Netgear M5300-28G-POE+ (GSM7228PSv1h2) - 12-Port Managed Gigabit Switch Softwarehandbuch

SNTP assures accurate network device clock time synchronization up to the millisecond. 
Time synchronization is performed by a network SNTP server. M6100/M7100/M5300 
software operates only as an SNTP client and cannot provide time services to other systems.

Time sources are established by stratums. Stratums define the accuracy of the reference 
clock. The higher the stratum (where zero is the highest), the more accurate the clock. The 
device receives time from Stratum 1 and above since it is itself a Stratum 2 device. 

The following is an example of stratums: 

. A real-time clock is used as the time source, for example, a GPS system. 

. A server that is directly linked to a Stratum 0 time source is used. Stratum 1 

time servers provide primary network time standards. 

. The time source is distanced from the Stratum 1 server over a network path. 

For example, a Stratum 2 server receives the time over a network link, through NTP, from 
a Stratum 1 server.

Information received from SNTP servers is evaluated based on the time level and server 
type.

SNTP time definitions are assessed and determined by the following time levels: 

. Time that the original request was sent by the client.

. Time that the original request was received by the server.

. Time that the server sent a reply.

. Time that the client received the server's reply.

The device can poll unicast server types for the server time.

Polling for unicast information is used for polling a server for which the IP address is known. 
SNTP servers that were configured on the device are the only ones that are polled for 
synchronization information. T1 through T4 are used to determine server time. This is the 
preferred method for synchronizing device time because it is the most secure method. If this 
method is selected, SNTP information is accepted only from SNTP servers defined on the 
device using the SNTP Server Configuration screen.

The device retrieves synchronization information, either by actively requesting information or 
at every poll interval.

You can view and modify information for adding and modifying Simple Network Time Protocol 
SNTP servers.



Prepare your computer with a static IP address in the 169.254.100.0 subnet, for 

example, 169.254.100.201.

Connect an Ethernet cable from an Ethernet port on your computer to an Ethernet port on 

the switch.

Launch a web browser.