1. 網際網路電話系統
期末考重點整理

2. Elaborate on the advantages of separation of media and call control.
SIP Extensions:
Describe the functions of SIP INFO method.
Why should the reliability of provisional responses be supported in SIP? How to achieve it?
Elaborate on the advantages of separation of media and call control.
Compare the H.323 (SIP) with MGCP (MEGACO). DO NOT TOTALLY COPY the words in the slides.
You are asked to design a SIP-to-PSTN gateway based on MGCP. Draw the network architecture and describe the message flow for a SIP terminal calling a telephone on PSTN.
Describe the issues discussed in IETF SIGTRAN.
Explain why SCTP is more suitable for SIGTRAN than TCP or UDP.
Compare MGCP with MEGACO.
Describe the concepts of Soft-switch, and Compare Soft-switch with existing “Hard/Circuited”-switch
Briefly describe the overall approach for designing a VoIP Network.