Symmetricom TimeProvider 500, User Manual

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098-00172-000 Revision A – December, 2009 TimeProvider 500 2.0 User’s Guide 65
Chapter 3 Operations
Flow State

Operational Min TDEV – an operational stability estimate using the minimum
TDEV metric defined in G.8261. Smaller values correlate to better output
performance.

Operational MAFE – an operational stability estimate proposed to the ITU-T.
MAFE (Maximum Average Frequency Error) estimates the maximum frequency
error of a packet clock based on a clustering and averaging window. The
clustering window is 1 minute and the averaging window is 15 minutes.

Min Cluster Width – the current operational minimum cluster width used in the
forward clock estimate.

Mode Width – the current estimate of the main mode of the forward packet delay
variation. The mode width is used in both weighting and compensation. Mode
width is a good indicator of loading.

Flow State – displays the flow state of the GrandMaster clocks (GM1/GM2)

Clock id – displays the Clock ID of the grandmaster(s) that has flow with the
TimeProvider 500.

Output TDEV Estimate – uses the reference clock model being developed in
ITU-T SG13 to provide an operational estimate of the output performance of the
TimeProvider 500 in terms of peak TDEV stability.
Flow State
If there is an established flow, the clock ID of that master clock is shown (it can be
directly recovered from any PTP packet sent by that master). In the example shown,
there is no GM2 flow, so its clock ID is zeroed.
Table 3-1 and Figure 3-7 shows the
possible values for the flow state. In the previous example, GM2 remains in the
initializing state because there is no actual grandmaster clock at its assigned
address.
Table 3-1. Possible Flow State
Flow State Description
Initializing Communication with grandmaster clock is being established.
Waiting for GM to
respond to signaling TimeProvider 500 is waiting for a lease request response from the
grandmaster clock.
Checking Announce
messages TimeProvider 500 is waiting for an Announce message to be qualified.
Checking for SYNC
messages TimeProvider 500 is waiting on SYNC messages per the flow request
agreement.
Checking for Delay
messages TimeProvider 500 is waiting on Delay messages per the flow request
agreement.