Chapter 1: General Information

Network Time Protocol Synchronization Specifications

1.11Network Time Protocol Synchronization Specifications

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.

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TimeVault™ User’s Manual

6000-100Ch1.fm Rev. D

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Symmetricom Time Server user manual Network Time Protocol Synchronization Specifications