Alcatel-Lucent 7210 SAS M Configuration Manual page 231

System Management
two-step synchronization operation can be used, with the two-step operation requiring a follow-up
message after each synchronization message.
NOTE: The 7210 SAS-M and 7210 SAS-X supports only two-step operation. 7210 SAS-T
supports one-step operation by default and can interoperate with devices supporting two-step
operation.
During startup, the PTP slave clock receives the synchronization messages from the PTP master
clock before a network delay calculation is made. Prior to any delay calculation, the delay is
assumed to be zero. A drift compensation is activated after a number of synchronization message
intervals occur. The expected interval between the reception of synchronization messages is user-
configurable.
The basic synchronization timing computation between the PTP slave clock and PTP best master
is illustrated in Figure 18. This figure illustrates the offset of the slave clock referenced to the best
master signal during startup.
7210 SAS M, T, X, R6 Basic System Configuration Guide Page 231