Which protocol can provide timing accuracy in the nanosecond range?

The protocol that can provide timing accuracy in the nanosecond range is IEEE 1588v2, also known as Precision Time Protocol (PTP). This protocol is specifically designed for high-precision time synchronization across networked devices. It achieves this level of accuracy by utilizing hardware timestamps and other techniques that allow it to compensate for network delays, thus enabling synchronization that can meet stringent requirements necessary for applications such as telecommunications and financial services.

IEEE 1588v2 operates over Ethernet and can synchronize clocks to within sub-microsecond accuracy in standard network conditions, and with optimized networks, it can indeed reach nanosecond-level precision. This makes it a critical protocol for environments where timing and coordination between devices must be extremely precise.

In contrast, other options listed provide less precise time synchronization. IEEE 802.1Q is primarily a standard for VLAN tagging, Simple Network Time Protocol (SNTP) and Network Time Protocol (NTP) are both designed for general time synchronization on computer networks, but their accuracy typically reaches milliseconds rather than the nanosecond range.