The Stream Control Transmission Protocol (SCTP) is a reliable unicast transport protocol originally specified by the Internet Engineering Task Force (IETF) in RFC 2960. After years of implementing and testing, defects and errors in RFC 2960 were reported and later fixed in RFC 4460. Incorporating those suggested fixes, IETF revised the SCTP specification and published RFC 4960, which replaces RFC 2960. Despite of being the revised specification, the descriptions of the simultaneous open and the restart procedures are still unclear and difficult to understand. To clarify this informal specification and gain insights, we formally model and analyse the association management using Coloured Petri Nets. In particular this paper focuses on the Tie-Tag operation and the simultaneous open procedure operating over the simplest channels, First In First Out (FIFO) with no loss. Our analysis reveals errors in which both sides are in ESTABLISHED but the verification tags in both Transmission Control Blocks do not match.