SyncE Clocking Propagation in Ethernet Links | Cisco Exam 400-201 Answer

SyncE Clocking Propagation

Question

In which way does SyncE propagate the clocking information in a synchronous mode over an Ethernet link?

Answers

Explanations

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A. B. C. D.

C.

https://www.cisco.com/c/en/us/td/docs/optical/cpt/r9_7/cpt972_configuration/cpt972_configuration_chapter_010010.html

SyncE, or Synchronous Ethernet, is a technology used to provide accurate clock synchronization across Ethernet networks. It is particularly important in applications such as telecommunications and mobile networks where precise timing is required for synchronization of network elements and for the delivery of time-sensitive services.

To propagate the clocking information in a synchronous mode over an Ethernet link, SyncE uses dedicated Ethernet frames called Ethernet Synchronous Messaging Channel (ESMC) frames. These frames are sent at regular intervals over the Ethernet link and contain information related to the synchronization of the network.

The ESMC frames are transmitted by the SyncE clock source to all the network elements connected to it, such as switches, routers, and other network devices. The ESMC frames contain information such as the SyncE clock source identity, quality of service parameters, and other relevant information required for synchronization.

In addition to ESMC frames, SyncE also uses the Ethernet frame format to convey clock information. The SyncE clock information is encoded into specific bits of the Ethernet frame preamble, which is a sequence of bytes that precedes the Ethernet frame. The clock information is encoded using a technique called Differential Encoding, which allows the clock information to be propagated along with the Ethernet frame without affecting the integrity of the Ethernet data.

Therefore, the correct answer to the question is C. SyncE uses dedicated ESMC frames that are sent at regular intervals to propagate the clocking information in a synchronous mode over an Ethernet link.