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H3C Technologies H3C WX3000E Series Wireless Switches User Manual

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11

NOTE:

All NTP messages mentioned in this document refer to NTP clock synchronization messages.

A clock synchronization message is encapsulated in a UDP message, in the format shown in

Figure 6

.

Figure 6 Clock synchronization message format

Main fields are described as follows:

LI (Leap Indicator)—A 2-bit leap indicator. If set to 11, it warns of an alarm condition (clock
unsynchronized). If set to any other value, it is not to be processed by NTP.

VN (Version Number)—A 3-bit version number that indicates the version of NTP. The latest version
is version 4.

Mode—A 3-bit code that indicates the work mode of NTP. This field can be set to these values:

{

0—Reserved

{

1—Symmetric active

{

2—Symmetric passive

{

3—Client

{

4—Server

{

5—Broadcast or multicast

{

6—NTP control message

{

7—Reserved for private use

Stratum—An 8-bit integer that indicates the stratum level of the local clock, taking the value of 1 to
16. Clock precision decreases from stratum 1 through stratum 16. A stratum 1 clock has the highest
precision, and a stratum 16 clock is not synchronized.

Poll—An 8-bit signed integer that indicates the maximum interval between successive messages,
which is called the poll interval.

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