MSR G2 NTP时钟偏移量容忍度

Q：MSR G2 NTP时钟偏移量容忍度？

A：容忍的时钟偏移量为128ms， 与时钟层数无关。当设备检测到时钟偏移量超过128ms会进行时钟step并打印日志，另外还有2个约束条件。 

1.ntp每次会话都会采集样本，一共保留8个样本，每次只会有一个选中的样本，只有选中的样本超过128ms才算是检测到128ms以上误差 

2.两次step之间有10分钟的step抑制， 即刚刚发生过时钟step，又很快检测到了128ms的时钟偏移，也不会立即同步。 

*Oct 10 12:13:29:782 2018 H3C NTP/7/SELECT: Clock update at 768, sample 427, session ID 4375, offset -0.018106 

display ntp sessions verbose 

Clock source: 1.1.1.1

Session ID: 56318

Clock stratum: 2   

 Clock status:  configured, master, sane, valid

Reference clock ID: 1.1.1.1

VPN instance: Not specified

Local mode: client, local poll interval: 6

Peer mode: server, peer poll interval: 6

Offset: -137.2ms, roundtrip delay: 1.4953ms, dispersion: 5.0659ms

Root roundtrip delay: 0.8392ms, root dispersion: 21.881ms

Reachabilities:255, sync distance: 0.0368

Precision: 2^-20, version: 4, source interface: Not specified

Reftime: df4832c5.d0c6822f  Sun, Sep 16 2018  9:39:17.815

Orgtime: df48331e.456e6802  Sun, Sep 16 2018  9:40:46.271

Rcvtime: df48331e.1ecb4289  Sun, Sep 16 2018  9:40:46.120

Xmttime: df48331e.1ecb4289  Sun, Sep 16 2018  9:40:46.120

Roundtrip delay samples: 1.510 1.510 1.510 1.510 1.541 1.510 1.495 1.495

Offset samples: -151.69 -148.21 -145.12 -142.46 -140.18 -138.50 -137.24 -136.01

Filter order: 6     7     0     1     3     2     5     4