Calrec Argo S Startup Manual page 31

Synchronisation - AoIP Devices
This page is accessed from the Devices
menu when an external AoIP device's
'Sync' tab is selected and appears as
shown above right for 'Combo 21.
It provides the ability to synchronise
the network clocks of the devices.
The network clocks are carried in the
ethernet data packets to/from the device
and as such do not require separate
synchronisation inputs. This page is used
to select PTP clocks and the response of
the AoIP interfaces on the devices.
The sync page is split into 2 areas:-
The right hand area shows the Port Status
of the AoIP device interface primary
and secondary ports with respect to the
master clock. The columns in this Port
Status table provide information about:-
- Port status indicators, Green is active,
Red is not active.
- Primary and Secondary port identifiers
for each device i.e. 1A & 1B.
- Port statuses:- MASTER provides
a clock source for it's downstream
connections, SLAVE follows the clock
source that is in the Master state or it is
defined as FAULTY or passive which is
neither the master or a slave of a master,
or when no connection has been made.
- Offset (from Master):- This is a measure
of how accurately a slave synchronises
with a master clock.
- Mean Path Delay is the average time
taken for PTP frames to travel between
master and slave, a large mean path
delay is indicative of jitter and latency.
The left hand area displays the PTP
Grandmaster ID of the current clock
source. The settings to the right of this
allow the user to modify how the interface
will interact with the clock.
There are basic configuration settings and
advanced configuration settings which are
accessed from the 'Advanced settings'
button in the footer of the page.
Basic Synchronisation Settings
As shown above and below right:-
Domain: Multiple PTP clocks can exist
on the same network these are kept
separate by placing them in different
domains. The domain number (0-255)
selects the domain to be used.
BASIC AOIP DEVICE SYNCHRONISATION
ADVANCED AOIP DEVICE SYNCHRONISATION
Priority: This value (0-255) is used in the
Best Master Clock Algorithm to determine
which AES67 device will become the PTP
Grand Master Clock in that domain.
Slave Only: This tick box is used to
prevent a device from establishing itself
as a Master and should be selected when
locking to an external PTP clock.
Advanced Synchronisation Settings
As shown below right:-
Priority 1: Same as basic Priority setting.
Priority 2: Backup Priority setting.
Modes: These transparent clock modes
calculate the required time it takes to
send traffic either from E2E (end to end)
or from P2P (peer to peer) and updates
the PTP time correction field as required.
Two Step: This improves the flexibility
of the synchronisation system by first
sending the sync message followed by a
separate time stamp.
Sync Interval: Time period between sync
messages which can vary from -7 to +1.
Announce Interval: Time period between
PTP announcement messages which can
vary from -3 to +4.
Announce Receipt Timeout: Number
of PTP intervals a device can miss before
timing out which can vary from 2 to 10.
Delay Request Interval: Time period
between PTP delay request messages
which can vary from -1 to +6.
Note:- In the images above the
Secondary AoIP port is not connected.
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