Excerpt from Automotive specification: syncReceiptTimeout [gPTP 10.6.3.1] behavior for non GM AED-B devices is modified as follows: a) AED-B Sync processing during loss of Sync: During normal operation, the AED-B will receive and process Sync messages on its slave port. If the AED-B detects a termination of these Sync messages on its slave port, the AED-B shall continue sending Sync messages out of its Master Ports using the most recent valid record received on the slave port as its basis. The AED-B shall use the preciseOriginTimestamp from the most recent valid record received from the GM in all Follow_Up messages it sends, and it shall advance the correctionField in all Sync and Follow_Up messages it sends, to reflect the time that has passed since receipt of the most recent valid record. The AED-B shall use its local time base and any known cumulativeScaledRateOffset to make the calculations for these messages. b) AED-B Sync recovery: If the AED-B receives a valid Sync message on its slave port then it shall update that record and resume normal Sync operation. The Bridge is not required to avoid, mitigate or report a phase jump in this circumstance. c) AED-B Sync Absence: On startup if an AED-B does not receive a Sync message on a slave port within a configurable time, then it shall use a default time record and begin sending Sync messages with constant preciseOriginTimestamp and advancing correction on its Master role ports. The time to wait for an initial Sync message is user configurable, but shall never be greater than 20 seconds.
1. How can the above-described behavior of AED-B (bridge device) be implemented using linuxptp? 2. Is the algorithm in question applicable to the 802.1 AS profile? Apparently, 802.1 AS provides a similar mixed mode of operation - TRANSPARENT (when there is no sync receive timeout) and actually BOUNDARY (in Sync timeout state). _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
