System Management
284
7210 SAS-M, T, R6, R12, Mxp, Sx, S Basic System
Configuration Guide
3HE 16132 AAAB TQZZA Edition: 01
When a 7210 SAS receives Announce messages from one or more configured peers
or multicast neighbors, it executes a Best Master Clock Algorithm (BMCA) to
determine the state of communication between itself and the peers. The system uses
the BMCA to create a hierarchical topology, allowing the flow of synchronization
information from the best source (the grandmaster clock) out through the network to
all boundary and slave clocks. Each profile has a dedicated BMCA.
If the profile setting for the clock is ieee1588-2008, the precedence order for the best
master selection algorithm is as follows:
•priority1
• clock class
• clock accuracy
• PTP variance (offsetScaledLogVariance)
•priority2
• clock identity
• steps removed from the grandmaster
The 7210 SAS sets its local parameters as described in Table 35.
If the profile setting for the clock is itu-telecom-freq (ITU G.8265.1 profile), the
precedence order for the best master selection algorithm is:
• clock class
• PTSF (Packet Timing Signal Fail) - Announce Loss (miss 3 Announce
messages or do not get an Announce message for 6 seconds)
•priority
The 7210 SAS sets its local parameters as described in Table 36.
Table 35 Local Clock Parameters When Profile is Set to ieee1588-2008
Parameter Value
clockClass 248 – the 7210 SAS is configured as a boundary clock
255 – the 7210 SAS is configured as an ordinary clock slave
clockAccuracy FE - unknown
offsetScaledLogVariance FFFF – not computed
clockIdentity Chassis MAC address following the guidelines of section
7.5.2.2.2 of IEEE 1588-2008
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