7705
SAR R5.0 Configuration
Note
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SAR |
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P |
Introduction
IEEE 1588-2008 provides a standards-based “timing over packet” distribution technique. It defines the Precision Time Protocol (PTP) for enabling precise synchronization of clocks to a Stratum-1 or Primary Reference Clock (PRC) traceable source. It is used to synchronize frequency, phase, and time of day from a master clock to one or more slaves via UDP/IP multicast or unicast messages. The packet network may or may not be PTP-aware.
Starting in R5.0-R3, a 7705 SAR-M node configured as a 1588v2 Boundary clock or Ordinary Slave clock has the capability to retransmit the PTP Time of Day (ToD) messages received from the 1588 Grand Master (1588 GM) to a base station attached to its dedicated ToD/1PPS port. The base station can then use the received ToD messages for phase alignment to the 1588 Grand master (PRC).
The SAR-M node can also be configured to output a one pulse per second (1PPS) timing signal in conjunction with the transmission of the ToD message. The 1PPS timing signal emits precisely at the top of the second. A typical pulse width is 200ms. The ToD message must be sent at least 1ms after the 1PPS rising edge and end less than 500ms after that rising edge. The 1PPS frequency accuracy can be further improved if the SAR-M node System Sync Unit (SSU) is synced to a more stable frequency source such as “line-timing” or “external-sync” and this can be used to assist the 1588 slave as a stable frequency base.
As of 7705 SAR R5.0-R3, there are two user configurable ToD message formats available, China Telecom format (CT) and China Mobile format (CM).
Setup
Figure 1 - Network setup
Prerequisites
- The SAR-M node that is outputting the 1PPS/ToD signal must be a 1588v2 slave to the 1588 GM. (A 7705 SAR system configured as a 1588v2 Ordinary Master can not be use as the source of ToD messaging as of R5.0-R3.)
- A PTP clock must be enabled and functioning. (See 1588v2 for R4.0 Config Note)
Enable ToD/1PPS on SARM-96
Configuration
The PTP clock must be enabled and locked to the 1588 GM. The node’s SSU does not have to sync or lock to the 1588 GM clock.
- First: Assign the PTP clock(s) to be used as the reference clock for the 1PPS signal and ToD messages. (1PPS is a frequency, ToD is sent in a message datagram)
- Second: Enable the 7705 SAR to output the 1PPS/ToD messages and the message type.
*A:SARM-96# configure system time
*A:SARM-96>config>system>time# ptp
*A:SARM-96>config>system>time>ptp# clock 1 time-ref-priority 1
*A:SARM-96>config>system>time>ptp# back
*A:SARM-96>config>system>time# tod-1pps
*A:SARM-96>system>time>tod-1pps># message-type cm
*A:SARM-96>system>time>tod-1pps># output no shutdown
*A:SARM-96>system>time>tod-1pps># back
*A:SARM-96>config>system>time# info
----------------------------------------------
ptp
clock 1 time-ref-priority 1
exit
ntp
shutdown
exit
sntp
shutdown
exit
zone EDT -04
tod-1pps
message-type cm
output no shutdown
exit
----------------------------------------------
Verification and troubleshooting
- First, verify that the PTP clock is operationally up and locked to the GM:
*A:SARM-96# show system ptp clock 1 detail
===============================================================================
IEEE1588 PTP Clock Information
===============================================================================
-------------------------------------------------------------------------------
Local Clock
-------------------------------------------------------------------------------
Clock Type :
ordinary,slave
Source I/F : ptp1-OStoGM Clock MDA : 1/1
PTP Profile : ieee1588-2008 Dynamic Peers : not allowed
Admin Freq-source : ptp Oper Freq-source : ptp
Clock ID : 38521afffeed053c Clock Class : 255
Clock Accuracy : unknown(254) Clock Variance : not computed
Clock Priority1 : 128 Clock Priority2 : 128
Domain
:
0
Two-Step
: unknown
-------------------------------------------------------------------------------
Parent Clock
-------------------------------------------------------------------------------
Parent Clock ID : 8887868584838281
GM Clock Id : 8887868584838281 GM Clock Class : 6
GM Clock Accuracy : 100ns GM Clock Variance : 25600
GM Clock Priority1 : 128 GM Clock Priority2 : 128
-------------------------------------------------------------------------------
Slave Peer Index : 1 Slave Peer IP : 10.189.2.2
Forward Weight : 100 Reverse Weight : 0
-------------------------------------------------------------------------------
Time Information
-------------------------------------------------------------------------------
Timescale : PTP
Current Time : -
Freq Traceable : true
Time Traceable : true
Time Source : gps
===============================================================================
===============================================================================
Interface Configuration Information
===============================================================================
Source IP Interface : ptp1-OStoGM IP Interface Port : loopback:125
IP Interface Address : 10.10.96.1 PTP Enabled : True
Admin Status : Up Oper Status : Up
===============================================================================
- Second, verify that the 1PPS output port is enabled:
*A:SARM-96# show system time
===============================================================================
Date & Time
===============================================================================
Current Date & Time : 2012/05/17 11:14:25 DST Active : no
Current Zone : EDT Offset from UTC : -4:00
-------------------------------------------------------------------------------
Non-DST Zone :
EDT
Offset from UTC :
-4:00
Zone
type :
non-standard
-------------------------------------------------------------------------------
No DST zone configured.
===============================================================================
Time Of Day - 1 Pulse Per
===============================================================================
Input : shutdown Message Type : cm
Output : no shutdown Source : PTP
Port Type : RS-422
Baud Rate : 9600 Stop Bits : 1
===============================================================================
===============================================================================
When possible, ALU recommends using line timing as the source of frequency reference for 1PPs
- Verify the upstream node (SAR8-97) is locked to a line-timing reference:
*A:SAR8v2-97# show system sync-if-timing
===============================================================================
System Interface Timing Operational Info
===============================================================================
System Status CSM A : Master Locked
Reference Input Mode : Non-revertive
Quality Level Selection : Disabled
Reference Order : external ref1 ref2
Reference Input 1
Admin Status : down
Configured Quality Level : none
Rx Quality Level : unknown
Qualified For Use : No
Not Qualified Due To : disabled
Selected For Use : No
Not Selected Due To : disabled
Reference Input 2
Admin Status : down
Configured Quality Level : none
Rx Quality Level : unknown
Qualified For Use : No
Not Qualified Due To : disabled
Selected For Use : No
Not Selected Due To : disabled
External Reference Input
Admin Status : up
Configured Quality Level : stu
Qualified For Use : Yes
Selected For Use : Yes
Type : 2048Khz-G703
Impedance : 50-Ohm
External Reference Output
Type : 2048Khz-G703
===============================================================================
Starting from release 4.0-R2, Sync-E is automatically enable for all 7705 SAR Sync-E capable Ethernet ports. Therefore, enabling the Sync-E option is not required for the examples used in this CN.
- Configure the SSU on SARM-97 to sync off the Sync-E Ethernet link:
*A:SARM-96# configure system sync-if-timing
*A:SARM-96>config>system>sync-if-timing# begin
*A:SARM-96>config>system>sync-if-timing# ref1 source-port 1/1/1
*A:SARM-96>config>system>sync-if-timing# ref1 no shutdown
*A:SARM-96>config>system>sync-if-timing# commit
*A:SARM-96>config>system>sync-if-timing# info
----------------------------------------------
ref-order external ref1 ref2
ref1
source-port 1/1/1
no shutdown
exit
ref2
shutdown
exit
external
input-interface
shutdown
exit
exit
----------------------------------------------
- Verify the SARM-97 SSU is locked to the Sync-E port:
*A:SARM-96# show system sync-if-timing
===============================================================================
System Interface Timing Operational Info
===============================================================================
System Status CSM A : Master Locked
Reference Input Mode : Non-revertive
Quality Level Selection : Disabled
Reference Order : external ref1 ref2
Reference Input 1
Admin Status : up
Configured Quality Level : none
Rx Quality Level : unknown
Qualified For Use : Yes
Selected For Use : Yes
Reference Input 2
Admin Status : down
Configured Quality Level : none
Rx Quality Level : unknown
Qualified For Use : No
Not Qualified Due To : disabled
Selected For Use : No
Not Selected Due To : disabled
External Reference Input
Admin Status : down
Configured Quality Level : stu
Qualified For Use : No
Not Qualified Due To : disabled
Selected For Use : No
Not Selected Due To : disabled
Type : 2048Khz-G703
Impedance : 50-Ohm
External Reference Output
Type : 2048Khz-G703
===============================================================================
- Configure the SARM-97 PTP Clock-1 to use the Sync-E clock as the reference frequency through the SSU:
*A:SARM-96# configure system ptp clock 1
*A:SARM-96>config>system>ptp>clock># shutdown
*A:SARM-96>config>system>ptp>clock># freq-source ssu
*A:SARM-96>config>system>ptp>clock># no shutdown
*A:SARM-96>config>system>ptp>clock># info
----------------------------------------------
source-interface "ptp1-OStoGM"
clock-mda 1/1
freq-source ssu
ptp-port 1
peer 1
description "to-GM"
ip-address 10.189.2.2
exit
peer 2
exit
no shutdown
exit
no shutdown
----------------------------------------------
- Verify the SARM-97 1PPS output uses the Sync-E clock as the reference frequency:
* *A:SARM-96# show system ptp clock 1
===============================================================================
IEEE1588 PTP Clock Information
===============================================================================
-------------------------------------------------------------------------------
Local Clock
-------------------------------------------------------------------------------
Clock Type :
ordinary,slave
Source I/F : ptp1-OStoGM Clock MDA : 1/1
PTP Profile : ieee1588-2008 Dynamic Peers : not allowed
Admin Freq-source : ssu Oper Freq-source : ssu
Clock ID : 38521afffeed053c Clock Class : 255
Clock Accuracy : unknown(254) Clock Variance : not computed
Clock Priority1 : 128 Clock Priority2 : 128
Domain : 0 Two-Step : unknown
-------------------------------------------------------------------------------
Parent Clock
-------------------------------------------------------------------------------
Parent Clock ID : 8887868584838281
GM Clock Id : 8887868584838281 GM Clock Class : 6
GM Clock Accuracy : 100ns GM Clock Variance : 25600
GM Clock Priority1 : 128 GM Clock Priority2 : 128
-------------------------------------------------------------------------------
Slave Peer Index : 1 Slave Peer IP : 10.189.2.2
-------------------------------------------------------------------------------
Time Information
-------------------------------------------------------------------------------
Timescale : PTP
Current Time : -
Freq Traceable : true
Time Traceable : true
Time Source : gps
===============================================================================
