There are many important information affecting the detailed protocol behavior both on UE and Network. How a UE or Network make variations in the details of the protocol sequence is in most case up to their implementation.. not specified by 3GPP. So usually a huge set of tests are going on in modem manufacturer and UE manufacturer.
UE Capability : UE Category, Frequency Band, Sync Signal Sequence, General Radio Resource Info, General MIMO Parameter, Duplex Mode, Preamble sequence generation algorithm. There are roughly two types of UE capability we can think of. The term (Configured UE capability, Reported UE capability) is not 3GPP term.
USIM : Network Operator's PLMN list, Subscription Information, Access Barring
Stored Information : Most recently used frequency band, PLMN, Tracking Area Code, Cell ID, S-TMSI, InterRAT Frequency Band
Information that UE needs to get: Frequency and Timing Synchronization info, System Bandwidth, Number of MIMO Antennas, Identities (C-RNTI, Physical Cell ID, Tracking Area Code), Network PLMN, Signaling & Traffic Radio Resouce, RACH_ROOT_SEQUENCE & PRACH Config.