IEEE 1588
The IEEE 1588 standard has the title "Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control System", in short Precision Time Protocol( PTP). The time synchronization protocol described in it defines how many spatially distributed real-time clocks are synchronized.
These must be connected to each other via a network that uses data packets for transmission, such as Ethernet. But other packet-switching protocols that support multicast addresses can also work with the Precision Time Protocol. With Ethernet, considerable delays can occur due to the access procedure and the run times, which can be compensated with the Precision Time Protocol.
The 1588 protocol was developed by Hewlett Packard for automated measurement technology, it supports the time synchronization of the connected devices and compensates for runtime differences. The 1588 protocol is used, for example, in the LAN Extensions for Instrumentation( LXI), where it takes over the time synchronization of the connected devices.
Since both IEEE 1588 and IEEE 802.1AS were developed for synchronizing local clocks in a network and have many similarities, there are efforts to harmonize both standards.