not
  end the call.
• REGISTER informs a server the location of a
  user.

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Simplest peer-to-peer call setup
Bob
Alice
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SIP operation in Proxy mode
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SIP operation in Redirect mode
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Agenda

• SIP
• SIP architecture
• SIP messages
• Scenarios

• H323
• H323 architecture
• Scenarios

• Comparison and conclusion

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H323 architeture
Address Translation, Admissions Control,
Bandwidth Control, Zone Management
Enable conferencing MC multipoint call and
control signalling MP mixing, switching, and
processing of the audio, video, and data streams
H323 endpoint, originate and terminate H323
signalling and data stream (must support audio)
Data format translation, control signaling
translation, audio/video, codec translation, call
setup/termination functionality
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H323 call establishment
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H323 call control signalling
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Media stream and Media control flow
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H323 Call release
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Agenda

• SIP
• SIP architecture
• SIP messages
• Scenarios

• H323
• H323 architecture
• Scenarios

• Comparison and conclusion

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H323 vs SIP Comparison
Network components
Protocols running on terminal
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Implementation comparison
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Conclusion

• H323 is a comprehensive set of protocols, focus
  on handling voice and multimedia calls including
  supplementary services.
• SIP is a generic transaction protocol for session
  initiation, not limited to any specific media
  services.
• H.323 provides better functionality,
  interoperability and interworking (with PSTN)
  with respect to supplementary services.
• SIP has its strengths for lightweight and
  easy-implemented solutions with focus on flexible
  session initiation. SIP provides better
  mechanisms for controlling non-VoIP services.
• Two standards are approaching each other.
• In the public VoIP services, SIP is currently the
  dominent technology.

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Thank you for your attention