7705 SAR

R5.0 Configuration Note

 

 

 

 

 

 

 

 

 


SAR

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   Admin State          : up

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 Parent Port Number   : 1

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 Port Index     : 1                Slave Port State     : slave

Slave Peer Index     : 1                Slave Peer IP        : 10.189.2.2

Forward Weight       : 100              Reverse Weight       : 0

Recovery State       : locked           

-------------------------------------------------------------------------------

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 Second Port

===============================================================================

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

    Source Port                    : None

 

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

    Source Port                    : None

 

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

    Source Port                    : 1/1/1

 

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

    Source Port                    : None

 

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   Admin State          : up

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 Parent Port Number   : 1

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 Port Index     : 1                Slave Port State     : slave

Slave Peer Index     : 1                Slave Peer IP        : 10.189.2.2

Recovery State       : free-run        

-------------------------------------------------------------------------------

Time Information

-------------------------------------------------------------------------------

Timescale            : PTP             

Current Time         : -               

Freq Traceable       : true             

Time Traceable       : true            

Time Source          : gps             

===============================================================================