What is cell ID (cell identity)?

The cell identity in GSM and UMTS is a 16bit identifier. When attached with the Location Area Identity or Routing Area Identity the outcome is termed the Cell Global Identity. Cell Global Identity (CGI) is a Base Transceiver Station globally unique identifier in cell phone networks. It comprises four sections: Mobile Country Code (MCC), Mobile Network Code (MNC), Location Area Code (LAC), and Cell Identification (CI).