IEEE PTP Profile for Power Systems Applications (C37.238-2011)

Feature/ ParameterNoteRangeDefault ValueC37.238-2011 Clause
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Profile Identification

profileName:IEEE Standard Profile for Use of IEEE 1588 Precision Time Protocol in Power System Applications


5.1
profileVersion:1.0


profileIdentifier:  1C-12-9D-00-00-00


Specified by:IEEE 1588 Profile for Power System Applications Working Group of the IEEE Power System Relaying Committee and IEEE Power System Substation Committee.  


Location:http://standards.ieee.org


PTP Options

Permitted NodesOrdinary clocks, peer-to-peer transparent clocks, boundary clocks



Prohibited Nodes




Transport MechanismsIEEE 802.3 Ethernet, as per IEEE1588-2008 Annex F (PTP directly over Ethernet).
VLAN tags (IEEE802.1Q) are mandatory, with a default priority of 4, and default VLAN ID of 0.
Other transport mechanisms are prohibited.



5.6
Multicast or UnicastFull multicast operation, using MAC addresses specified in IEEE1588-2008 Annex F:
- Uses MAC address 01-80-C2-00-00-0E for Pdelay messages
- Uses MAC address 01-1B-19-00-00-00 for other messages



5.8
BMCAUses default BMCA specified in clauses 9.3.2, 9.3.3 and 9.3.4 of IEEE1588-2008


5.4.1
Path Delay MeasurementPeer Delay mechanism


5.3
PTP ManagementManagement specified by way of a SNMP MIB
- Grandmaster support for SNMP MIB is mandatory
- SNMP support for other devices is optional
- Ordinary clocks not supporting SNMP must provide the following information: TimeInaccuracy, traceability, offset from GM, alarm if offset from GM reaches a configurable limit.



5.5
Message TypesUsed: Announce, Sync, Follow-up, Pdelay_Req, Pdelay_Resp, Pdelay_Resp_Follow_Up
Not used: Delay_Req, Delay_Resp, Signalling, Management




One-step and Two-step clockOne-step operation is recommended, although two-step operation is allowed.
All ingress ports must support both one-step and two-step clocks.
All egress ports may support either one-step or two-step clocks.



5.7.1
One-way and Two-way OperationOne-way Sync message operation due to use of peer delay messages.
Two-way operation for peer delay messages.




Clock identityThe ALTERNATE_TIME_OFFSET_INDICATOR TLV must be supported by all devices.


5.11
SecurityAnnex K security not used.
Other security measures not mentioned.



5.10
Unicast negotiation
(IEEE1588-2008 clause 16.1)
Not used.


5.10
Path trace
(IEEE1588-2008 clause 16.2)
Not used.


5.10
Alternate timescales
(IEEE1588-2008 clause 16.3)
The ALTERNATE_TIME_OFFSET_INDICATOR TLV must be supported by all devices.


5.12.1
Grandmaster clusters
(IEEE1588-2008 clause 17.3)
Not used.


5.10
Alternate masters
(IEEE1588-2008 clause 17.4)
Not used.


5.10
Unicast discovery
(IEEE1588-2008 clause 17.5)
Not used.


5.10
Acceptable master table
(IEEE1588-2008 clause 17.6)
Not used.


5.10
Cumulative frequency scale factor offset
(IEEE1588-2008 Annex L)
Not used.


5.10

PTP Attribute Values

(all others as per PTP, defined in IEEE1588-2008)

Default data set

domainNumberAll clock types012705.2
clockQuality.clockClassGrandmaster clocks6, 7, 187
5.9
clockQuality.clockAccuracy
Not specified
clockQuality. offsetScaledLogVariance
Not specified
priority1Grandmaster-capable clocks1281285.2
Slave-only clocks2552555.2
priority2Grandmaster-capable clocks1281285.2
Slave-only clocks2552555.2
slaveOnlyGrandmaster-capable clocksFALSEFALSE5.2
Slave-only clocksTRUETRUE5.2

Port data set

logAnnounceIntervalAnnounce message rate: 1 message/second005.2
announceReceiptTimeoutPreferred Grandmaster clocks: 2 missing messages225.2
Grandmaster-capable clocks: 3 missing messages335.2
logSyncIntervalSync message rate: 1 message/second005.2
logMinPdelayReqIntervalPdelay_req message rate: 1 message/second005.2

Transparent clock default data set

primaryDomain
012705.2

IEEE_C37_238 TLV

Grandmaster IDUser configurable0x00050x00FE
5.12.2
GrandmasterTimeInaccuracyShould be better than 0.2us0x000000000xFFFFFFFF
Annex B
NetworkTimeInaccuracyShould be better than 50ns per transparent clock0x000000000xFFFFFFFF






Best Master Clock Algorithm (BMCA)

BMCA type:Default BMCA


5.4
State decision algorithmDefault state decision algorithm


Data set comparison algorithmDefault data set comparison algorithm


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