Analysis, Design & Implementation Of SCTP In No.7 Signaling Gateway

SCTP is a next generation transport protocol; it can be used to transmit the signaling messages of NO.7 over IP.In this paper, we firstly gave an overview on the functional responsibilities and some basic concepts of SCTP. The similarities and differences between SCTP and TCP, UDP are also discussed in detail. Then we disscussed the software modules design of SCTP. We also analyzed and designed the key technologies of the implementation.COOKIE parameter is the key of the implementation of COOKIE validation mechanism in the process of association setup; we designed the data structure of COOKIE parameter, which made it possible that we implemented the COOKIE validation mechanism.Tie-Tags included as part of OOOKIE parameter play an important role in handling various unexpected initialization chunks. We also designed the value of Tie-Tags in different association statuses and illustrated how to use the Tie-Tags.As a general transport protocol, controlling and managing data transfer and data acknowledgment is a critically important part of the implementation of SCTP. We analyzed the transmission rules and the correlative issues that selective acknowledgment should think about.Finally, we introduced the association close, analyzed some potential race conditions that may occur during a graceful shutdown and described the corresponding approaches that an implementation may wish to put in place to prevent these situations.