This Technical Specification is divided split into two parts, Chapters 1-4 dealing with the MTP and chapters 5-7 dealing with the SCCP and its use. The MTP provides a mechanism giving reliable transfer of signalling messages. Chapters 1-4 of this Technical Specification deals with the subset of the MTP that can be used between an BSS and an MSC, which is compatible with a full MTP. The SCCP is used to provide a referencing mechanism to identify a particular transaction relating to for instance a particular call. Chapters 5-7 identify the SCCP subset that should be used between a BSS and an MSC. The SCCP can also be used to enhance the message routing for (for instance) operations and maintenance information.