The method of breaking digital messages into small fixed bundles, transmitting them along different communication paths, and reassembling them at their destination is called:

Packet switching

Explanation:

Packet switching - it is referred to as the transmission process which involved sending of packets through communication path and last reassembling them again.

The sending of packets is done by broken the digital message into required pieces for efficient transfer.

in this process, every individual parcel is sent separately.