Design of SIP transformation server for efficient media negotiation

S. Pack, Kyoung Paik Eun Kyoung Paik, Y. Choi

Research output: Contribution to journalConference articlepeer-review

1 Citation (Scopus)


Voice over IP (VoIP) is one of the advanced services supported by the next generation mobile communication. VoIP should support various media formats and terminals existing together. This heterogeneous environment may prevent diverse users from establishing VoIP sessions among them. To solve the problem an efficient media negotiation mechanism is required. In this paper, we propose the efficient media negotiation architecture using the transformation server and the Intelligent Location Server (ILS). The transformation server is an extended Session Initiation Protocol (SIP) proxy server. It can modify an unacceptable session INVITE message into an acceptable one using the ILS. The ILS is a directory server based on the Lightweight Directory Access Protocol (LDAP) that keeps user's location information and available media information. The proposed architecture can eliminate an unnecessary response and re-INVITE messages of the standard SIP architecture. It takes only 1.5 round trip times to negotiate two different media types while the standard media negotiation mechanism takes 2.5 round trip times. The extra processing time in message handling is negligible in comparison to the reduced round trip time. The experimental results show that the session setup time in the proposed architecture is less than the setup time in the standard SIP. These results verify that the proposed media negotiation mechanism is more efficient in solving diversity problems.

Original languageEnglish
Pages (from-to)31-41
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2001
Externally publishedYes
EventVoice Over IP (VoIP) Technology - Denver, CO, United States
Duration: 2001 Aug 21 → …


  • Intelligent Location server
  • LDAP
  • Media Gateway
  • Media Negotiation
  • Round Trip Time
  • SIP
  • VoIP

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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