Applications
Simple Network Time Protocol (SNTP)
The Simple Network Time Protocol (SNTP) feature on the Perle Routers support the client side of the protocol as described in RFC 2030. The router will be able to obtain its time from a NTP or SNTP server and then can be synchronized amongst other network devices. Additionally, the router can also be configured to support various time variations features such as local time zone and adjustments for daylight savings time.
When the Perle router has SNTP enabled it will periodically send NTP packets to the NTP/SNTP server which will respond with the network time. The router will synchronize its internal clock with the response from the NTP/SNTP server. The method in which the router sends or receives the NTP packets from the NTP/SNTP server is configurable in three modes: unicast, multicast and anycast.
In unicast mode, the router will have to be configured with the IP Address of the NTP server and will periodically send a request packet to the NTP server. The NTP server will then respond directly to this request with the current time. The Perle router supports a primary and a secondary IP Address for NTP servers.
In multicast mode, the router does not initiate the request packets but waits to receive the periodic broadcasts from the NTP server with the current time. Once the router receives an NTP packet from the server, it will then synchronize its internal clock with the current time.
In anycast mode, the router will send out a request packet as a broadcast on the LAN to get a response from any NTP server. When the first response is received from an NTP server, the internal clock of the router is synchronized. The router will learn the IP Address of the NTP server that responded and then operate in unicast mode.
The Perle router supports time variation feature of local time zones and daylight savings time regardless if the internal clock is synchronized with an NTP server. The local time zone feature allows the router to offset the internal clock by a configurable time from the UTC time. The configurable time zone off set can be specified in hours (0 to 23) and minutes (0 to 59) and can also be specified by a specific name up to 4 characters.
Adjustments to the internal clock for daylight saving time
To enable SNTP on the router and setup for unicast mode to directly obtain the time from a specific NTP server implement the following steps.
Location:
ªConfiguration ªApplication
ªSNTP
ªenable
ªMode ªunicast
ªPrimary IP Address
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