message handling

hi, today i will finally (begin to) structure the message handling in my current work on layer 3: the message handling functions consist of: - message cration - message sending - message en-queueing - message de-queueing i deal with interfaces (SAP): - between application and call control (MNCC-SAP) - between call controll and mobility management (MMCC-SAP) - between supplementary services protocol and mobility management (MMSS-SAP) - between sms protocol and mobility management (MMSMS-SAP) - between mobility management and radio ressource (RR-SAP) - between radio ressource and layer 2 / layer 1 (let's call it RSLms-SAP) additionally there are interfaces: - between application and mobility management - between application and PLMN search - to the sim card - to the application - ... here is what i think the messages should look like. please correct me if i am wrong or if you have suggestions: MNCC-SAP: <gsm48_mncc structure> MMCC-SAP, MMSS-SAP, MMSMS-SAP: <gsm48_mmxx structure>[<L3 message*>] RR-SAP: <gsm48_rr structure>[<L3 message*>] RSL-SAP: <abis_rsl_rll_hdr structure>[<L3 message*>] * the layer 3 message consists of the gsm48_hdr structure + additional information elements. if a layer 3 message moves from call control down to RSL and even lower, the inter-layer headers are pulled and pushed. additionally there are pointers to the beginning of the headers inside the message: - l1h - l2h - l3h - layer 4 headers - layer 5 header the inter-layer messages (MMxx-SAP and RR-SAP) will have no pointer to the message structures. i think they also should not have them, since they have fixed length and are pushed at the time they are sent, and pulled at the time they are received. any suggestions? andreas