Dell PowerConnect 5548 User Guide - Page 171

SNTP Overview The switch supports the Simple Network Time Protocol (SNTP), which provides accurate network switch clock time synchronization of up to 100 milliseconds. The implementation of SNTP is based on SNTPv4 (RFC 2030). SNTP is a simple and lighter version of NTP, and can be used when the ultimate performance of the full NTP implementation, described in RFC-1305, is not required. SNTP operates with NTP, thus an SNTP client can work with both SNTP and NTP servers. The switch operates only as a client, and cannot provide time services to other systems. SNTP Server Types The switch can accept time information from the following server types: • Unicast Polling for Unicast information is used for polling a server whose IP address is known. This is the preferred method for synchronizing device time, as it is most secure. Up to eight SNTP servers can be defined. If this method is selected, SNTP information is accepted only from SNTP servers defined in the SNTP Servers page. Time levels T1 - T4 (see the "Algorithm for Selecting Designated SNTP Server" on page 173 section) are used to determine from which server time information is accepted. If Unicast polling is not enabled or if no servers are defined on the device, the device accepts time information from any SNTP server of the type that is enabled, which responds. • Anycast Polling for Anycast information is used when the SNTP server's IP address is not defined or it cannot be reached. If this method is enabled, time information can be received from any SNTP server on the network. The Dell PowerConnect 55xx Systems User Guide 171