Accurate Frequency Synchronization

C.

The Timing over Packet solutions provide a mechanism to transfer frequency, time, and phase information over packet networks. This information is essential for applications such as mobile networks, broadcasting, and financial services.

Out of the given options, the Timing over Packet Solution that provides only accurate frequency synchronization but does not provide time/phase synchronization is the "Synchronous Ethernet."

Synchronous Ethernet is an ITU-T standard that allows the distribution of clock signals over Ethernet networks. It is a cost-effective solution for frequency synchronization because it does not require specialized equipment like other timing solutions such as GPS or atomic clocks.

Synchronous Ethernet works by transmitting clock signals through the Ethernet PHY layer. The clock signals are embedded in the Ethernet frames' preamble, which is a 7-octet field that precedes the Ethernet frame. The clock signal is sent through the network to the receiving equipment, which extracts the clock signal from the Ethernet frames' preamble and uses it to synchronize its clock.

Synchronous Ethernet provides accurate frequency synchronization but does not provide time or phase synchronization. This means that the clock signal's frequency is accurate, but there may be variations in the clock signal's time and phase. In other words, Synchronous Ethernet cannot guarantee that two clocks will have the same time or phase, but they will have the same frequency.

In contrast, the other options in the question, such as Network Time Protocol (NTP), Precision Time Protocol (PTP), and Transfer of Clock BOF, provide both accurate frequency and time/phase synchronization.

NTP is a protocol used to synchronize clocks over a network. It provides both frequency and time synchronization by exchanging time information between servers and clients.

PTP is a more precise timing protocol that can achieve sub-microsecond accuracy. It provides both frequency and time/phase synchronization and is often used in applications that require high precision, such as financial trading systems.

Transfer of Clock BOF is a Cisco proprietary technology that provides both frequency and time/phase synchronization by transferring clock signals over an IP network.

In conclusion, Synchronous Ethernet provides accurate frequency synchronization but does not provide time/phase synchronization, while NTP, PTP, and Transfer of Clock BOF provide both frequency and time/phase synchronization.