Which of the following is considered a common network error?

Checksum errors are indeed considered a common network error because they occur when the data received does not match the expected value calculated from the original data. Each packet of data has a checksum value calculated at the source and included with the packet during transmission. When the packet arrives at the destination, the checksum is recalculated, and if it does not match the transmitted checksum, it indicates that an error has occurred during transmission, commonly due to issues like noise or corruption in the network. This can lead to data integrity problems and necessitates retransmission of the corrupted packets to ensure reliable communication.

Packet fragmentation, while it can lead to issues, is more about how data packets are divided and reassembled across the network rather than an error per se. Data encryption issues primarily deal with the secure transmission and confidentiality of data rather than errors resulting from the physical or logical operation of the network. Overloaded IP addresses suggest network congestion or issues with management of addresses but do not directly relate to error states in data transmission like checksum errors do.