IEEE 1588 Analysis
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9.2.4. Delay Statistics
The Delay statistics panel is probably one of the most important PTP results panel
available in PTP clock emulation mode as it contains valuable quantitative information
to assess the performance of the transmission network. Like it happens with most of
the PTP results, the Delay statistics are available only for Port A.
Delay statistics do not depend on the operation mode (IP endpoint or Ethernet
endpoint) but they do on the clock role. For example, in master emulation mode, Sync
messages are ignored and therefore all metrics related with this message are not
available. The PTP delay statistics are compensated with the help of the correction field
included in PTP event messages. The objective of the delay compensation is to
evaluate the transmission performance achieved with switches behaving as
transparent clocks. It is important to note that if the equipment is configured in slave
emulation mode, some delay statistics may not be accurate. The reason is that in this
mode the time reference is generated based on received PTP messages, which are at
the same time the objects to be evaluated. One of the most visible effects is that any
steady state long term estimation of the path asymmetry is zero. An alternative to
improve the accuracy of the delay statistics is to use an external time reference (GNSS)
and configure PTP mode to Test (pseudo-slave).
Management Number of received (RX) and transmitted (TX) Management
messages.
Management messages are used to connect the PTP enti-
ties to the management system and enable operation and
maintenance of the synchronization network.
Domain mismatch Total count of received IEEE 1588 messages no correspond-
ing to the currently configured PTP domain.
Sync seq. anomaly This is a counter increased in one unit for each out-of-order
received Sync message. An out-of-order message contains
a sequence number different to the expected value.
Table 9.6: IEEE 1588 Message Statistics
Result Description
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