Signalling System Number 7 On The Siemens Mobile D900 Switch

China government issued 3G licenses at 2009, CMCC, China Unicom and China Telecom are struggling to build 3G networks,3G subscribers are growing fast, but China's current 2G network is still dominant,2G business is still the operator's main source of income, such is not going to change in the short term,2G networks will continue to exist for a long period of time. Therefore, CCS7 based on the traditional 2G network, will be a fairly long period of time continue to exist.Siemens Mobile Switch D900 is based on traditional 2G networks, accord to CCS7 standards, has a very wide range of applications in our country. This thesis is about the CCS7 applications at Siemens D900 switch mobile.This thesis introduces the topics of the background and significance first. Then introduces the basis of CCS7, introduces the basic concepts of CCS7, China's CCS7 network architecture, seven layer model of OSI and the relationship between CCS7, a brief introduction of the MTP layer, SCCP layer, ISUP layer, MAP layer. Then introduces the Siemens Mobile Switch D900 hardware and how CCS7 comply at the Siemens Mobile Switch D900 platform.On this basis, introduces the five very typical case about CCS7 of my seven years work, these five cases are representative, is the major part of this thesis. The first case of the thesis is due to the user mobile phone SMS Center address is set incorrectly, is the user cause; The second case is due to switch to set the parameters on the Early ACM incorrect, is the switch causes; The third case is due to the Qingniu platform, fills the original called party into the Redirecting Number, Siemens Switch does not support the Redirecting Number, that belong to different manufacturers equipment understands different of the standards; The fourth case is use of CCS7,tickets and traffic statistics analysis of network phenomenon, is the integrated use of various tools; The fifth case is analysis the call loss, analysis the value of the various reasons for the failure,find out which is user behavior reason and which is the network problems. The five cases are different each other, have their own characteristics, but all these are by directly analyze CCS7, or intergrate CCS7 and ticket, traffic statistics to solve the problem. This thesis provides some of the ideas that analyze network problems by CCS7, some of the ways to solve the problem, which can provide some reference that we encountered similar problems in the future.Finally, this thesis were summarized, and a brief introduction of the R4 softswitch and IMS, proposed the direction of development of NGN of personal understanding.