| AAA(authentication, authorization, accounting) protocol is a kind of important protocol in Intelligent Network, RADIUS (Remote Authentication Dial-In User Service) is one AAA protocol which has been applied widely. With the development and application of telecommunication network, RADIUS which is based on UDP can not meet the security and performance requirements, DIAMETER was introduced in this background.DIAMETER protocol is based on TCP/SCTP which provides the reliable transport layer connection, and it can be treated as extension or replacement of RADIUS. IETF RFC3588 defines the basic content of DIAMETER, such as the FSM of DIAMETER connection, format of message/AVP etc. DIAMETER is widely applied in IMS(IP Multimedia Subsystem) network, 3GPP protocol family will extend the DIAMETER message/AVP as required.Intelligent Network Department of Alcatel-Lucent is responsible to develop and maintenance IMS regarding protocols, such as DIAMETER, SIP etc. So far, Alcatel-Lucent IMS applications have been widely applied. With the IMS developing, 3GPP will extend the DIAMETER protocols accordingly, in order to support new 3GPP's standard, we have to change the source code of application software. For instance we have to change the DIAMETER encoding/decoding module.After more than 3 years maintenace on DIAMETER protocol, we found a problem when we did projects retrospective review, it was that most of DIAMETER projects were focused on encoding/decoding module. Then is it possible to develop a tool to generate the code of this module? And this is the subject of the paper.Our Dev team discussed the question and made the conclusion that the project was feasible. Under this background, this paper is keen on developing a generator for DIAMETER message encoding and decoding functions library. Current implementation of Alcatel-Lucent DIAMETER stack is hand-coded, in other words, if we modify the message/AVP definitions, we will have to change the code of encoding/decoding part accordingly. It needs lots of effort to maintain the stack for message/AVP modifications requirements. This paper will develop a DIAMETER message encoding/decoding generator, when it done, the work of modifying message/AVP will be very easy. This paper will analyze the the feasibility and necessarity firstly, then describe the detailed requirements, next will give the design and implementation, at last will provide the detailed testing result. |
