Paper Title
Data Communication Networks and Security

The objective of this paper is to evaluate data Communication Networks and Security. This paper introduces data Communication Networks which emphasize on cellular telephony, satellite networks and satellite orbits. Another important aspect of the paper is Network Security which focused on communication network base attacks, principles of cryptography, and basic technologies to prevent vulnerabilities in network security. This paper concludes that, channel is always assigned to the caller by the mobile switching center (MSC), handoff procedure in 4G networks helps signals to be transmitted from one cell to another without the notice of the caller. It was established that the major principle of cryptography was algorithm and secrecy. The algorithm makes sure that the encryption and decryption of a plaintext is not made readable by an intruder or a hacker. The secrecy ensures that the key is not made known to a third party. The basic technologies to prevent vulnerabilities in network security were mainly intrusion detection, firewall, password management, strict security polices, antivirus, and encryption. Index Terms - Communication, Satellite, Orbit, Network Security, Cryptography.