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https://www.ipinfusion.com/documentation/application-notes/


Why it's important

Slip in phase and frequency is detrimental to normal operation in mobile TDD
(Time Division Duplex) band causing inter-cell interference and eventually effecting call degradation
and hand-off coordination
PtP

PTP leverages hardware time stamping of PTP PDUs to achieve
sub-100 nanosecond level accuracy while
filtering dynamic time error accumulation along the way

ptp vision

PTP (Precision Time Protocol) - IEEE 1588-2002

PTPv2 (Precision Time Protocol Version 2) - IEEE 1588-2008

Key Differences

  • Accuracy: PTPv2 generally provides higher accuracy and precision than the original PTP.
  • Features and Flexibility: PTPv2 includes features like boundary and transparent clocks, the Best Master Clock Algorithm, and support for profiles, which are not present in the original PTP.
  • Use Cases: While both versions are used in industrial, scientific, and commercial applications, PTPv2 is better suited for environments requiring higher precision and more complex network topologies.
The version 2 of IEEE 1588-2008

 introduces the concept of “profile”
G.8265.1

ITU-T G.8265.1 telecom profile is specified for frequency synchronization

>>> G.8275.1 Full Timing Support (FTS) 

G.8265.2

ITU-T G.8275.1/G.8275.2 are for phase/time synchronization

>>> G.8275.2 Partial timing support (PTS)

>>> G.8275.2 Assisted Partial timing support (APTS)

>>> E2E Transparent Clock , PTP Master

Diagram

Image Modified

SyncE config


Code Block
titleSyncE Config
show running-config synce
!
synce
 synchronization option 1
clock-selection
mode ql-disabled 
!
interface ce3
 synce
  mode synchronous
  input-source 20
  output-source
  wait-to-restore 1
!
interface ce1
 synce
  mode synchronous
  input-source 30
  output-source
  wait-to-restore 1
!
interface ce44
 synce
  mode synchronous
  input-source 10
  wait-to-restore 1


Quality Level

QL_SSU_A (Synchronization Supply Unit Type A)

QL_PRC (Primary Reference Clock)

QL_DNU (Do Not Use)

ESMC (Ethernet Synchronization Messaging Channel)

Using QLhttps://docs.ipinfusion.com/service-provider/index.html#page/OcNOS-SP/SyncE-Config/Config_SynchE.html#ww506644
Using priority

https://docs.ipinfusion.com/service-provider/index.html#page/OcNOS-SP/SyncE-Config/Config_SynchE.html#ww504919

!!! clock-selection mode ql-disabled   >>> will work on priority

and not use ESMC meaages 



PtP config Attached to GM clock on ce44


Code Block
titleSyncE Config
collapsetrue
show runn ptp
!
ptp clock 0 profile g8275.1
 number-ports 5
 system-clock-sync 30
 clock-port 1
  network-interface ce44
  exit
 clock-port 2
  master-only
  network-interface ce1
  exit
 clock-port 4
  master-only
  network-interface ce3
  exit




uk-wnlb-lg-pol-cin-01(config-clk-port)#2024 Jul 19 11:03:11.566 : uk-wnlb-lg-pol-cin-01 : HSL : CRITI : [PTP_SERVO_STATE_2]: Phase Locked. -> Holdover in Spec.


Code Block
titleshow ptp servo
uk-wnlb-lg-pol-cin-01#show ptp servo
PTP servo status for clock 0
  Servo Config                : Freq + Phase Correction
  Servo State                 : Holdover-in-spec
  Servo State Duration        : 00:03:51
  Servo APTS Mode             : N/A
  Frequency Correction        : 0.000 ppb
  Phase Correction            : 977250000.000 nsec
  Offset From Master          : 0 nsec
  Mean Path Delay             : 13 nsec
  APTS GPS to PTP Offset      : N/A
  Sync Packet Rate            : 16
  Delay Packet Rate           : 16




Code Block
titleshow ptp clock 0