According to the Department of Homeland Security (DHS), the Internet sector is a collaboration between the information technology and communications sectors. It deals primarily with virtual applications such as information technology systems and the transmission of communications. Companies belonging to this sector specialize in the creation, distribution and exchange of digital information. Internet-based companies such as Amazon, Google, Facebook, Ebay and CISCO are part of this sector. As a hybrid of two critical infrastructure sectors, the Internet sector can be considered a complex and diverse environment that serves an essential function in society.