The Research And Implementation Of IMS Redundancy And Restoration

Since 3 GPP R5, IMS has been one focus in telecommunication technology research. IMS makes different kinds of telecommunication skills running in a unified architecture. With version from R99 to R4 then to IMS, the Core Network architecture has been changed along. IMS is a system based on SIP signaling, independent with access technology and controlling users in home domain.The restoration skills are scarcely mentioned in R99's technical documents. In R4, lots of techniques about redundancy and restoration appear in the documents. The restoration methods in R4 often need some cutover jobs. There have been many documents about IMS restoration and they are mainly technical analysis. Because IMS restoration is based on IP routing without redundancy links, the restoration procedure may be costless and more feasible.IMS is not one service which use new techniques but one function for current IMS architecture. IMS restoration should use special mechanisms such as SIP, DNS and Diameter. In some case, the protocol may need to be extended.This passage uses "multi-nodes restoration" model. Firstly I pay attention to the layout and network element design. Combined with the analysis of IMS key procedures, I figure out one whole solution and partly modify the original network architecture. Next chapter I give the details of signaling procedure for each restoration scenario. After that I give some test results about my restoration solution. In the end it is one suggestion on "IMS Regional Restoration".