Setting Date and Time Automatically using PTP
  • 07 Aug 2024
  • 9 Minutes to read
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Setting Date and Time Automatically using PTP

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Article summary

Precision Time Protocol (PTP), offers an advanced method of synchronisation in Ethernet networks. Users can enable this synchronisation to achieve maximum scalability in the network infrastructure.

PTP boundary clock enables users to configure a clock with multiple PTP ports in a domain and maintains the timescale used in the domain. It can serve as the main source of time, for example, the master clock and can also synchronise to another clock, such as a slave clock.


Note: PTP Boundary Clock is only available on LX-SyncE only.

To update the date and time automatically using PTP

  1. Access the page System ▶Configuration ▶Time ▶PTP ▶Configuration

PTP Settings

ParameterDescription
Clock EnableEnables the PTP Precision Time Protocol clock synchronisation module.
Inbound criterionMax threshold for synchronisation to declare synchronisation state. Available options are 1 microsecond, 100 microseconds or class-b

Note: The class-b option is available only for platforms (e.g: LX-SyncE) that support Class-B compliant (See ITU-T G.8273.2)

Inbound statusCurrent state of the synchronisation error. (Expressed in nanoseconds)
Synchronisation statusThe status of the synchronisation.

Clock parameters

ParameterDescription
ClassAn attribute defining a clock’s TAI traceability

Acceptable values range from 0 to 254.

Prio 1A user configurable designation, where the clock belongs to an ordered set of clocks from which a master is selected.

Acceptable values range from 0 to 255

Prio 2A user configurable designation, which provides finer grained ordering among otherwise equivalent clocks.

Acceptable values range from 0 to 255

PTP ProfileDefault PTP profiles set by the administrator.

PTP (IEEE1588-2008) introduced Profile, permitting a liberty on prerequisites, parameters, and algorithm to handle the synchronisation.

Supported profiles:

  • PTP Default Profile: Precision time protocol telecom profile for frequency and phase/time synchronisation, which supports L2 Multicast with Slave mode only.
  • PTP Telecom Profile (ITU-T G.8265.1): Precision time protocol telecom profile for frequency synchronisation, which supports L3 Unicast with Slave Mode only. This Telecom Profile is backward compatible with Accedian legacy PTP feature.
  • PTP Telecom Profile (ITU-T G.8275.1): Precision time protocol telecom profile for phase/time synchronisation with full timing support from the network. Supports L2 Multicast for both Ordinary Clock (Master Clock, Slave Clock) and Boundary Clock with Class-B compliant.
Layer-2 PTP port listList of PTP ports for Default profile and PTP Telelcom ITU-T G.8275.1 profile.
Layer-3 PTP port listList of PTP ports for PTP Telelcom ITU-T G.8265.1 profile.

Configuring PTP Port Settings
To create a new PTP port for the selected profile

  1. Access the page System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Click Add under the Layer-2 or Layer-3 PTP port list.

  3. Click Apply.

To delete a PTP port for the selected profile

  1. Access the page System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Click on the PTP port.

  3. Click Delete.

To edit a PTP port for the selected profile

  1. Access the page System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Click on the PTP port.

  3. Click Apply.

PTP Settings (System ▶Configuration ▶Time ▶PTP ▶Configuration)

To add a Layer-3 PTP port

  1. From System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Select the Telecome Profile (ITU-T G.8265.1) in the PTP settings dialog.

  3. Click Add , under Layer-3 PTP port list, and the Layer-3PTP port settings dialog will open.

ParameterDescription
PTP port nameName of the PTP port.
Time to LiveThe Time To Live (TTL) is the limit on the number of hops a packet is allowed before it is dropped.

Range: 1-255

Priority Settings

ParameterDescription
DiffServ Code PointWhen using PTP, the priority can be set in the Differentiated Services Code Point by making a selection in the drop-down list.

Range: 0-63.

When using PTP, the priority of the VLAN frames can be set in the VLAN priority bits if the link is through a VLAN.

Range: 0-7

Message Frequencies

ParameterDescription
Sync IntervalSpecifies the interval of Sync messages.

Possible values are:

  • -4: 16 messages/ second
  • -3: 8 messages/ second
  • -2: 4 messages/second
  • -1: 2 messages/second
  • 0: 1 message/second
  • 1: 1 message/2 seconds
  • 2: 1 message/4 seconds
  • 3: 1 message/8 seconds
Announce IntervalSpecifies the interval of Announce messages.

Possible values are:

  • -3: 8 messages/ second
  • -2: 4 messages/ second
  • -1: 2 messages/second
  • 0: 1 message/second
  • 1: 1 message/2 seconds
  • 2: 1 message/4 seconds
  • 3: 1 message/8 seconds
Default value: 1: 1 message/2 seconds
Announce Receipt TimeoutSpecifies the number of Announce messages that can be lost before a timeout occurs. Range 2-10

Unicast configuration

ParameterDescription
Unicast Renew IntervalInterval between request of Announce/Sync/Delay Response interval; expressed in seconds Acceptable values range from 60 to 1000.
Port modeThe PTP port mode. Specifies the state of PTP port.

Possible values:

  • Force-master: Forced to Master state.
  • Force-slave: Forced to Slave state.
  • Auto: The state of PTP port is determined by the Best Master Clock Algorithm.

Telecom Slave Configuration

ParameterDescription
Sync Receipt TimeoutSpecifies the number of Sync messages that can be lost before a timeout occurs. Range 2-10.
Delay Response Receipt TimeoutSpecifies the number of Delay Response messages that can be lost before a timeout occurs. Range 2-10.

To add a Layer-2 PTP port

  1. From System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Select the Default profile (IEEE1588-2008) or the Telecome profile (ITU-T G.8275.1) in the PTP settings dialog.

  3. Click Add , under Layer-2 PTP port list, and the Layer-2 PTP port settings dialog will open.

ParameterDescription
PTP port nameName of the PTP port.
Interface nameA name to identify the interface. Indicates the interface used to exchange the PTP messages.
Multicast addressThe layer-2 multicast destination address. Both the non-forwardable multicast address 01-80-C2-00-00-0E and the forwardable multicast address 01-1B-19-00-00-00 are supported.
DomainThe domain number.

Range 0-255.

Port modeThe PTP port mode. Specifies the state of PTP port.

Possible values:

  • Force-master: Forced to Master state.
  • Force-slave: Forced to Slave state.
  • Auto: The state of PTP port is determined by the Best Master Clock Algorithm.

Priority Settings

ParameterDescription
Priority Code PointWhen using PTP, the priority of the VLAN frames can be set in the VLAN priority bits if the link is through a VLAN.

Range: 0-7

Message frequencies

ParameterDescription
Sync IntervalSpecifies the interval of Sync messages

Possible values are:

  • -4: 16 messages/ second
  • -3: 8 messages/ second
  • -2: 4 messages/ second
  • -1: 2 messages/ second
  • 0: 1 message/ second
  • 1: 1 message/2 seconds
  • 2: 1 message/4 seconds
  • 3: 1 message/8 seconds
Delay Request OffsetSpecifies delay request offset based on the sync interval.

Range: 0-5.

Announce IntervalSpecifies the interval of Announce messages.

Possible values are:

  • -3: 8 messages/ second
  • -2: 4 messages/ second
  • -1: 2 messages/ second
  • 0: 1 message/ second
  • 1: 1 message/2 seconds
  • 2: 1 message/4 seconds
  • 3: 1 message/8 seconds
Default value: 1: 1 message/2 seconds
Announce Receipt TimeoutNumber of Announce messages not received before a timeout is triggered.

Range 2-10.

Telecome Profile Configuration

ParameterDescription
Default priorityThe localPriority is assigned to a PTP port. This attribute is used when configuring the PTP port in the Telecom Profile ITU-T G.8275.1.

Range: 1-255

Viewing Summary of PTP Port Statistics

To view the summary of PTP port statistics

  1. Access the page System ▶ Configuration ▶ Time ▶ PTP ▶ Statistics .
    A dialog appears with the statistics.

PTP Statistics (System ▶Configuration ▶Time ▶PTP ▶Statistics)

ParameterDescription
IndexIndex assigned to the PTP port.
PTP port nameName of the PTP port.
Last mean path delayThe last known value that PTP frames take to travel between the master and slave.
Last offset adjustmentThe last offset adjustment for the PTP port.
Nbr of synchronisationNumber of PTP port synchronisations.
Nbr of correctionNumber of PTP port corrections

To view PTP port statistics

  1. From System ▶Configuration ▶Time ▶PTP ▶Statistics.
  2. Click on the PTP Port you wish to view, a dialog opens with the PTP port statistics.

PTP Port Statistics (System ▶Configuration ▶Time ▶PTP ▶Statistics)

ParameterDescription
PTP versionThe PTP version number supported on the unit.
Port modeThe PTP port mode.
Port stateThe state of the PTP port.
Clock IDIdentifies the clock
Port IDIdentifies the port

Unicast Negociation Mechanism Message counters

ParameterDescription
T1The last value of T1 timestamp
T2The last value of T2 timestamp
T3The last value of T3 timestamp
T4The last value of T4 timestamp
Last corr. fieldThe last value of correction field
Master IdIdentifies the current master clock
Master addressThe address of the current master clock
ClassPTP clock class of the current master clock. An attribute defining a clock’s TAI traceability

Note: When advertising a new clock class in SyncE and PTP a trap will now be generated and provide the new clock class

Prio 1Priority 1 of the current master clock. A user configurable designation, where the clock belongs to an ordered set of clocks from which a master is selected.
Prio 2Priority 2 of the current master clock. A user configurable designation, which provides finer grained ordering among otherwise equivalent clocks.
AccuracyAccuracy of the current clock
VarianceStability of the current clock
Steps removedNumber of communication paths traversed between the local clock and the grandmaster clock
Time sourceTime source of PTP, it may be internal or a source external to PTP
Grandmaster IdIdentifies the grandmaster

General Message counters

ParameterDescription
AnnounceNumber of Announce messages received or transmitted.
Synccell
Follow-upNumber of Announce messages received or transmitted.
Delay RequestNumber of Follow-up messages received or transmitted.
Delay ResponseNumber of Delay Request messages received or transmitted.
RxRx values for:
  • Announce
  • Follow-up
  • Sync
  • Delay Request
  • Delay Response
TxTx values for:
  • Announce
  • Follow-up
  • Sync
  • Delay Request
  • Delay Response
RequestNumber of Announce, Sync, Delay Response messages requested
GrantNumber of Announce, Sync, Delay Response messages granted
CancelNumber of Announce, Sync, Delay Response messages cancelled
AckCancelNumber of Announce, Sync, Delay Response messages ackCancelled

Configuring the PTP Grantor for the PTP Port

To configure the PTP Grantor

  1. Access the page System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Click on the PTP port you wish to configure from the Layer-3 PTP port list.

  3. Click the Add button below the Unicast PTP Grantor list.

  4. Select the values you wish to configure for the PTP grantor..

  5. Click Apply.

To delete a PTP Grantor instance

  1. Access the page System ▶Configuration ▶Time ▶PTP ▶Configuration.

  2. Select the PTP port in the Layer-3 PTP port list by clicking its name.

  3. Select the PTP grantor instance in the Unicast PTP Grantor list by clicking its name.

  4. Click Delete.


Note: To access the Unicast options, you must select the Telecom Profile (ITU-T G.8265.1) radio button in the PTP Profile settings.
Users can only configure a PTP grantor when working on profile ITU-T G.8265.1.

PTP Grantor configuration for the PTP Port (System ▶Configuration ▶Time ▶PTP ▶
Configuration)

ParameterDescription
PTP Grantor nameName of the PTP grantor.
Interface nameName of the interface used to communicate with the PTP master.
Hostname / AddressName or Address of the PTP master.
DomainThe domain number.

Range: 0-255

PriorityThe priority of PTP master.

Acceptable values: 0 (disabled), 1 (best) and 2 (worst).

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