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IEEE 802.3cx improves the timing performance and timestamp accuracy of Ethernet interfaces, including considerations for the following aspects:
Data delay measurement point, DDMP (i.e. the message timestamping point)
Idle, Alignment Marker (AM), and Code Word Marker (CWM) insertion and removalData delay measurement point, DDMP (i.e. the message timestamping point)
PCS lane distribution and merging
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