Symmetricom Time Server Manual Do Utilizador

Chapter 1: General Information

TimeVault’s hardware is specifically designed to implement the NTP server function.  As 
such, it was carefully designed to minimize the unknown latencies in timestamping 
received and transmitted NTP packets.  The NTP timestamp accuracy specifications are:

Received Timestamp Accuracy:

<0.1 ms, relative to synchronization source

Transmitted Timestamp Accuracy: <0.1 ms, relative to synchronization source

At these levels, the realizable NTP synchronization accuracy of any host is determined by 
the repeatability of network and client delays, not by TimeVault’s timestamp uncertainty.

TimeVault supports the following protocols:

• Telnet  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-854

• DAYTIME 

(available in TCP and UDP protocols)

 . . . . . . . . .RFC-867

• TIME 

(available in TCP and UDP protocols)

 . . . . . . . . . . . . .RFC-868

• FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-959

• SMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-1155

• SNMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-1157

• MIB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-1212

• MIB II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-1213

• NTP ver. 4.0  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N/A

(backwards compatible with NTP ver.2, RFC-1119, and ver.3, RFC-1305**)

• MD5  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-1321

• SNTP  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-2030

• HTTP  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-2068 and 2616

• DHCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RFC-2132

* SMI = Structure of Management Information

** TimeVault does not implement the “authenticator field” of the NTP packet as 

described in Appendix C of RFC-1305.

Complete RFC information is available at http://www.ietf.org/

An NTP or SNTP client, compatible with the computer platform you use and configured 
to use TimeVault’s NET Port IP address, is required for accurate network 
synchronization.  In this manual, refer to Appendix A and Appendix B for details about 
NTP and SNTP protocols, and Appendix D for details about SNMP and MIB.

Note: A number of  NTP-related programs, such as NTPDC and  NTPQ, are not 
supported, in the conventional sense, by Dr. Mills’ NTP, and therefore cannot be 
supported by Symmetricom, Inc. (TrueTime, Inc. is now Symmetricom, Inc.).  The user of 
these programs does so at his or her own risk.