:::warning # <center><i class="fa fa-edit"></i> Schema of main function (first part)</center> ::: [TOC] ### Schema (first part) ![](https://i.imgur.com/Pq1KxUx.png) ### Explanation of blocks #### Initialisation of NR configuration block At this block we have to start a background system, after that load configuration modules and the last thing is to set soft modem signal handler. #### Getting information about AMF and NGAP | AMF | NGAP | | ----------------------- | ----------------------- | Automatic Mains Failure|NG Application Protocol| | AMF panels are designed to switch the electrical load of system from the normal supply to a standby supply, normally a generator, and then back when required. | Provides the control plane signalling between NG-RAN node and the Access and Mobility Management Function | #### Initialize a MSC-gen log At this block we have to initialize a OPt, after that if PDCP uses a netlink, than we have to initialize a netlink. Then we have to write some info in log about HW (hard ware) and package version #### Initialize UE PF PO and mutex lock - **UE** - *user equipment* - **PF** - *Paging Frame* - **PO** - *Paging Occasion* - **nFAPI** - *is implementation of the Small Cell Forum's network functional API or nFAPI for short. nFAPI defines a network protocol that is used to connect a Physical Network Function (PNF) running LTE Layer 1 to a Virtual Network Function (VNF) running LTE layer 2 and above.* Firstly we have to initialize a mutix function(pthread_mutex_init() function initialises the mutex referenced by mutex with attributes specified by attr), fill a block of memory with a particular value, initialises the condition variable and mutex referenced. If nFAPI gets mode, than we will see a message "NFAPI*** - mutex and cond created - will block shortly for completion of PNF connection"