The CM (Cable Modem) registering message on your cable box indicates that the box is trying to register with your cable provider‘s network. It means that your cable box is attempting to establish a connection with your cable provider‘s head end equipment and is requesting service information. The CM registering message will disappear once the connection is established successfully.

Ethernet frame is a data packet used for data communications over a network. It consists of the data being transmitted, and a header which contains information about the data, such as the source and destination addresses, the frame length, and any error–checking data. The Ethernet frame is then encapsulated in an ethernet packet, and sent to its destination.

CMOS battery, also known as the Real–Time Clock (RTC) battery, is a battery used to power the CMOS memory that stores a computer‘s BIOS settings. It helps to keep track of date and time even when the computer is turned off. This type of battery typically lasts five to ten years before it will need to be replaced.

Cisco training is a series of courses offered by Cisco to teach users the basics of networking and related protocols, and prepare them for Cisco–specific certification exams. The aim of the training is to enable users to design, deploy, configure, and troubleshoot simple to complex Cisco network environments. In addition to teaching the basics, training also typically covers advanced topics such as network virtualization, Cisco Unified Communications, and network security.