Research Of The Communication Technology Of The Automatic Message Switching In Civil Aviation

The automatic message switching network of Civil Aviation Administration of China isused by air traffic management department, airlines, airport and such civil aviation units totransfer flight data. The network plays a very important role in providing the high-qualityservice for civil aviation flight safety. Therefore, the normal working of automatic messageswitching machine is an important foundation for realization of ATC safety.This paper mainly discusses the communication of automatic message switching fromtwo angles of reliability and safety. By analyzing, we found there are some problem about thereliability in the AFTN message formats. First, there is no requirement for a function signalmessage to represent the meaning of " receipt", which causes the transmiting side can notconfirm whether the message is successfully transmitted to the receiving side. Secondly theformat itself can only be used by the automatic message switching machine to investigatewhich message does not meet the standard format, but the message which match the correctformat but has some error in text will not be recognized. Third, because the line statuschecking of the existing format is too simple, so we can only rely on system-manage software,self-developed software and other software for monitoring. In security, there is nothing aboutencryption, authentication and other items in the format.As the format and its checking mechanism belong the application level, we can considerstarting from communications technology and communications equipment to improve thereliability and security of communications. This paper analyzes the communicationstechnology and equipment which the automatic message switching network is mainly using,which including the application in automatic message switching. Based on the analysis, thispaper proposes four optimization program about reliability and security: First we use modeminstead of RS-232C in the short-distance terminal accessing to effectively reduce thetransmission error rate, the number of error messages and the time of line interruption; nextwe use XOT applications to achieve X.25instead of asynchronous for trunk to improveline-status monitoring, which can realize real-time alarm for line interruption; and then, weuse identity authentication function of modem, call verification code and callback,to enhanceshielding against illegal access, increasing the difficulty of stealing data. Finally,appling theDES encryption algorithm to automatic message switching.On the basis of ensuring thestability, reliability and real-time, we want to integrate DES into exports of automaticmessage switching system, solving the ecurity risksof Plaintext in automatic message switching and further improving the security of message transmission.