Network Functions
The present document defines network functions which are necessary to support services and facilities provided by PLMNs. A summary of the network functions is given in Table 1, where also an indication is given whether the network must support the function. The table also indicates whether or not a function requires internetworking signalling between PLMNs (i.e. use of Mobile Application Part, Technical Specification GSM 09.02).
All functions require signalling on the radio path as specified in Technical Specification GSM 04.08.