Table of contents

1. Introduction
2. Compilation
3. Installation
4. Usage
5. Config

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1. Introduction

synce4l is a software implementation of Synchronous Ethernet (SyncE) according to ITU-T Recommendation G.8264. The design goal is to provide logic to supported hardware by processing Ethernet Synchronization Messaging Channel (ESMC) and control Ethernet Equipment Clock (EEC) on Network Card Interface (NIC).

Application can operate in two mutually exclusive input modes: line or external. Both modes are described in next paragraphs.

The best source selection is done according to ITU-T Recommendations G.781 and G.8264. Two network options are supported: option 1 and option 2.

Table showing priority of quality levels (QLs) in option 1 networks:

Quality Level	Priority*	SSM	Extended SSM**
ePRTC	0	0x2	0x21
PRTC	1	0x2	0x20
PRC	2	0x2	0xFF
SSU-A	3	0x4	0xFF
SSU-B	4	0x8	0xFF
EEC1	5	0xB	0xFF

Table showing priority of quality levels (QLs) in option 2 networks:

Quality Level	Priority*	SSM	Extended SSM**
ePRTC	0	0x1	0x21
PRTC	1	0x1	0x20
PRS	2	0x1	0xFF
STU	3	0x0	0xFF
ST2	4	0x7	0xFF
TNC	5	0x4	0xFF
ST3E	6	0xD	0xFF
EEC2	7	0xA	0xFF
PROV	8	0xE	0xFF

Remark: *Lower number means higher priority

Remark: **If extended SSM is not enabled, it's implicitly assumed as 0xFF

External input mode

If synce4l is configured to run in external input mode then EEC needs to have external 1PPS source attached (GPS or other generator). In this scenario synce4l always broadcasts clock quality level (QL) defined in configuration file. Additionally, for “external” mode incoming SyncE frames do not participate in best source selection algorithm for EEC.

Line input mode

In line input mode incoming SyncE frames are processed and best clock source is extracted from the link having the best quality level. synce4l configures such "best quality" port as a source to recover clock for EEC. The recovered QL is broadcasted to all other interfaces then. An external clock cannot be used in this mode.

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2. Compilation

Makefile rules are included in Makefile and compilation is done using the command:

make synce4l

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3. Installation

Use make install target to install synce4l in a system.

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4. Usage

Use -h command line argument to print the help page:

$? ./synce4l -h
usage: synce4l [options]

 ...

 Other Options

 -f [file] read configuration from 'file'
           (config file takes precedence over command line arguments)
 -l [num]  set the logging level to 'num'
           (0: least detailed, 7: most detailed)
 -m        print messages to stdout
 -q        do not print messages to the syslog
 -v        print synce4l version and exit
 -h        print this message and exit

Remark: synce4l requires root privileges since it opens raw sockets.

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5. Config

Configuration file contains three sections:

• global,
• device,
• port.

Global section

This section starts with [global] keyword. It sets the logging options.

Parameter	Default	Valid values	Description
logging_level	6	0-7	Minimum log level required to appear in a log.
message_tag	None	string	Tag reported in a log.
use_syslog	1	0, 1	Set to 1 if syslog should be used.
verbose	0	0, 1	Set to 1 to log extra information.

Device section

This section specifies the configuration of a one logical device e.g. 'synce1'. The name is defined by the user. The name has no impact for any functionality except traces. The name must be enclosed in extra angle bracket when defining new device section e.g. []. All ports defined by port sections after the device section will create one SyncE device (until next device section).

Parameter	Default	Valid values	Description
input_mode	line	line, external	Set to "line" to enable line input mode, set "external" for external input mode.
external_input_QL	0	0-15, 0x0-0xF	Quality Level (QL) for "external input" mode.
external_input_ext_QL	0	0-255,0x0-0xFF	Extended Quality Level for "external input" mode.
extended_tlv	0	0, 1	Set to 1 to enable extended QL.
network_option	1	1, 2	Network option according to T-REC-G.8264. All devices in SyncE domain should have the same option configured.
recover_time	60	10-720	Seconds indicating the minimum time to recover from the QL-failed state on the port.
get_eec_state_cmd	None	string	Shell command which will be executed by synce4l to acquire current state of a SyncE EEC on the device. The command shall output current state of EEC to stdout.
eec_holdover_value	None	string	Value expected on stdout stream when EEC is in HOLDOVER state, after calling command defined in get_eec_state_cmd
eec_locked_ho_value	None	string	Value expected on stdout stream when EEC is in LOCKED HOLDOVER state, after calling command defined in get_eec_state_cmd
eec_locked_value	None	string	Value expected on stdout stream when EEC is in LOCKED state, after calling command defined in get_eec_state_cmd
eec_freerun_value	None	string	Value expected on stdout stream when EEC is in FREERUN state, after calling command defined in get_eec_state_cmd
eec_invalid_value	None	string	Value expected on stdout stream when EEC is in INVALID state, after calling command defined in get_eec_state_cmd

Port section

Any other section not starting with < (e.g. [eth0]) is the port section. Multiple port sections are allowed. Each port participates in SyncE communication.

Parameter	Default	Valid values	Description
tx_heartbeat_msec	1000	100-3000	Interval between consecutive SyncE frame transmissions (1000ms is recommended).
rx_heartbeat_msec	50	10-500	Interval between consecutive SyncE socket polls (frame receive).
recover_clock_enable_cmd	None	string	Shell command which enables PHY port pointed by this Port section as a source of frequency for the SyncE EEC on this device (required only in "internal_input" mode).
recover_clock_disable_cmd	None	string	Shell command which disables PHY port pointed by this Port section as a source of frequency for the SyncE EEC on this device (required only in "internal_input" mode).
allowed_qls	None	string	List of hex values containing allowed SSM QLs separated by comma (,), other received ones would be discarded - if parameter is not provided, all QLs will be accepted.
allowed_ext_qls	None	string	List of hex values containing allowed extended SSM QLs separated by comma (,), other received ones would be discarded - if parameter is not provided, all QLs will be accepted.

Remark: Please do not use backslashes in config file in 'string' fields - for example do not use it like this: "/sys/kernel/debug/ice/0000\:5e\:00\.0/cgu_state"

Config example

[global]
logging_level              7
use_syslog                 0
verbose                    1
message_tag                [synce4l]

[<synce1>]
input_mode                 line
network_option             1
external_input_QL          0x2
external_input_ext_QL      0x20
extended_tlv               1
recover_time               20
eec_get_state_cmd          cat /sys/class/net/eth0/device/dpll_0_state
eec_holdover_value         4
eec_locked_ho_value        3
eec_locked_value           2
eec_freerun_value          1
eec_invalid_value          0

[eth0]
tx_heartbeat_msec          1000
rx_heartbeat_msec          500
recover_clock_enable_cmd   echo 1 0 > /sys/class/net/eth0/device/phy/synce
recover_clock_disable_cmd  echo 0 0 > /sys/class/net/eth0/device/phy/synce
allowed_qls                0x2,0x4,0x8
allowed_ext_qls            0x20,0x21

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