EXFO FTB-800 Series for FTB-1 - Manual (Page 109)

Test Setup - Test Configurator, Timer, and System
NetBlazer 99
1588 PTP
PTSF Alarm Timeout/Threshold
Note: The following parameters are also used to declared the Pass/Fail verdict.

Receipt Timeout defines the threshold used to declare a Loss
Announce or Loss Sync message alarm: 2 to 255 messages (default is
3 messages). A message is considered lost if not received within its
expected arrival time and a loss alarm is declared when the number of
consecutive lost messages is greater than or equal to the defined
Receipt Timeout.

IPDV Threshold defines the inter packet delay variation threshold
used to raise the Unusable message alarm. The alarm is raised when
IPDV is not within the configured IPDV Threshold: 0.001 to 1000ms
(default is 2ms). The minimum value of 0.001 is adjusted when the
Sync or Delay Req is set to 4 messages/s or less.
Quality Level
The quality level characterizes the clock quality in terms of network
synchronization.

QL Mismatch Monitoring when selected (default) enables the Quality
Level mismatch monitoring.

Expected QL allows, when QL Mismatch Monitoring check box is
selected, the selection of the Expected Quality Level value: QL-PRS by
default. Refer to page 319 for more information.