Bridge Technologies VB440 - Page 56

- Announce Interval (-3 to +1)
- Annonse Receipt Timeout (2-255)
Note that if Mode  is not configured correctly, “out of mode” will appear as a warning
underneath PTP clocks  . An example might be that L2 Multicast has been selected
instead of IP multicast traffic. The Domain number on the VB440 needs to be the
same as the clock it's going to synchronize to.
Priority1 indicates the VB440s own internal Priority1. Please note that this means the
VB440 will never synchronize to a clock with a higher value in the Priority1  field
(Lower priority) than its own.
The table below shows the ‘Logarithm to the base 2’ mapping between the
configured values, packets per second and seconds between packets.
Sync interval  indicates how often VB440 synchronizes to the master clock. The
Announce Interval  specifies how often master clocks should announce themselves,
whereas Announce Receipt Timeout  specifies the number of announce intervals that
can pass before the selected master clock is considered lost if no announce packets
received.
‘Best Master Clock Algorithm’ (BMCA) performs a selection between the available
clocks to ensure that the best suitable clock is acting as master at all times. The
algorithm compare the clocks in the following order:
a) Priority 1 (0-255)
Log2
Packets per second
Seconds between packets
-7
128
0.008
-6
64
0.016
-5
32
0.031
-4
16
0.063
-3
8
0.125
-2
4
0.250
-1
2
0.500
0
1
1.000
1
0.5
2.000
56 VB440 Studio Probe User’s Manual v6.0 © Bridge Technologies Co AS