A proposed presentation context consists of
- A presentation context ID (an odd integer <= 255 unique within the association)
- A SOP_Class or Meta_SOP_Class
- A list of proposed Transfer_Syntaxes
This is considered by the requesting Application_Entity which either rejects it completely or accepts, in which case the list of proposed transfer syntaxes is replaced by a single accepted transfer syntax which is then used for all communications using that presentation context.
Such subsequent communications only quote the presentation context ID, and so applications must retain copy of the agreed information in order to determine the SOP class and transfer syntax used.