Provided by: linuxptp_3.1.1-4_amd64 bug

NAME

       ptp4l - PTP Boundary/Ordinary/Transparent Clock

SYNOPSIS

       ptp4l [ -AEP246HSLmqsv ] [ -f config ] [ -p phc-device ] [ -l print-level ] [ -i interface
       ] [ long-options ] ...

DESCRIPTION

       ptp4l is an implementation of the Precision Time Protocol (PTP) according to IEEE standard
       1588  for  Linux.  It implements Boundary Clock (BC), Ordinary Clock (OC), and Transparent
       Clock (TC).

OPTIONS

       -A     Select the delay mechanism automatically. Start with E2E and switch to P2P  when  a
              peer delay request is received.

       -E     Select  the  delay request-response (E2E) mechanism. This is the default mechanism.
              All clocks on single PTP communication path must use the same mechanism. A  warning
              will  be  printed  when  a  peer  delay  request  is received on port using the E2E
              mechanism.

       -P     Select the peer delay (P2P) mechanism. A warning  will  be  printed  when  a  delay
              request is received on port using the P2P mechanism.

       -2     Select the IEEE 802.3 network transport.

       -4     Select the UDP IPv4 network transport. This is the default transport.

       -6     Select the UDP IPv6 network transport.

       -H     Select  the hardware time stamping. All ports specified by the -i option and in the
              configuration file must be attached to the same PTP hardware clock (PHC).  This  is
              the default time stamping.

       -S     Select the software time stamping.

       -L     Select the legacy hardware time stamping.

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

       -i interface
              Specify a PTP port, it may be used multiple  times.  At  least  one  port  must  be
              specified by this option or in the configuration file.

       -p phc-device
              (This option is deprecated.)  Before Linux kernel v3.5 there was no way to discover
              the PHC device associated with a network interface.  This option specifies the  PHC
              device (e.g. /dev/ptp0) to be used when running on legacy kernels.

       -s     Enable the slaveOnly mode.

       -l print-level
              Set  the  maximum  syslog  level of messages which should be printed or sent to the
              system logger. The default is 6 (LOG_INFO).

       -m     Print messages to the standard output.

       -q     Don't send messages to the system logger.

       -v     Prints the software version and exits.

       -h     Display a help message.

LONG OPTIONS

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

              --slaveOnly 1   --slaveOnly=1

       Option values given on the command line override values  in  the  global  section  of  the
       configuration file.

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.

       There are three different section types.

       1.     The global section (indicated as [global]) sets the program options, clock  options
              and  default  port  options.  Other  sections  are  port specific sections and they
              override the default port options.

       2.     Port sections give the name of the configured port (e.g.  [eth0]).  Ports specified
              in  the  configuration  file  don't need to be specified by the -i option. An empty
              port section can be used to replace the command line option.

       3.     Tables for configuring unicast discovery begin with [unicast_master_table].

              See UNICAST DISCOVERY OPTIONS, below.

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.

       logAnnounceInterval
              The mean time interval between Announce messages. A shorter  interval  makes  ptp4l
              react  faster  to the changes in the master-slave hierarchy. The interval should be
              the same in the whole domain. It's specified as a power of  two  in  seconds.   The
              default is 1 (2 seconds).

       logSyncInterval
              The  mean  time  interval  between  Sync  messages.  A shorter interval may improve
              accuracy of the local clock. It's specified as a power  of  two  in  seconds.   The
              default is 0 (1 second).

       operLogSyncInterval
              The   Sync   message   interval   to   be  requested  once  the  clock  enters  the
              SERVO_LOCKED_STABLE state.  If the 'msg_interval_request' option is set,  then  the
              local slave port will request the remote master to switch to the given message rate
              via a signaling message containing a Message interval request TLV.  This option  is
              specified as a power of two in seconds, and default value is 0 (1 second).

       logMinDelayReqInterval
              The  minimum  permitted  mean  time  interval between Delay_Req messages. A shorter
              interval makes ptp4l react faster to the changes in the path delay. It's  specified
              as a power of two in seconds.  The default is 0 (1 second).

       logMinPdelayReqInterval
              The  minimum  permitted  mean  time  interval  between  Pdelay_Req  messages.  It's
              specified as a power of two in seconds.  The default is 0 (1 second).

       operLogPdelayReqInterval
              The Pdelay Request  messages  interval  to  be  used  once  the  clock  enters  the
              SERVO_LOCKED_STABLE  state.   If the 'msg_interval_request' option is set, then the
              local slave port will adopt this rate when  the  local  clock  enters  the  "locked
              stable"  state.   This  option  is  specified as a power of two in seconds, and the
              default value is 0 (1 second).

       inhibit_delay_req
              Don't send any delay requests. This will need the asCapable config option to be set
              to  'true'. This is useful when running as a designated master who does not need to
              calculate offset from slave. The default is 0 (disabled).

       announceReceiptTimeout
              The number of missed Announce messages before the last Announce  messages  expires.
              The default is 3.

       syncReceiptTimeout
              The  number of sync/follow up messages that may go missing before triggering a Best
              Master Clock election. This option is used for running in gPTP  mode  according  to
              the  802.1AS-2011  standard.  Setting  this  option  to  zero will disable the sync
              message timeout.  The default is 0 or disabled.

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

       ignore_transport_specific
              By default, incoming messages are dropped if their transportSpecific field does not
              match  the  configured  value.   However,  many of transports specified in the 1588
              standard mandate ignoring this field.  Moreover, some equipment is known to set the
              reserved  bits.   Configuring  this  option  as  1  causes this field to be ignored
              completely on receive.  The default is 0.

       path_trace_enabled
              Enable the mechanism used to trace the route of the Announce messages.  The default
              is 0 (disabled).

       follow_up_info
              Include  the  802.1AS  data in the Follow_Up messages if enabled.  The default is 0
              (disabled).

       fault_reset_interval
              The time in seconds between the detection of a port's fault  and  the  fault  being
              reset.  This value is expressed as a power of two. Setting this value to -128 or to
              the special key word "ASAP" will let the fault be reset immediately.   The  default
              is 4 (16 seconds).

       fault_badpeernet_interval
              The  time  in  seconds between the detection of a peer network misconfiguration and
              the fault being reset. The port is disabled for the duration of the  interval.  The
              value  is  in  seconds  and  the  special key word ASAP will let the fault be reset
              immediately.  The default is 16 seconds.

       delay_mechanism
              Select the delay mechanism. Possible values are E2E, P2P and Auto.  The default  is
              E2E.

       hybrid_e2e
              Enables  the  "hybrid"  delay  mechanism  from  the  draft Enterprise Profile. When
              enabled, ports in the slave state send their delay request messages to the  unicast
              address  taken  from  the master's announce message. Ports in the master state will
              reply to unicast delay requests using unicast delay responses. This option  has  no
              effect if the delay_mechanism is set to P2P.  The default is 0 (disabled).

       inhibit_multicast_service
              Some  unicast  mode profiles insist that no multicast message are ever transmitted.
              Setting this option inhibits multicast transmission.  The default is  0  (mutlicast
              enabled).

       net_sync_monitor
              Enables  the  NetSync  Monitor (NSM) protocol. The NSM protocol allows a station to
              measure how well another node is synchronized. The monitor sends  a  unicast  delay
              request  to  the  node,  which replies unconditionally with unicast delay response,
              sync, and follow up messages. If the monitor is synchronized to the GM, it can  use
              the time stamps in the message to estimate the node's offset.  This option requires
              that the 'hybrid_e2e' option be enabled as well.  The default is 0 (disabled).

       unicast_listen
              When enabled, this option allows the  port  to  grant  unicast  message  contracts.
              Incoming  requests  for  will  be  granted  limited  only  by  the amount of memory
              available.  The default is 0 (disabled).

       unicast_master_table
              When set to a positive integer, this option specifies the table id to be  used  for
              unicast  discovery.  Each table lives in its own section and has a unique, positive
              numerical ID.  Entries in the table are a  pair  of  transport  type  and  protocol
              address.  The default is 0 (unicast discovery disabled).

       unicast_req_duration
              The  service  time  in seconds to be requested during unicast discovery.  Note that
              the remote node is free to grant a different duration.  The default is 3600 seconds
              or one hour.

       ptp_dst_mac
              The  MAC  address  to  which  PTP  messages  should be sent.  Relevant only with L2
              transport. The default is 01:1B:19:00:00:00.

       p2p_dst_mac
              The MAC address to which peer delay messages should be sent.  Relevant only with L2
              transport. The default is 01:80:C2:00:00:0E.

       network_transport
              Select the network transport. Possible values are UDPv4, UDPv6 and L2.  The default
              is UDPv4.

       neighborPropDelayThresh
              Upper limit for peer delay in nanoseconds. If the estimated peer delay  is  greater
              than this value the port is marked as not 802.1AS capable.

       masterOnly
              Setting  this option to one (1) prevents the port from entering the SLAVE state. In
              addition, the local clock will ignore Announce messages received on this port. This
              option's  intended  use  is  to  support  the  Telecom  Profiles according to ITU-T
              G.8265.1, G.8275.1, and G.8275.2. The default value is zero or false.

       G.8275.portDS.localPriority
              The Telecom Profiles (ITU-T G.8275.1 and G.8275.2) specify an alternate Best Master
              Clock  Algorithm  (BMCA) with a unique data set comparison algorithm.  The value of
              this option is associated with Announce messages arriving on a particular port  and
              is    used    as    a    tie    breaker    whenever    clockClass,   clockAccuracy,
              offsetScaledLogVariance, and priority2 are equal. This option  is  only  used  when
              "dataset_comparison" is set to "telecom".  The default value is 128.

              Warning:  the  BMCA  is  guaranteed  to  produce a spanning tree (that is, a timing
              network   without   loops)   only   when    using    the    default    values    of
              G.8275.defaultDS.localPriority  and  G.8275.portDS.localPriority.   Careful network
              engineering is needed when using non-default values.

       min_neighbor_prop_delay
              Lower limit for peer delay in nanoseconds. If the estimated peer delay  is  smaller
              than this value the port is marked as not 802.1AS capable.

       tsproc_mode
              Select the time stamp processing mode used to calculate offset and delay.  Possible
              values are filter, raw, filter_weight, raw_weight. Raw modes perform well when  the
              rate  of  sync  messages (logSyncInterval) is similar to the rate of delay messages
              (logMinDelayReqInterval  or  logMinPdelayReqInterval).  Weighting  is  useful  with
              larger network jitters (e.g. software time stamping).  The default is filter.

       delay_filter
              Select  the  algorithm  used  to filter the measured delay and peer delay. Possible
              values are moving_average and moving_median.  The default is moving_median.

       delay_filter_length
              The length of the delay filter in samples.  The default is 10.

       egressLatency
              Specifies the difference in nanoseconds between the actual transmission time at the
              reference  plane  and the reported transmit time stamp. This value will be added to
              egress time stamps obtained from the hardware.  The default is 0.

       ingressLatency
              Specifies the difference in nanoseconds between the reported receive time stamp and
              the  actual  reception  time at reference plane. This value will be subtracted from
              ingress time stamps obtained from the hardware.  The default is 0.

       boundary_clock_jbod
              When running as a boundary clock (that is, when more than one network interface  is
              configured), ptp4l performs a sanity check to make sure that all of the ports share
              the same hardware clock device. This option allows ptp4l  to  work  as  a  boundary
              clock  using "just a bunch of devices" that are not synchronized to each other. For
              this mode, the collection of clocks must be synchronized by  an  external  program,
              for example phc2sys(8) in "automatic" mode.  The default is 0 (disabled).

       udp_ttl
              Specifies  the  Time  to  live  (TTL) value for IPv4 multicast messages and the hop
              limit for IPv6 multicast messages. This option is only relevant with the  IPv4  and
              IPv6 UDP transports. The default is 1 to restrict the messages sent by ptp4l to the
              same subnet.

PROGRAM AND CLOCK OPTIONS

       twoStepFlag
              Enable two-step mode for sync  messages.  One-step  mode  can  be  used  only  with
              hardware time stamping.  The default is 1 (enabled).

       slaveOnly
              The local clock is a slave-only clock if enabled. The default is 0 (disabled).

       socket_priority
              Configure  the  SO_PRIORITY of sockets. This is to support cases where a user wants
              to route ptp4l traffic using Linux qdiscs for the purpose of traffic shaping.  This
              option  is  only  available  with  the  IEEE 802.3 transport (the -2 option) and is
              silently ignored when using the UDP IPv4/6 network transports. Must be in the range
              of 0 to 15, inclusive. The default is 0.

       gmCapable
              If  this  option  is  enabled, then the local clock is able to become grand master.
              This is only for use with 802.1AS clocks and has no effect  on  1588  clocks.   The
              default is 1 (enabled).

       priority1
              The priority1 attribute of the local clock. It is used in the best master selection
              algorithm, lower values take precedence. Must be  in  the  range  0  to  255.   The
              default is 128.

       priority2
              The priority2 attribute of the local clock. It is used in the best master selection
              algorithm, lower values take precedence. Must be  in  the  range  0  to  255.   The
              default is 128.

       clockClass
              The  clockClass  attribute  of  the local clock. It denotes the traceability of the
              time distributed by the grandmaster clock.  The default is 248.

       clockAccuracy
              The clockAccuracy attribute of the local clock. It  is  used  in  the  best  master
              selection algorithm.  The default is 0xFE.

       clockIdentity
              The  clockIdentity  attribute  of the local clock.  The clockIdentity is an 8-octet
              array and should in this configuration be written in textual form, see default.  It
              should  be  unique  since it is used to identify the specific clock.  If default is
              used or if not set at all, the clockIdentity will be automtically  generated.   The
              default is "000000.0000.000000"

       offsetScaledLogVariance
              The  offsetScaledLogVariance  attribute  of  the  local clock. It characterizes the
              stability of the clock.  The default is 0xFFFF.

       G.8275.defaultDS.localPriority
              The Telecom Profiles (ITU-T G.8275.1 and G.8275.2) specify an alternate Best Master
              Clock  Algorithm  (BMCA) with a unique data set comparison algorithm.  The value of
              this option is associated with the local  clock  and  is  used  as  a  tie  breaker
              whenever  clockClass,  clockAccuracy,  offsetScaledLogVariance,  and  priority2 are
              equal. This option is only used when "dataset_comparison" is set to "telecom".  The
              default value is 128.

              Warning:  the  BMCA  is  guaranteed  to  produce a spanning tree (that is, a timing
              network   without   loops)   only   when    using    the    default    values    of
              G.8275.defaultDS.localPriority  and  G.8275.portDS.localPriority.   Careful network
              engineering is needed when using non-default values.

       maxStepsRemoved
              When using this option, if the value of stepsRemoved  of  an  Announce  message  is
              greater  than  or equal to the value of maxStepsRemoved the Announce message is not
              considered in the operation of the BMCA.  The default value is 255.

       domainNumber
              The domain attribute of the local clock.  The default is 0.

       utc_offset
              The current offset between TAI and UTC.  The default is 37.

       free_running
              Don't adjust the local clock if enabled.  The default is 0 (disabled).

       freq_est_interval
              The time interval over which is estimated the ratio of the  local  and  peer  clock
              frequencies.  It  is  specified  as a power of two in seconds.  The default is 1 (2
              seconds).

       assume_two_step
              Treat one-step responses as two-step if enabled. It is used to  work  around  buggy
              802.1AS switches.  The default is 0 (disabled).

       tc_spanning_tree
              When running as a Transparent Clock, increment the "stepsRemoved" field of Announce
              messages that pass through the switch.   Enabling  this  option  ensures  that  PTP
              message  loops never form, provided the switches all implement this option together
              with the BMCA.

       tx_timestamp_timeout
              The number of milliseconds to poll waiting for the tx time stamp  from  the  kernel
              when a message has recently been sent.  The default is 1.

       check_fup_sync
              Because  of packet reordering that can occur in the network, in the hardware, or in
              the networking stack, a follow up message can appear to arrive in  the  application
              before  the  matching  sync  message.  As  this  is  a  normal  occurrence, and the
              sequenceID message field ensures proper matching, the ptp4l program accepts out  of
              order  packets. This option adds an additional check using the software time stamps
              from the networking stack to verify that the sync message did  arrive  first.  This
              option is only useful if you do not trust the sequence IDs generated by the master.
              The default is 0 (disabled).

       clock_servo
              The servo which is used to synchronize the local clock. Valid values are "pi" for a
              PI  controller,  "linreg"  for  an  adaptive  controller  using  linear regression,
              "ntpshm" for the NTP SHM reference clock to allow another  process  to  synchronize
              the  local  clock (the SHM segment number is set to the domain number), and "nullf"
              for a servo that always dials frequency offset zero (for use in SyncE nodes).   The
              default is "pi."

       clock_type
              Specifies  the  kind  of PTP clock.  Valid values are "OC" for ordinary clock, "BC"
              for boundary clock, "P2P_TC" for peer to peer transparent clock, and  "E2E_TC"  for
              end  to  end transparent clock.  An multi-port ordinary clock will automatically be
              configured as a boundary clock.  The default is "OC".

       pi_proportional_const
              The proportional constant of the PI controller. When set to 0.0,  the  proportional
              constant  will be set by the following formula from the current sync interval.  The
              default is 0.0.

              kp = min(kp_scale * sync^kp_exponent, kp_norm_max / sync)

       pi_integral_const
              The integral constant of the PI controller. When set to 0.0, the integral  constant
              will  be  set by the following formula from the current sync interval.  The default
              is 0.0.

              ki = min(ki_scale * sync^ki_exponent, ki_norm_max / sync)

       pi_proportional_scale
              The kp_scale constant in the formula used to set the proportional constant  of  the
              PI  controller  from the sync interval. When set to 0.0, the value will be selected
              from 0.7 and 0.1 for the hardware and software  time  stamping  respectively.   The
              default is 0.0.

       pi_proportional_exponent
              The  kp_exponent  constant  in the formula used to set the proportional constant of
              the PI controller from the sync interval.  The default is -0.3.

       pi_proportional_norm_max
              The kp_norm_max constant in the formula used to set the  proportional  constant  of
              the PI controller from the sync interval.  The default is 0.7

       pi_integral_scale
              The  ki_scale  constant  in the formula used to set the integral constant of the PI
              controller from the sync interval. When set to 0.0, the value will be selected from
              0.3  and  0.001  for  the  hardware  and  software time stamping respectively.  The
              default is 0.0.

       pi_integral_exponent
              The ki_exponent constant in the formula used to set the integral constant of the PI
              controller from the sync interval.  The default is 0.4.

       pi_integral_norm_max
              The ki_norm_max constant in the formula used to set the integral constant of the PI
              controller from the sync interval.  The default is 0.3.

       step_threshold
              The maximum offset the servo will correct by changing the clock  frequency  instead
              of  stepping the clock. When set to 0.0, the servo will never step the clock except
              on start. It's specified in seconds.  The default is 0.0.  This option used  to  be
              called pi_offset_const.

       first_step_threshold
              The  maximum  offset the servo will correct by changing the clock frequency instead
              of stepping the clock. This is only applied on the first update. It's specified  in
              seconds.  When set to 0.0, the servo won't step the clock on start.  The default is
              0.00002 (20 microseconds).  This option used to be called pi_f_offset_const.

       max_frequency
              The maximum allowed frequency adjustment of the clock in parts per  billion  (ppb).
              This  is an additional limit to the maximum allowed by the hardware. When set to 0,
              the hardware limit will be used.  The default is 900000000 (90%).  This option used
              to be called pi_max_frequency.

       sanity_freq_limit
              The  maximum  allowed  frequency  offset  between  uncorrected clock and the system
              monotonic clock in parts per billion (ppb). This is used as a sanity check  of  the
              synchronized  clock.  When  a  larger offset is measured, a warning message will be
              printed and the servo will be reset. When set to 0, the sanity check  is  disabled.
              The default is 200000000 (20%).

       initial_delay
              The  initial path delay of the clock in nanoseconds used for synchronization of the
              clock before the delay is measured using the E2E or P2P delay mechanism. If set  to
              0, the clock will not be updated until the delay is measured.  The default is 0.

       ntpshm_segment
              The number of the SHM segment used by ntpshm servo.  The default is 0.

       udp6_scope
              Specifies  the desired scope for the IPv6 multicast messages.  This will be used as
              the second byte of the primary address.  This option is  only  relevant  with  IPv6
              transport.  See RFC 4291.  The default is 0x0E for the global scope.

       uds_address
              Specifies  the  address  of  the  UNIX domain socket for receiving local management
              messages. The default is /var/run/ptp4l.

       dscp_event
              Defines the Differentiated Services Codepoint (DSCP)  to  be  used  for  PTP  event
              messages.  Must  be  a  value  between  0 and 63. There are several media streaming
              standards out there that require specific values for this option.  For  example  46
              (EF PHB) in AES67 or 48 (CS6 PHB) in RAVENNA. The default is 0.

       dscp_general
              Defines  the  Differentiated  Services  Codepoint (DSCP) to be used for PTP general
              messages. Must be a value between 0 and  63.  There  are  several  media  streaming
              standards out there that recommend specific values for this option.  For example 34
              (AF41 PHB) in AES67 or 46 (EF PHB) in RAVENNA. The default is 0.

       dataset_comparison
              Specifies the method to be used when comparing data sets  during  the  Best  Master
              Clock  Algorithm.   The possible values are "ieee1588" and "G.8275.x".  The default
              is "ieee1588".

       logging_level
              The maximum logging level of messages which should be printed.  The  default  is  6
              (LOG_INFO).

       message_tag
              The  tag  which  is  added to all messages printed to the standard output or system
              log.  The default is an empty string (which cannot be set in the configuration file
              as the option requires an argument).

       verbose
              Print messages to the standard output if enabled.  The default is 0 (disabled).

       use_syslog
              Print messages to the system log if enabled.  The default is 1 (enabled).

       summary_interval
              The  time  interval  in  which  are  printed summary statistics of the clock. It is
              specified as a power of two in seconds. The statistics  include  offset  root  mean
              square   (RMS),  maximum  absolute  offset,  frequency  offset  mean  and  standard
              deviation, and path delay mean and standard deviation. The  units  are  nanoseconds
              and parts per billion (ppb). If there is only one clock update in the interval, the
              sample will be printed instead of the statistics. The messages are printed  at  the
              LOG_INFO level.  The default is 0 (1 second).

       time_stamping
              The  time  stamping  method.  The allowed values are hardware, software and legacy.
              The default is hardware.

       productDescription
              The  product  description  string.   Allowed   values   must   be   of   the   form
              manufacturerName;modelNumber;instanceIdentifier   and   contain  at  most  64  utf8
              symbols. The default is ";;".

       revisionData
              The revision description string which contains  the  revisions  for  node  hardware
              (HW), firmware (FW), and software (SW). Allowed values are of the form HW;FW;SW and
              contain at most 32 utf8 symbols. The default is an ";;".

       userDescription
              The user description string. Allowed values  are  of  the  form  name;location  and
              contain at most 128 utf8 symbols. The default is an empty string.

       manufacturerIdentity
              The  manufacturer id which should be an OUI owned by the manufacturer.  The default
              is 00:00:00.

       kernel_leap
              When a leap second is announced, let the kernel apply  it  by  stepping  the  clock
              instead  of  correcting  the  one-second offset with servo, which would correct the
              one-second offset slowly by changing the clock frequency (unless the step_threshold
              option  is  set  to  correct such offset by stepping).  Relevant only with software
              time stamping. The default is 1 (enabled).

       timeSource
              The time source is a single byte code that gives an idea of the kind of local clock
              in  use.  The value is purely informational, having no effect on the outcome of the
              Best Master Clock algorithm, and is advertised when the clock becomes grand master.

       hwts_filter
              Select the hardware time stamp filter setting mode.  Possible  values  are  normal,
              check,  full.  Normal mode set the filters as needed.  Check mode only check but do
              not set.  Full mode set the receive filter to mark all packets with  hardware  time
              stamp,
               so all applications can get them.  The default is normal.

       asCapable
              If  set  to 'true', all the checks which can unset asCapable variable (as described
              in Section 10.2.4.1 of 802.1AS)  are  skipped.  If  set  to  'auto',  asCapable  is
              initialized  to  'false'  and  will be set to 'true' after the relevant checks have
              passed. The default value is 'auto'.

       BMCA   This option enables use of static roles for master and  slave  devices  instead  of
              running  the  best master clock algorithm (BMCA) described in 1588 profile. This is
              useful when you know the roles of the devices in advance. When set to  ┬┤noop',  the
              traditional  BMCA  algorithm used by 1588 is skipped. masterOnly and slaveOnly will
              be used to determine master or slave role for the device. In  a  bridge,  slaveOnly
              (which  is  a  global  option)  can be set to make all ports assume the slave role.
              masterOnly (which is a per-port config option) can then be used to  set  individual
              ports  to  take master role. BMCA is used in the Automotive profile to speed up the
              start time for grand master and slaves. The default value is 'ptp' which  runs  the
              BMCA related state machines.

       inhibit_announce
              This  will  disable  the timer for announce messages (i.e. FD_MANNO_TIMER) and also
              the announce message timeout timer (i.e. FD_ANNOUNCE_TIMER). This is  used  by  the
              Automotive  profile  as  part of switching over to a static BMCA. if this option is
              enabled, ignore_source_id has to be enabled in the slave because it has no  way  to
              identify  master  identity  in  Sync  and  Follow_Up  messages.  The  default  is 0
              (disabled).

       ignore_source_id
              This will disable source port identity checking for Sync  and  Follow_Up  messages.
              This  is useful when the announce messages are disabled in the master and the slave
              does not have any way to know it's identity. The default is 0 (disabled).

       msg_interval_request
              This option, when set, will trigger an  adjustment  to  the  Sync  and  peer  delay
              request   message   intervals   when   the   clock   servo   transitions  into  the
              SERVO_LOCKED_STABLE state.  The Sync interval will be adjusted  via  the  signaling
              mechanism while the pdelay request interval is simply adjusted locally.  The values
              to use for the new Sync and peer delay  request  intervals  are  specified  by  the
              operLogSyncInterval   and   operLogPdelayReqInterval  options,  respectively.   The
              default value of msg_interval_request is 0 (disabled).

       servo_num_offset_values
              The number of offset values considered in order to transition from the SERVO_LOCKED
              to   the   SERVO_LOCKED_STABLE   state.    The  transition  occurs  once  the  last
              'servo_num_offset_values' offsets are all below the 'servo_offset_threshold' value.
              The default value is 10.

       servo_offset_threshold
              The  offset  threshold  used  in  order  to transition from the SERVO_LOCKED to the
              SERVO_LOCKED_STABLE state.  The transition occurs once the last The  default  value
              of offset_threshold is 0 (disabled).

       slave_event_monitor
              Specifies  the address of a UNIX domain socket for slave event monitoring.  A local
              client  bound  to  this  address   will   receive   SLAVE_RX_SYNC_TIMING_DATA   and
              SLAVE_DELAY_TIMING_DATA_NP TLVs.  The default is the empty string (disabled).

       write_phase_mode
              This  option  enables  using the "write phase" feature of a PTP Hardware Clock.  If
              supported by the device, this mode  uses  the  hardware's  built  in  phase  offset
              control instead of frequency offset control.  The default value is 0 (disabled).

UNICAST DISCOVERY OPTIONS

       table_id
              Each  table  must  begin  with a unique, positive table ID.  The port that claims a
              given table does so by including the ID as the value of its  'unicast_master_table'
              option.

       logQueryInterval
              This  option  configures the time to wait between unicast negotiation attempts.  It
              is specified as a power of two in seconds.  The default is 0 (1 second).

       peer_address
              This option specifies the unicast address of the peer for use with the peer to peer
              delay  mechanism.   If  specified, the port owning the table will negotiate unicast
              peer delay responses from the machine at the given remote  address,  otherwise  the
              port will send multicast peer delay requests.

       L2|UDPv4|UDPv6
              Each  table  entry  specifies the transport type and network address of a potential
              remote master.  If multiple masters are specified, then unicast negotiation will be
              performed with each if them.

TIME SCALE USAGE

       ptp4l  as domain master either uses PTP or UTC time scale depending on time stamping mode.
       In software and legacy time stamping modes it announces Arbitrary time scale  mode,  which
       is  effectively  UTC  here,  in  hardware  time stamping mode it announces use of PTP time
       scale.

       When ptp4l is the domain master using hardware time stamping,  it  is  up  to  phc2sys  to
       maintain the correct offset between UTC and PTP times. See phc2sys(8) manual page for more
       details.

SEE ALSO

       pmc(8), phc2sys(8)