Unable to surf the internet. Campus network is a broadband multimedia network that provides teaching, scientific research and comprehensive information services for school teachers and students. In xss campus network, the lack of mac address parameters will lead to the inability to access the Internet, and professionals need to add mac addresses. The length of MAC address is 48 bits, which is usually expressed as 12 16 hexadecimal number. In the OSI model, the third network layer is responsible for IP address and the second data link layer is responsible for MAC address.