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)