IEEE "Telecom Profile 2008"

Latest document version:IEEE1588-2008, Annex A.9

Frequency distribution to better than 16ppb 

Feature/ ParameterNoteRangeDefault ValueIEEE1588-2008 Clause

Profile Identification

profileName:Recommendation for implementations in unicast networks or networks with
non-PTP bridges and routers.
This is an informal but often implemented profile, based on the "default" profile in Annex J.3.

Annex A.9

Annex J.3.1
profileIdentifier:  00-1B-19-00-01-00

Annex J.3.1
Specified by:Precise Networked Clock Synchronization Working Group of the IM/ST Committee of the IEEE

Annex J.3.1

Annex J.3.1

PTP Options

Permitted NodesOrdinary clocks (i.e. Grandmasters, slave-only clocks), boundary clocks, transparent clocks

Annex A.9.1
Prohibited NodesNone

Transport MechanismsNot specified. Any valid unicast transport mechanism may be used,
e.g. as specified in Annexes D to I of IEEE1588

Annexes D to I
Multicast or UnicastAll messages are sent in unicast.
Unicast negotiation is used by default, but a management procedure could be used.

Annex A.9.3, A.9.4.2
BMCADefault BMCA, as specified in clause 9.3.2.

Annex A.9.4.1, J.3.3
Path Delay MeasurementUses delay_request/response mechanism by default.
Peer delay mechanism is optional.

Annex A.9.4.2,
PTP ManagementOptional.

Annex A.9.4.1
Clock IdentityStandard PTP behaviour
Message TypesUsed: Announce, Sync, Follow-up, Delay_Req, Delay_Resp, Signaling
Not used: Pdelay_Req, Pdelay_Resp, Pdelay_Resp_Follow_Up
The use of Management messages is permitted.

Annex A.9.4.2
One-step and Two-step clockStandard PTP behaviour.

One-way and Two-way OperationStandard PTP behaviour.

SecurityNot mentioned.

Unicast negotiation
(IEEE1588-2008 clause 16.1)
Used by default.

Annex A.9.4.2
Path trace
(IEEE1588-2008 clause 16.2)

Annex A.9.3
Alternate timescales
(IEEE1588-2008 clause 16.3)
Not mentioned.

Grandmaster clusters
(IEEE1588-2008 clause 17.3)
Permitted, inactive by default

Annex J.3.3
Alternate masters
(IEEE1588-2008 clause 17.4)
Permitted, inactive by default

Annex J.3.3
Unicast discovery
(IEEE1588-2008 clause 17.5)
Used by default.

Annex A.9.4.2
Acceptable master table
(IEEE1588-2008 clause 17.6)
Permitted, inactive by default

Annex J.3.3
Cumulative frequency scale factor offset
(IEEE1588-2008 Annex L)
Not mentioned.

Message Rates

Sync & Follow-up1 every 2 seconds to 128 per second, default 16 per second1/212816A.9.4.2
Delay_request/response1 every 64 seconds to 128 per second, default 16 per second1/6412816
Announce1 every 8 seconds to 8 per second; default 1 every 2 seconds1/881/2
Peer Delay_request/responseNone (uses Delay_request/response mechanism)

SignalingAs required for unicast negotiation


PTP Configurable Attribute Values

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

Default data set

twoStepFlagStandard PTP behaviour.

clockIdentityStandard PTP behaviour.

numberPortsStandard PTP behaviour.

clockQuality.clockClassStandard PTP behaviour.

clockQuality.clockAccuracyStandard PTP behaviour.

clockQuality. offsetScaledLogVarianceStandard PTP behaviour.

priority1Default value 128.0255128Annex J.3.2
priority2Default value 128.0255128Annex J.3.2
domainNumberDefault value 0.01270Annex J.3.2
slaveOnlyDefault value FALSE (if configurable).FALSETRUEFALSEAnnex J.3.2

Port data set

portIdentity.clockIdentityStandard PTP behaviour.

portIdentity.portNumberStandard PTP behaviour.

logMinDelayReqIntervalNot used (covered by unicast negotiation - see details below)

logAnnounceIntervalNot used (covered by unicast negotiation - see details below)

announceReceiptTimeoutTimeout period before declaring loss of announce service (in number of missing messages)2103Annex J.3.2
logSyncIntervalNot used (covered by unicast negotiation - see details below)

delayMechanismDefault mechanism is E2E (0x01)

0x01Annex J.3.3
logMinPdelayReqIntervalNot used in this profile.

versionNumberAlways set to 2


PTP common message header flags

alternateMasterFlagStandard PTP behaviour.

twoStepFlagStandard PTP behaviour.

unicastFlagStandard PTP behaviour.

PTP profile Specific1Standard PTP behaviour.

PTP profile Specific2Standard PTP behaviour.

ReservedStandard PTP behaviour.

leap61Standard PTP behaviour.

leap59Standard PTP behaviour.

currentUTCOffsetValidStandard PTP behaviour.

ptpTimescaleStandard PTP behaviour.

timeTraceableStandard PTP behaviour.

frequencyTraceableStandard PTP behaviour.

controlFieldStandard PTP behaviour.

Multicast and Unicast Operation

Full multicast operationPermitted, but must be inactive by default.

Annex A.9.1, A.9.4.2
Full unicast operationAll messages are sent in unicast.

Hybrid unicast/multicastNot required by this profile.

Unicast negotiation processBoth masters and slaves should support unicast negotiation (IEEE1588-2008 Clause 16.1).

Annex A.9.3, A.9.4.2
duration fieldDuration of unicast service lease101000300Annex A.9.4.2
logInterMessagePeriodSuggested ranges:
Annex A.9.4.2



R (Renewal Invited)Standard PTP behaviour.FALSETRUEFALSE16.

Master Selection Process

BMCA type:Default BMCA

State decision algorithmDefault state decision algorithm

Data set comparison algorithm (master selection process)Default data set comparison algorithm


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