NAME

       nsm - NetSync Monitor client

SYNOPSIS

       nsm [ -f config ] [ -i interface ] [ long-options ] [ command ] ...

DESCRIPTION

       nsm  is  a  program which implements a NetSync Monitor (NSM) client. NSM is an extension to the Precision
       Time Protocol (PTP), which enables a client to measure the offset of its clock against any PTP  clock  in
       the  network which supports NSM. It uses unicast messages, but unlike PTP in the unicast mode it does not
       require the server to keep any state specific to the client. It is particularly useful for monitoring.

       The program reads commands from the standard input or from the command line.

COMMANDS

       NSM address
              Send a NetSync Monitor request to the specified network  address  (IPv4  or  MAC)  and  print  the
              measured offset with the response.

       help   Display a help message.

OPTIONS

       -f config
              Read configuration from the specified file. No configuration file is read by default.

       -i interface
              Specify the network interface.

       -h     Display a help message.

       -v     Print the software version and exit.

LONG OPTIONS

       Each  and  every  configuration  file option (see below in sections PROGRAM OPTIONS and PORT OPTIONS) may
       also appear as a "long" style command line argument. For example, the transportSpecific option may be set
       using either of these two forms:

              --transportSpecific 1   --transportSpecific=1

       Option  values  given on the command line override values in the global section of the configuration file
       (which, in turn, overrides default values).

CONFIGURATION FILE

       The configuration file is divided into sections. Each section starts with  a  line  containing  its  name
       enclosed  in  brackets  and  it  follows  with  settings.   Each setting is placed on a separate line, it
       contains the name of the option and the value separated by whitespace characters. Empty lines  and  lines
       starting with # are ignored.

       The  global  section  (indicated as [global]) sets the global program options as well as the default port
       specific options.  Other sections are port specific sections and they override the default port  options.
       The name of the section is the name of the configured port (e.g.  [eth0] ).

PORT OPTIONS

       delayAsymmetry
              The  time  difference  in  nanoseconds  of  the  transmit  and receive paths. This value should be
              positive when the master-to-slave propagation time is longer and negative when the slave-to-master
              time is longer. The default is 0 nanoseconds.

       network_transport
              Select the network transport. Possible values are UDPv4 and L2. The default is UDPv4.

       transportSpecific
              The transport specific field. Must be in the range 0 to 255.  The default is 0.

PROGRAM OPTIONS

       domainNumber
              The  domain  attribute  of  the  local  clock.  The default is 0.  time_stamping The time stamping
              method. The allowed values are hardware, software and legacy.  The default is hardware.

WARNING

       Be cautious when the same configuration file is used for both ptp4l and nsm.  Keep in  mind  that  values
       specified  in the configuration file take precedence over their default values. If a certain option which
       is common to ptp4l and nsm is specified to a non-default  value  in  the  configuration  file  (e.g.  for
       ptp4l), then this non-default value applies also for nsm. This might be not what is expected.

       To  avoid  securely  these  unexpected  behaviour,  different  configuration  files for ptp4l and nsm are
       recommended.

SEE ALSO

       ptp4l(8)