Summary
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.
Supported features:
- Boundary/Ordinary clock
- E2E mode
- UDP over IPv4 multicast mode
- runs in domain 0
- 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, |
For more details regarding Precision Time Protocol please see the following standards IEEE 1588 and IEEE 802.1as.
We strongly recommend keeping default/auto values, as there are different requirements between profiles. And assigning them manually can result in misconfiguration.
Configuration
To configure the device to participate in PTP you first need to create a PTP profile:
/system ptp add name=ptp1 #to view the created profile use /system ptp print Flags: I - inactive, X - disabled 0 name="ptp1" priority1=auto delay-mode=auto transport=auto profile=default
Note
Only 1 PTP profile is supported per device
After creating a PTP profile, you need to assign ports to it:
/system ptp port add interface=ether1 ptp=ptp1 #to view assigned ports use /system ptp port print Flags: I - inactive 0 ptp=ptp1 interface=ether8 1 ptp=ptp1 interface=ether22
To monitor the PTP profile, use the monitor command:
#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, adjustable value in profile settings |
| 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 |
| gm-priority1: | grandmaster priority1 |
| gm-priority2: | grandmaster priority2 |
| master-clock-id: | master clock ID |
| 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. |
Device support
Supported on:
CRS326-24G-2S+
CRS328-24P-4S+
CRS317-1G-16S+
CRS326-24S+2Q+
CRS312-4C+8XG
CRS318-16P-2S+
Not supported on:
CRS305-1G-4S+
CRS309-1G-8S+
CRS328-4C-20S-4S+
CRS354-48G-4S+2Q+