1PTP4l(8) System Manager's Manual PTP4l(8)
2
6 ptp4l - PTP Boundary/Ordinary/Transparent Clock
7
10 ptp4l [ -AEP246HSLmqsv ] [ -f config ] [ -p phc-device ] [ -l print-
11 level ] [ -i interface ] [ long-options ] ...
12
15 ptp4l is an implementation of the Precision Time Protocol (PTP) accord‐
16 ing to IEEE standard 1588 for Linux. It implements Boundary Clock (BC),
17 Ordinary Clock (OC), and Transparent Clock (TC).
18
21 -A Select the delay mechanism automatically. Start with E2E and
22 switch to P2P when a peer delay request is received.
23 -E Select the delay request-response (E2E) mechanism. This is the
25 default mechanism. All clocks on single PTP communication path
26 must use the same mechanism. A warning will be printed when a
27 peer delay request is received on port using the E2E mechanism.
28 -P Select the peer delay (P2P) mechanism. A warning will be printed
30 when a delay request is received on port using the P2P mecha‐
31 nism.
32 -2 Select the IEEE 802.3 network transport.
34 -4 Select the UDP IPv4 network transport. This is the default
36 transport.
37 -6 Select the UDP IPv6 network transport.
39 -H Select the hardware time stamping. All ports specified by the -i
41 option and in the configuration file must be attached to the
42 same PTP hardware clock (PHC). This is the default time stamp‐
43 ing.
44 -S Select the software time stamping.
46 -L Select the legacy hardware time stamping.
48 -f config
50 Read configuration from the specified file. No configuration
51 file is read by default.
52 -i interface
54 Specify a PTP port, it may be used multiple times. At least one
55 port must be specified by this option or in the configuration
56 file.
57 -p phc-device
59 (This option is deprecated.) Before Linux kernel v3.5 there was
60 no way to discover the PHC device associated with a network in‐
61 terface. This option specifies the PHC device (e.g. /dev/ptp0)
62 to be used when running on legacy kernels.
63 -s Enable the clientOnly mode.
65 -l print-level
67 Set the maximum syslog level of messages which should be printed
68 or sent to the system logger. The default is 6 (LOG_INFO).
69 -m Print messages to the standard output.
71 -q Don't send messages to the system logger.
73 -v Prints the software version and exits.
75 -h Display a help message.
77
80 Each and every configuration file option (see below) may also appear as
81 a "long" style command line argument. For example, the clientOnly op‐
82 tion may be set using either of these two forms.
83 --clientOnly 1 --clientOnly=1
85 Option values given on the command line override values in the global
87 section of the configuration file.
88
91 The configuration file is divided into sections. Each section starts
92 with a line containing its name enclosed in brackets and it follows
93 with settings. Each setting is placed on a separate line, it contains
94 the name of the option and the value separated by whitespace charac‐
95 ters. Empty lines and lines starting with # are ignored.
96 There are three different section types.
98 1. The global section (indicated as [global]) sets the program op‐
101 tions, clock options and default port options. Other sections
102 are port specific sections and they override the default port
103 options.
104 2. Port sections give the name of the configured port (e.g.
106 [eth0]). Ports specified in the configuration file don't need
107 to be specified by the -i option. An empty port section can be
108 used to replace the command line option.
109 3. Tables for configuring unicast discovery begin with
111 [unicast_master_table].
112 See UNICAST DISCOVERY OPTIONS, below.
114
117 announceReceiptTimeout
118 The number of missed Announce messages before the last Announce
119 messages expires. The default is 3.
120 boundary_clock_jbod
123 When running as a boundary clock (that is, when more than one
124 network interface is configured), ptp4l performs a sanity check
125 to make sure that all of the ports share the same hardware clock
126 device. This option allows ptp4l to work as a boundary clock us‐
127 ing "just a bunch of devices" that are not synchronized to each
128 other. For this mode, the collection of clocks must be synchro‐
129 nized by an external program, for example phc2sys(8) in "auto‐
130 matic" mode. The default is 0 (disabled).
131 delayAsymmetry
134 The time difference in nanoseconds of the transmit and receive
135 paths. This value should be positive when the server-to-client
136 propagation time is longer and negative when the client-to-
137 server time is longer. The default is 0 nanoseconds.
138 delay_filter
141 Select the algorithm used to filter the measured delay and peer
142 delay. Possible values are moving_average and moving_median.
143 The default is moving_median.
144 delay_filter_length
147 The length of the delay filter in samples. The default is 10.
148 delay_mechanism
151 Select the delay mechanism. Possible values are E2E, P2P, NONE
152 and Auto. The default is E2E.
153 delay_response_timeout
156 The number of delay response messages that may go missing before
157 triggering a synchronization fault. Setting this option to zero
158 will disable the delay response timeout. The default is 0 or
159 disabled.
160 egressLatency
163 Specifies the difference in nanoseconds between the actual
164 transmission time at the reference plane and the reported trans‐
165 mit time stamp. This value will be added to egress time stamps
166 obtained from the hardware. The default is 0.
167 fault_badpeernet_interval
170 The time in seconds between the detection of a peer network mis‐
171 configuration and the fault being reset. The port is disabled
172 for the duration of the interval. The value is in seconds and
173 the special key word ASAP will let the fault be reset immedi‐
174 ately. The default is 16 seconds.
175 fault_reset_interval
178 The time in seconds between the detection of a port's fault and
179 the fault being reset. This value is expressed as a power of
180 two. Setting this value to -128 or to the special key word
181 "ASAP" will let the fault be reset immediately. The default is
182 4 (16 seconds).
183 follow_up_info
186 Include the 802.1AS data in the Follow_Up messages if enabled.
187 The default is 0 (disabled).
188 G.8275.portDS.localPriority
191 The Telecom Profiles (ITU-T G.8275.1 and G.8275.2) specify an
192 alternate Best Master Clock Algorithm (BMCA) with a unique data
193 set comparison algorithm. The value of this option is associ‐
194 ated with Announce messages arriving on a particular port and is
195 used as a tie breaker whenever clockClass, clockAccuracy, off‐
196 setScaledLogVariance, and priority2 are equal. This option is
197 only used when "dataset_comparison" is set to "G.8275.x". The
198 default value is 128.
199 Warning: the BMCA is guaranteed to produce a spanning tree (that
201 is, a timing network without loops) only when using the default
202 values of G.8275.defaultDS.localPriority and G.8275.portDS.lo‐
203 calPriority. Careful network engineering is needed when using
204 non-default values.
205 hybrid_e2e
208 Enables the "hybrid" delay mechanism from the draft Enterprise
209 Profile. When enabled, ports in the client state send their de‐
210 lay request messages to the unicast address taken from the
211 server's announce message. Ports in the server state will reply
212 to unicast delay requests using unicast delay responses. This
213 option has no effect if the delay_mechanism is set to P2P. The
214 default is 0 (disabled).
215 ignore_transport_specific
218 By default, incoming messages are dropped if their transportSpe‐
219 cific field does not match the configured value. However, many
220 of transports specified in the 1588 standard mandate ignoring
221 this field. Moreover, some equipment is known to set the re‐
222 served bits. Configuring this option as 1 causes this field to
223 be ignored completely on receive. The default is 0.
224 ingressLatency
227 Specifies the difference in nanoseconds between the reported re‐
228 ceive time stamp and the actual reception time at reference
229 plane. This value will be subtracted from ingress time stamps
230 obtained from the hardware. The default is 0.
231 inhibit_delay_req
234 Don't send any delay requests. This will need the asCapable con‐
235 fig option to be set to 'true'. This is useful when running as a
236 designated server who does not need to calculate offset from
237 client. The default is 0 (disabled).
238 inhibit_multicast_service
241 Some unicast mode profiles insist that no multicast message are
242 ever transmitted. Setting this option inhibits multicast trans‐
243 mission. The default is 0 (mutlicast enabled).
244 logAnnounceInterval
247 The mean time interval between Announce messages. A shorter in‐
248 terval makes ptp4l react faster to the changes in the
249 client/server hierarchy. The interval should be the same in the
250 whole domain. It's specified as a power of two in seconds. The
251 default is 1 (2 seconds).
252 logMinDelayReqInterval
255 The minimum permitted mean time interval between Delay_Req mes‐
256 sages. A shorter interval makes ptp4l react faster to the
257 changes in the path delay. It's specified as a power of two in
258 seconds. The default is 0 (1 second).
259 logMinPdelayReqInterval
262 The minimum permitted mean time interval between Pdelay_Req mes‐
263 sages. It's specified as a power of two in seconds. The default
264 is 0 (1 second).
265 logSyncInterval
268 The mean time interval between Sync messages. A shorter interval
269 may improve accuracy of the local clock. It's specified as a
270 power of two in seconds. The default is 0 (1 second).
271 masterOnly
274 This option is deprecated and will be removed in a future re‐
275 lease. Use "serverOnly" instead.
276 min_neighbor_prop_delay
279 Lower limit for peer delay in nanoseconds. If the estimated peer
280 delay is smaller than this value the port is marked as not
281 802.1AS capable.
282 neighborPropDelayThresh
285 Upper limit for peer delay in nanoseconds. If the estimated peer
286 delay is greater than this value the port is marked as not
287 802.1AS capable.
288 network_transport
291 Select the network transport. Possible values are UDPv4, UDPv6
292 and L2. The default is UDPv4.
293 net_sync_monitor
296 Enables the NetSync Monitor (NSM) protocol. The NSM protocol al‐
297 lows a station to measure how well another node is synchronized.
298 The monitor sends a unicast delay request to the node, which
299 replies unconditionally with unicast delay response, sync, and
300 follow up messages. If the monitor is synchronized to the GM, it
301 can use the time stamps in the message to estimate the node's
302 offset. This option requires that the 'hybrid_e2e' option be
303 enabled as well. The default is 0 (disabled).
304 operLogPdelayReqInterval
307 The Pdelay Request messages interval to be used once the clock
308 enters the SERVO_LOCKED_STABLE state. If the 'msg_interval_re‐
309 quest' option is set, then the local client port will adopt this
310 rate when the local clock enters the "locked stable" state.
311 This option is specified as a power of two in seconds, and the
312 default value is 0 (1 second).
313 operLogSyncInterval
316 The Sync message interval to be requested once the clock enters
317 the SERVO_LOCKED_STABLE state. If the 'msg_interval_request'
318 option is set, then the local client port will request the re‐
319 mote server to switch to the given message rate via a signaling
320 message containing a Message interval request TLV. This option
321 is specified as a power of two in seconds, and default value is
322 0 (1 second).
323 path_trace_enabled
326 Enable the mechanism used to trace the route of the Announce
327 messages. The default is 0 (disabled).
328 phc_index
331 Specifies the index of the PHC to be used for synchronization
332 with hardware timestamping. This option is useful with virtual
333 clocks running on top of a free-running physical clock (created
334 by writing to /sys/class/ptp/ptp*/n_vclocks). The default is
335 -1, which means the index will be set to the PHC associated with
336 the interface, or the device specified by the -p option.
337 power_profile.2011.grandmasterTimeInaccuracy
340 Specifies the time inaccuracy of the GM in nanoseconds. Rele‐
341 vant only when power_profile.version is 2011. This value may be
342 changed dynamically using the POWER_PROFILE_SETTINGS_NP manage‐
343 ment message. The default is -1 meaning unknown inaccuracy.
344 power_profile.2011.networkTimeInaccuracy
347 Specifies the time inaccuracy of the network in nanoseconds.
348 Relevant only when power_profile.version is 2011. This value
349 may be changed dynamically using the POWER_PROFILE_SETTINGS_NP
350 management message. The default is -1 meaning unknown inaccu‐
351 racy.
352 power_profile.2017.totalTimeInaccuracy
355 Specifies the sum of the GM, network, and local node inaccura‐
356 cies in nanoseconds. Relevant only when power_profile.version
357 is 2017. This value may be changed dynamically using the
358 POWER_PROFILE_SETTINGS_NP management message. The default is -1
359 meaning unknown inaccuracy.
360 power_profile.grandmasterID
363 Specifies an optional, non-zero identification code for the GM.
364 Note that the code is an arbitrary, power profile specific inte‐
365 ger, not necessarily related to the clockIdentity in any way.
366 This value may be changed dynamically using the POWER_PRO‐
367 FILE_SETTINGS_NP management message. The default is 0 meaning
368 unused.
369 power_profile.version
372 Specifies the power profile version to be used. Valid values
373 are "none", "2011", or "2017". This value may be changed dynam‐
374 ically using the POWER_PROFILE_SETTINGS_NP management message.
375 The default is "none".
376 ptp_dst_mac
379 The MAC address to which PTP messages should be sent. Relevant
380 only with L2 transport. The default is 01:1B:19:00:00:00.
381 p2p_dst_mac
384 The MAC address to which peer delay messages should be sent.
385 Relevant only with L2 transport. The default is
386 01:80:C2:00:00:0E.
387 serverOnly
390 Setting this option to one (1) prevents the port from entering
391 the client state. In addition, the local clock will ignore An‐
392 nounce messages received on this port. This option's intended
393 use is to support the Telecom Profiles according to ITU-T
394 G.8265.1, G.8275.1, and G.8275.2. The default value is zero or
395 false.
396 syncReceiptTimeout
399 The number of sync/follow up messages that may go missing before
400 triggering a Best Master Clock election. This option is used for
401 running in gPTP mode according to the 802.1AS-2011 standard.
402 Setting this option to zero will disable the sync message time‐
403 out. The default is 0 or disabled.
404 transportSpecific
407 The transport specific field. Must be in the range 0 to 255.
408 The default is 0.
409 tsproc_mode
412 Select the time stamp processing mode used to calculate offset
413 and delay. Possible values are filter, raw, filter_weight,
414 raw_weight. Raw modes perform well when the rate of sync mes‐
415 sages (logSyncInterval) is similar to the rate of delay messages
416 (logMinDelayReqInterval or logMinPdelayReqInterval). Weighting
417 is useful with larger network jitters (e.g. software time stamp‐
418 ing). The default is filter.
419 udp_ttl
422 Specifies the Time to live (TTL) value for IPv4 multicast mes‐
423 sages and the hop limit for IPv6 multicast messages. This option
424 is only relevant with the IPv4 and IPv6 UDP transports. The de‐
425 fault is 1 to restrict the messages sent by ptp4l to the same
426 subnet.
427 unicast_listen
430 When enabled, this option allows the port to grant unicast mes‐
431 sage contracts. Incoming requests for will be granted limited
432 only by the amount of memory available. The default is 0 (dis‐
433 abled).
434 unicast_master_table
437 When set to a positive integer, this option specifies the table
438 id to be used for unicast discovery. Each table lives in its
439 own section and has a unique, positive numerical ID. Entries in
440 the table are a pair of transport type and protocol address.
441 The default is 0 (unicast discovery disabled).
442 unicast_req_duration
445 The service time in seconds to be requested during unicast dis‐
446 covery. Note that the remote node is free to grant a different
447 duration. The default is 3600 seconds or one hour.
448
451 asCapable
452 If set to 'true', all the checks which can unset asCapable vari‐
453 able (as described in Section 10.2.4.1 of 802.1AS) are skipped.
454 If set to 'auto', asCapable is initialized to 'false' and will
455 be set to 'true' after the relevant checks have passed. The de‐
456 fault value is 'auto'.
457 assume_two_step
460 Treat one-step responses as two-step if enabled. It is used to
461 work around buggy 802.1AS switches. The default is 0 (dis‐
462 abled).
463 BMCA This option enables use of static roles for server and client
466 devices instead of running the best master clock algorithm
467 (BMCA) described in 1588 profile. This can be used to speed up
468 the start time for servers and clients when you know the roles
469 of the devices in advance. When set to ´noop', the traditional
470 BMCA algorithm used by 1588 is skipped. masterOnly and clien‐
471 tOnly will be used to determine the server or client role for
472 the device. In a bridge, clientOnly (which is a global option)
473 can be set to make all ports assume the client role. masterOnly
474 (which is a per-port config option) can then be used to set in‐
475 dividual ports to take on the server role. The default value is
476 'ptp' which runs the BMCA related state machines.
477 check_fup_sync
480 Because of packet reordering that can occur in the network, in
481 the hardware, or in the networking stack, a follow up message
482 can appear to arrive in the application before the matching sync
483 message. As this is a normal occurrence, and the sequenceID mes‐
484 sage field ensures proper matching, the ptp4l program accepts
485 out of order packets. This option adds an additional check using
486 the software time stamps from the networking stack to verify
487 that the sync message did arrive first. This option is only use‐
488 ful if you do not trust the sequence IDs generated by the
489 server. The default is 0 (disabled).
490 clientOnly
493 The local clock is a client-only clock if enabled. The default
494 is 0 (disabled).
495 clockAccuracy
498 The clockAccuracy attribute of the local clock. It is used in
499 the PTP server selection algorithm. The default is 0xFE.
500 clockClass
503 The clockClass attribute of the local clock. It denotes the
504 traceability of the time distributed by the grandmaster clock.
505 The default is 248.
506 clock_class_threshold
509 The maximum clock class value from master, acceptible to sub-or‐
510 dinate clock beyond which it moves out of lock state. The de‐
511 fault value is 248.
512 clockIdentity
515 The clockIdentity attribute of the local clock. The clockIden‐
516 tity is an 8-octet array and should in this configuration be
517 written in textual form, see default. It should be unique since
518 it is used to identify the specific clock. If default is used
519 or if not set at all, the clockIdentity will be automtically
520 generated. The default is "000000.0000.000000"
521 clock_servo
524 The servo which is used to synchronize the local clock. Valid
525 values are "pi" for a PI controller, "linreg" for an adaptive
526 controller using linear regression, "ntpshm" and "refclock_sock"
527 for the NTP SHM and chrony SOCK reference clocks respectively to
528 allow another process to synchronize the local clock, and
529 "nullf" for a servo that always dials frequency offset zero (for
530 use in SyncE nodes). The default is "pi."
531 clock_type
534 Specifies the kind of PTP clock. Valid values are "OC" for or‐
535 dinary clock, "BC" for boundary clock, "P2P_TC" for peer to peer
536 transparent clock, and "E2E_TC" for end to end transparent
537 clock. An multi-port ordinary clock will automatically be con‐
538 figured as a boundary clock. The default is "OC".
539 dataset_comparison
542 Specifies the method to be used when comparing data sets during
543 the Best Master Clock Algorithm. The possible values are
544 "ieee1588" and "G.8275.x". The default is "ieee1588".
545 domainNumber
548 The domain attribute of the local clock. The default is 0.
549 dscp_event
552 Defines the Differentiated Services Codepoint (DSCP) to be used
553 for PTP event messages. Must be a value between 0 and 63. There
554 are several media streaming standards out there that require
555 specific values for this option. For example 46 (EF PHB) in
556 AES67 or 48 (CS6 PHB) in RAVENNA. The default is 0.
557 dscp_general
560 Defines the Differentiated Services Codepoint (DSCP) to be used
561 for PTP general messages. Must be a value between 0 and 63.
562 There are several media streaming standards out there that rec‐
563 ommend specific values for this option. For example 34 (AF41
564 PHB) in AES67 or 46 (EF PHB) in RAVENNA. The default is 0.
565 first_step_threshold
568 The maximum offset the servo will correct by changing the clock
569 frequency (phase when using nullf servo) instead of stepping the
570 clock. This is only applied on the first update. It's specified
571 in seconds. When set to 0.0, the servo won't step the clock on
572 start. The default is 0.00002 (20 microseconds). This option
573 used to be called pi_f_offset_const.
574 free_running
577 Don't adjust the local clock if enabled. The default is 0 (dis‐
578 abled).
579 freq_est_interval
582 The time interval over which is estimated the ratio of the local
583 and peer clock frequencies. It is specified as a power of two in
584 seconds. The default is 1 (2 seconds).
585 G.8275.defaultDS.localPriority
588 The Telecom Profiles (ITU-T G.8275.1 and G.8275.2) specify an
589 alternate Best Master Clock Algorithm (BMCA) with a unique data
590 set comparison algorithm. The value of this option is associ‐
591 ated with the local clock and is used as a tie breaker whenever
592 clockClass, clockAccuracy, offsetScaledLogVariance, and prior‐
593 ity2 are equal. This option is only used when "dataset_compari‐
594 son" is set to "G.8275.x". The default value is 128.
595 Warning: the BMCA is guaranteed to produce a spanning tree (that
597 is, a timing network without loops) only when using the default
598 values of G.8275.defaultDS.localPriority and G.8275.portDS.lo‐
599 calPriority. Careful network engineering is needed when using
600 non-default values.
601 gmCapable
604 If this option is enabled, then the local clock is able to be‐
605 come grand master. This is only for use with 802.1AS clocks and
606 has no effect on 1588 clocks. The default is 1 (enabled).
607 ignore_source_id
610 This will disable source port identity checking for Sync and
611 Follow_Up messages. This is useful when the announce messages
612 are disabled in the server and the client does not have any way
613 to know the server's identity. The default is 0 (disabled).
614 inhibit_announce
617 This will disable the timer for announce messages (i.e.
618 FD_MANNO_TIMER) and also the announce message timeout timer
619 (i.e. FD_ANNOUNCE_TIMER). This is used by the Automotive profile
620 as part of switching over to a static BMCA. If this option is
621 enabled, ignore_source_id has to be enabled in the client be‐
622 cause it has no way to identify the server in the Sync and Fol‐
623 low_Up messages. The default is 0 (disabled).
624 initial_delay
627 The initial path delay of the clock in nanoseconds used for syn‐
628 chronization of the clock before the delay is measured using the
629 E2E or P2P delay mechanism. If set to 0, the clock will not be
630 updated until the delay is measured. The default is 0.
631 interface_rate_tlv
634 When the client and server are operating are operating at dif‐
635 ferent interface rate, delay asymmetry caused due to different
636 interface rate needs to be compensated. The server sends its
637 interface rate using interface rate TLV as per G.8275.2 Annex D.
638 The default is 0 (does not support interface rate tlv).
639 hwts_filter
642 Select the hardware time stamp filter setting mode. Possible
643 values are normal, check, full. Normal mode set the filters as
644 needed. Check mode only check but do not set. Full mode set
645 the receive filter to mark all packets with hardware time stamp,
646 so all applications can get them. The default is normal.
647 kernel_leap
650 When a leap second is announced, let the kernel apply it by
651 stepping the clock instead of correcting the one-second offset
652 with servo, which would correct the one-second offset slowly by
653 changing the clock frequency (unless the step_threshold option
654 is set to correct such offset by stepping). Relevant only with
655 software time stamping. The default is 1 (enabled).
656 logging_level
659 The maximum logging level of messages which should be printed.
660 The default is 6 (LOG_INFO).
661 manufacturerIdentity
664 The manufacturer id which should be an OUI owned by the manufac‐
665 turer. The default is 00:00:00.
666 max_frequency
669 The maximum allowed frequency adjustment of the clock in parts
670 per billion (ppb). This is an additional limit to the maximum
671 allowed by the hardware. When set to 0, the hardware limit will
672 be used. The default is 900000000 (90%). This option used to
673 be called pi_max_frequency.
674 maxStepsRemoved
677 When using this option, if the value of stepsRemoved of an An‐
678 nounce message is greater than or equal to the value of maxStep‐
679 sRemoved the Announce message is not considered in the operation
680 of the BMCA. The default value is 255.
681 message_tag
684 The tag which is added to all messages printed to the standard
685 output or system log. The default is an empty string (which
686 cannot be set in the configuration file as the option requires
687 an argument).
688 msg_interval_request
691 This option, when set, will trigger an adjustment to the Sync
692 and peer delay request message intervals when the clock servo
693 transitions into the SERVO_LOCKED_STABLE state. The Sync inter‐
694 val will be adjusted via the signaling mechanism while the pde‐
695 lay request interval is simply adjusted locally. The values to
696 use for the new Sync and peer delay request intervals are speci‐
697 fied by the operLogSyncInterval and operLogPdelayReqInterval op‐
698 tions, respectively. The default value of msg_interval_request
699 is 0 (disabled).
700 ntpshm_segment
703 The number of the SHM segment used by ntpshm servo. The default
704 is 0.
705 offsetScaledLogVariance
708 The offsetScaledLogVariance attribute of the local clock. It
709 characterizes the stability of the clock. The default is
710 0xFFFF.
711 pi_integral_const
714 The integral constant of the PI controller. When set to 0.0, the
715 integral constant will be set by the following formula from the
716 current sync interval. The default is 0.0.
717 ki = min(ki_scale * sync^ki_exponent, ki_norm_max / sync)
719 pi_integral_exponent
722 The ki_exponent constant in the formula used to set the integral
723 constant of the PI controller from the sync interval. The de‐
724 fault is 0.4.
725 pi_integral_norm_max
728 The ki_norm_max constant in the formula used to set the integral
729 constant of the PI controller from the sync interval. The de‐
730 fault is 0.3.
731 pi_integral_scale
734 The ki_scale constant in the formula used to set the integral
735 constant of the PI controller from the sync interval. When set
736 to 0.0, the value will be selected from 0.3 and 0.001 for the
737 hardware and software time stamping respectively. The default
738 is 0.0.
739 pi_proportional_const
742 The proportional constant of the PI controller. When set to 0.0,
743 the proportional constant will be set by the following formula
744 from the current sync interval. The default is 0.0.
745 kp = min(kp_scale * sync^kp_exponent, kp_norm_max / sync)
747 pi_proportional_exponent
750 The kp_exponent constant in the formula used to set the propor‐
751 tional constant of the PI controller from the sync interval.
752 The default is -0.3.
753 pi_proportional_norm_max
756 The kp_norm_max constant in the formula used to set the propor‐
757 tional constant of the PI controller from the sync interval.
758 The default is 0.7
759 pi_proportional_scale
762 The kp_scale constant in the formula used to set the propor‐
763 tional constant of the PI controller from the sync interval.
764 When set to 0.0, the value will be selected from 0.7 and 0.1 for
765 the hardware and software time stamping respectively. The de‐
766 fault is 0.0.
767 productDescription
770 The product description string. Allowed values must be of the
771 form manufacturerName;modelNumber;instanceIdentifier and contain
772 at most 64 utf8 symbols. The default is ";;".
773 priority1
776 The priority1 attribute of the local clock. It is used in the
777 PTP server selection algorithm, lower values take precedence.
778 Must be in the range 0 to 255. The default is 128.
779 priority2
782 The priority2 attribute of the local clock. It is used in the
783 PTP server selection algorithm, lower values take precedence.
784 Must be in the range 0 to 255. The default is 128.
785 refclock_sock_address
788 The address of the UNIX domain socket to be used by the ref‐
789 clock_sock servo. The default is /var/run/refclock.ptp.sock.
790 revisionData
793 The revision description string which contains the revisions for
794 node hardware (HW), firmware (FW), and software (SW). Allowed
795 values are of the form HW;FW;SW and contain at most 32 utf8 sym‐
796 bols. The default is an ";;".
797 sanity_freq_limit
800 The maximum allowed frequency offset between uncorrected clock
801 and the system monotonic clock in parts per billion (ppb). This
802 is used as a sanity check of the synchronized clock. When a
803 larger offset is measured, a warning message will be printed and
804 the servo will be reset. If the frequency correction set by
805 ptp4l changes unexpectedly between updates of the clock (e.g.
806 due to another process trying to control the clock), a warning
807 message will be printed. When set to 0, the sanity check is dis‐
808 abled. The default is 200000000 (20%).
809 servo_num_offset_values
812 The number of offset values considered in order to transition
813 from the SERVO_LOCKED to the SERVO_LOCKED_STABLE state. The
814 transition occurs once the last 'servo_num_offset_values' off‐
815 sets are all below the 'servo_offset_threshold' value. The de‐
816 fault value is 10.
817 servo_offset_threshold
820 The offset threshold used in order to transition from the
821 SERVO_LOCKED to the SERVO_LOCKED_STABLE state. The transition
822 occurs once the last 'servo_num_offset_values' offsets are all
823 below the threshold value. The default value of offset_thresh‐
824 old is 0 (disabled).
825 slave_event_monitor
828 Specifies the address of a UNIX domain socket for event monitor‐
829 ing. A local monitoring client bound to this address will re‐
830 ceive SLAVE_RX_SYNC_TIMING_DATA and SLAVE_DELAY_TIMING_DATA_NP
831 TLVs. The default is the empty string (disabled).
832 slaveOnly
835 This option is deprecated and will be removed in a future re‐
836 lease. Use "clientOnly" instead.
837 socket_priority
840 Configure the SO_PRIORITY of sockets. This is to support cases
841 where a user wants to route ptp4l traffic using Linux qdiscs for
842 the purpose of traffic shaping. This option is only available
843 with the IEEE 802.3 transport (the -2 option) and is silently
844 ignored when using the UDP IPv4/6 network transports. Must be in
845 the range of 0 to 15, inclusive. The default is 0.
846 step_threshold
849 The maximum offset the servo will correct by changing the clock
850 frequency (phase when using nullf servo) instead of stepping the
851 clock. When set to 0.0, the servo will never step the clock ex‐
852 cept on start. It's specified in seconds. The default is 0.0.
853 This option used to be called pi_offset_const.
854 step_window
857 When set, indicates the number of Sync events after a clock step
858 that the clock will not do any frequency or step adjustments.
859 This is used in situations where clock stepping is unable to
860 happen instantaneously so there is a lag before the timestamps
861 can settle properly to reflect the clock step. The default is 0
862 (disabled).
863 summary_interval
866 The time interval in which are printed summary statistics of the
867 clock. It is specified as a power of two in seconds. The statis‐
868 tics include offset root mean square (RMS), maximum absolute
869 offset, frequency offset mean and standard deviation, and path
870 delay mean and standard deviation. The units are nanoseconds and
871 parts per billion (ppb). If there is only one clock update in
872 the interval, the sample will be printed instead of the statis‐
873 tics. The messages are printed at the LOG_INFO level. The de‐
874 fault is 0 (1 second).
875 tc_spanning_tree
878 When running as a Transparent Clock, increment the "stepsRe‐
879 moved" field of Announce messages that pass through the switch.
880 Enabling this option ensures that PTP message loops never form,
881 provided the switches all implement this option together with
882 the BMCA.
883 timeSource
886 The time source is a single byte code that gives an idea of the
887 kind of local clock in use. The value is purely informational,
888 having no effect on the outcome of the Best Master Clock algo‐
889 rithm, and is advertised when the clock becomes grand master.
890 time_stamping
893 The time stamping method to be used. The allowed values are
894 hardware, software, legacy, onestep, and p2p1step. The default
895 is hardware.
896 twoStepFlag
899 Enable two-step mode for sync messages. One-step mode can be
900 used only with hardware time stamping. The default is 1 (en‐
901 abled).
902 tx_timestamp_timeout
905 The number of milliseconds to poll waiting for the tx time stamp
906 from the kernel when a message has recently been sent. The de‐
907 fault is 10.
908 udp6_scope
911 Specifies the desired scope for the IPv6 multicast messages.
912 This will be used as the second byte of the primary address.
913 This option is only relevant with IPv6 transport. See RFC 4291.
914 The default is 0x0E for the global scope.
915 uds_address
918 Specifies the address of the UNIX domain socket for receiving
919 local management messages. The default is /var/run/ptp4l.
920 uds_file_mode
923 File mode of the UNIX domain socket used for receiving local
924 management messages. The mode should be specified as an octal
925 number, i.e. it should start with a 0 literal. The default mode
926 is 0660.
927 uds_ro_address
930 Specifies the address of the second UNIX domain socket for re‐
931 ceiving local management messages, which is restricted to GET
932 actions and does not forward messages to other ports. Access to
933 this socket can be given to untrusted applications for monitor‐
934 ing purposes. The default is /var/run/ptp4lro.
935 uds_ro_file_mode
938 File mode of the second (read-only) UNIX domain socket used for
939 receiving local management messages. The mode should be speci‐
940 fied as an octal number, i.e. it should start with a 0 literal.
941 The default mode is 0666.
942 use_syslog
945 Print messages to the system log if enabled. The default is 1
946 (enabled).
947 userDescription
950 The user description string. Allowed values are of the form
951 name;location and contain at most 128 utf8 symbols. The default
952 is an empty string.
953 utc_offset
956 The current offset between TAI and UTC. The default is 37.
957 verbose
960 Print messages to the standard output if enabled. The default
961 is 0 (disabled).
962 write_phase_mode
965 This option enables using the "write phase" feature of a PTP
966 Hardware Clock. If supported by the device, this mode uses the
967 hardware's built in phase offset control instead of frequency
968 offset control. The default value is 0 (disabled).
969
972 L2|UDPv4|UDPv6
973 Each table entry specifies the transport type and network ad‐
974 dress of a potential remote server. If multiple servers are
975 specified, then unicast negotiation will be performed with each
976 if them.
977 logQueryInterval
980 This option configures the time to wait between unicast negotia‐
981 tion attempts. It is specified as a power of two in seconds.
982 The default is 0 (1 second).
983 peer_address
986 This option specifies the unicast address of the peer for use
987 with the peer to peer delay mechanism. If specified, the port
988 owning the table will negotiate unicast peer delay responses
989 from the machine at the given remote address, otherwise the port
990 will send multicast peer delay requests.
991 table_id
994 Each table must begin with a unique, positive table ID. The
995 port that claims a given table does so by including the ID as
996 the value of its 'unicast_master_table' option.
997
1000 When ptp4l acts as the domain server, it either uses the PTP or the UTC
1001 time scale depending on time stamping mode. In software and legacy
1002 time stamping modes it announces Arbitrary time scale mode, which is
1003 effectively UTC here. In hardware time stamping mode it announces use
1004 of PTP time scale.
1005 When ptp4l is the domain server using hardware time stamping, it is up
1007 to phc2sys to maintain the correct offset between UTC and PTP times.
1008 See phc2sys(8) manual page for more details.
1009
1012 pmc(8), phc2sys(8)
1013linuxptp February 2023 PTP4l(8)