GE DR60 Technical Manual page 49

DR60
5.5.2 PTP Configuration
49
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IRIGB: sets the DR60 to be synchronized with IRIGB. No further configuration is
necessary.
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PTP: sets the DR60 to be synchronized with PTPv2. The PTP configuration presents
the following parameters:
The PTPv2 synchronization source presents the following parameters:
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Holdover Time: Period during which the DR60 can maintain the
synchronization quality without an external sync reference, thanks to drift of
the internal clock. Range: 5 – 60s.
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Network Interface: Choses the Ethernet port used for the PTP sync.
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Profile: Choses between the PTP profiles: Power IEEE C37.238/2011, P2P
default and Custom.
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Domain Number: A PTP domain is a collection of one or more PTP subdomains.
A subdomain is a logical grouping of 1588 clocks that synchronize to each
other using the PTP protocol, but that are not necessarily synchronized to PTP
clocks in another PTP subdomain. Subdomains provide a way of implementing
disjoint sets of clocks, sharing a common network, but maintaining
independent synchronization within each set. The domain number can be set
as 0, 1, 2 or 3.
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Network Protocol: allows the user to choose between the UDP protocol and
Ethernet layer 2.
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VLAN ID and Priority: Define VLAN parameters according to IEEE 802.1Q.
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Operation Mode: Two options are available:
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Two-step: In two-step-mode the master sends a synchronization
message – SYNC message – with an estimated value of the time
cyclically to the connected slaves. Parallel to this, the time at which
the message leaves the sender is measured as precisely as possible.
The master then sends this actual exact transmission time of the
corresponding sync message to the slaves in a second message -
follow-up message. These also measure the reception time of these
messages as exactly as possible and can correct the correction
value (offset) to the master from it. The slave clock is then
corrected by this offset. If the transmission line were to have no
delay, both clocks would be synchronized.
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One-step: The master sends a synchronization message – SYNC –
message with the precise value of the time cyclically to the
connected slave. Other than in two-step-mode, the precise time is
inserted into the SYNC message "on-the-fly" by the hardware. No
FOLLOWUP – messages are needed in this mode. The calculation of
the offset is the same as in two-step-mode..
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Delay Mechanism: Two delay mechanism are defined:
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End-to-end: Only measures the time taken for a PTP event message
to transit the bridge and provide this information to the receiving
DR60-TM-EN-2A