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Precision Time Protocol is used to synchronize clocks throughout the network. On a local area network, it achieves clock accuracy in the sub-microsecond range, making it suitable for measurement and control systems. RouterOS supports IEEE 1588-2008, PTPv2. Support is hardware dependant and currently, only select CRS3xx models support it, please see the supported device list below.
Supported features:
- Boundary/Ordinary clock
- E2E delay mode
- PTP delay mode
- UDP over IPv4 multicast transport mode
- runs in domain 0L2 transport mode
- priority1 can be configured to decide master/slave
- PTP clock IS NOT synced with the system clock
General properties
Sub-menu: /system ptp
| Property | Description |
|---|---|
| port | Sub-menu used for adding, removing, or viewing assigned ports |
| status | Sub-menu that shows PTP ports, their state, and delay on slave ports |
| comment (string; Default: ) | Short description of the PTP profile |
| name (string; Default: ) | Name of the PTP profile |
| delay-mode (auto | e2e | ptp; Default: auto) | Configures delay mode for PTP profile
|
| priority1 (integer [0..255]; auto; Default:auto) | the priority value for influencing grandmaster election |
| profile (802.1as; default; g8275.1; Default: default) | IEEE 1588-2008 includes a profile concept defining PTP operating parameters and options. IEEE 802.1AS is an adaptation of PTP for use with Audio Video Bridging and Time-Sensitive Networking. Uses delay-mode=p2p, transport-mode=l2; recommends using priority1=auto. g8275.1 profile is for frequency and phase synchronization in a fully PTP-aware network. Only allows priority1=auto (128), priority2=128, domain=24, delay-mode=e2e, transport=l2. default profile, PTPv2 default configuration, allows for more configuration options than other profiles, but default values with auto settings correspond to: priority1=128. priority2=128, domain=0,transport=ipv4, delay-mode=e2e |
| transport (auto; ipv4; l2; Default: auto) | transport protocol to be used: IPv4 or layer2 |
| Info |
|---|
For more details regarding Precision Time Protocol please see the following standards IEEE 1588 and IEEE 802.1as. |
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#on grandmaster device [admin@grandmaster] > system ptp monitor numbers=0 name: test clock-id: 64:D1:54:FF:FE:EB:AE:C3 priority1: 30 priority2: 128 i-am-gm: yes #on non-grandmaster device [admin@328] /system ptp monitor 0 name: ptp1 clock-id: 64:D1:54:FF:FE:EB:AD:C7 priority1: 128 priority2: 128 i-am-gm: no gm-clock-id: 64:D1:54:FF:FE:EB:AE:C3 gm-priority1: 30 gm-priority2: 128 master-clock-id: 64:D1:54:FF:FE:EB:AE:C3 slave-port: ether8 freq-drift: 2147483647 ppb offset: 1396202830 ns hw-offset: 1306201921 ns slave-port-delay: 2075668440 ns |
Monitor properties
| Property | Description |
|---|---|
| clock-id: | local clock ID |
| priority1: | priority1 value, depending on the PTP profile selected, an adjustable value |
| used to influence the grandmaster election. | |
| priority2: | priority2 value, non-adjustable in RouterOS |
| i-am-gm: yes | no | shows if the device is a grandmaster clock |
| gm-clock-id: | grandmaster clock ID - Within a domain, a clock that is the ultimate source of time for clock synchronization using the protocol. |
| gm-priority1: | grandmaster priority1 |
| gm-priority2: | grandmaster priority2 |
| master-clock-id: | master clock ID - In the context of a single Precision Time Protocol (PTP) communication path, a clock that is the source of time to which all other clocks on that path synchronize. |
| slave-port: | shows which port is going towards the master or grandmaster clock |
| freq-drift: | frequency drift in PPB (parts per billion) - time that would be lost every second in relation to the master clock, IF there was no synchronization. |
| offset: | difference between clock values |
| hw-offset: | offset difference from the hardware clock |
| slave-port-delay: | the time it takes for a packet to be delivered to a directly connected device |
Device support
Note: devices not included in the list below, does not support Precision Time Protocol
Supported on:
- CRS326-24G-2S+ supported only on Gigabit Ethernet ports
- CRS328-24P-4S+ supported only on Gigabit Ethernet ports
- CRS317-1G-16S+ supported on all ports
- CRS326-24S+2Q+ supported on SFP+ and QSFP+ interfaces
- CRS312-4C+8XG supported on all ports
- CRS318-16P-2S+
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- supported
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- only on Gigabit Ethernet ports