ptp min-delayreq-interval

Function

The ptp min-delayreq-interval command sets the minimum interval for sending Delay_Req messages on a 1588v2 interface.

The undo ptp min-delayreq-interval command restores the default minimum interval for sending Delay_Req messages on a 1588v2 interface.

By default, the minimum interval for sending 1588v2 Delay_Req messages on a 1588v2 interface is 128 ms, and the minimum interval for sending G.8275.1 Delay_Req messages on a 1588v2 interface is 64 ms.

Format

ptp min-delayreq-interval min-delayreq-interval

undo ptp min-delayreq-interval

Parameters

Parameter	Description	Value
min-delayreq-interval	Specifies that the minimum interval for sending Delay_Req messages on a 1588v2 interface is set to the min-pdelayreq-intervalth power of 2, in milliseconds.	The value is an integer that ranges from 0 to 20. In 1588v2 mode, the default value is 7, namely, 128 ms. In G.8275.1 mode, the default value is 6, namely, 64 ms. Table 1 shows the mapping between the min-delayreq-interval value and the actual sending interval.

**Table 1** Mapping between the *min-delayreq-interval* value and the actual sending interval
Value of min-delayreq-interval	Actual Interval
0	1 ms
1	2 ms
2	4 ms
3	8 ms
4	16 ms
5	32 ms
6	64 ms
7	128 ms
8	256 ms
9	512 ms
10	1s
11	2s
12	4s
13	8s
14	16s
15	32s
16	64s
17	128s
18	256s
19	512s
20	1024s

Views

XGE interface view, 25GE interface view, 40GE interface view, 100GE interface view

Default Level

2: Configuration level

Usage Guidelines

During 1588v2 clock synchronization, an Announce message is sent to determine the master-slave hierarchy, where the upstream node that advertises the synchronization time is the master device and the downstream node that receives the synchronization time is called the slave device. The master device sends Sync messages to the slave device to transmit performance parameters of time signals. In addition, the delay measurement mechanism can be implemented to ensure the accuracy of time signals.

Because the delay varies according to the network link, the 1588v2 time signals may be inaccurate. During 1588v2 clock synchronization, delay and Pdelay messages are transmitted to measure link delay, and time signals can be corrected based on the link delay. During the delay measurement request process, the local device sends a Delay_Req message and the peer device replies with a Delay_Resp message. There are two types of delay measurement mechanism.

delay: specifies a delay request-response mechanism, in which information about the clock and time is calculated according to the delay of the entire link between the PTP device and the clock source. In this mode, the slave device sends a Delay_Req message to the master device, and the slave device corrects time signals based on the Delay_Resp message replied by the master device.
pdelay: specifies a peer delay mechanism, in which information about the time and clock is calculated according to the delay of each segment of the link between the PTP device and the clock source. In this mode, the slave device and master device exchange Pdelay_Req messages and time signals are corrected based on the Pdelay_Resq messages replied.

If min-delayreq-interval is set to a small value, PTP devices frequently exchange Delay_Req messages, occupying many bandwidth resources. If min-delayreq-interval is set to a large value, high-precision clock synchronization cannot be guaranteed. If the required clock synchronization accuracy is guaranteed, set min-delayreq-interval to a large value.

Example

# Set the minimum interval for sending Delay_Req messages on the 1588v2 interface XGigabitEthernet 0/0/1 to 256 ms.

<HUAWEI> system-view
[HUAWEI] interface xgigabitethernet 0/0/1
[HUAWEI-XGigabitEthernet0/0/1] ptp min-delayreq-interval 8