Symmetricom Time Server Manual Do Utilizador

Página de 148
6000-100AppD.fm  Rev. D
TimeVault™ User’s Manual
D-111
Symmetricom SNMP Enterprise MIB
Appendix D: SNMP – Simple Network Management Protocol
The trap message group holds the ASCII string data to send whenever an SNMP trap 
message is transmitted.  The NTS agent sends SNMP trap messages to SNMP 
management hosts notifying them of some critical event at the NTS agent.  The NTS 
issues three types of trap messages.  The first type is a cold start trap message indicating 
when the box boots or re-initializes.  The second type of trap message is issued when the 
NTS estimated time error has exceeded the minimum time accuracy threshold.  The third 
trap message is issued when a packet received by the NTS agent fails SNMP 
authentication.  The second feature notifies a network administrator immediately if the 
time server lost its ability to tell accurate time.
The NTP Enterprise Group furnishes information on the Network Time Protocol.  This 
group provides packet information for the number of received, rejected, and transmitted 
NTP packets exchanged between the UDP transport and the NTP application layers.  
Packets are rejected when they are malformed or the MD5 encryption authentication 
failed.  In addition, time quality can be assessed by looking at the current estimated time 
error and comparing it with the time accuracy threshold.  Finally, all of the NTP control 
information transmitted by the NTS in an NTP packet is available in this enterprise group.  
One important variable in this group is ntpSysLeap because it is the clearest indication if 
the NTS is telling correct time.
When GPS is used as the time synchronization source, the GPS Enterprise MIB Group 
provides detailed information about the satellites used by the NTS.  Complete GPS 
satellite information exists on the number of satellites tracked and used for timing 
purposes, their signal strengths, the tracking mode, altitude, longitude, and latitude of the 
GPS antenna.  This information allows you to properly set up the GPS antenna and to use 
the unit for time information.
When ACTS is used as the time synchronization source (see Appendix E for details), the 
ACTS Enterprise MIB Group provides detailed information on the ACTS dial-up modem 
time service.  Complete information on the number and success of the ACTS phone calls 
as well as a detailed break down of the various possible modem and line failures that can 
occur.  This information allows you to fine tune calling frequency with the desired time 
accuracy and assess the telephone line quality of the connection to the ACTS service.
Obtaining the enterprise MIB information requires you to have an SNMP management 
program running on your computer.
Variable Definitions
This section contains a complete and formal definition of Symmetricom’s SNMP 
enterprise MIB group, including all the variables in Symmetricom's Enterprise MIB, along 
with the MIB OID address and data types.  
An electronic form of this file was included with this manual.  If the disk has been 
misplaced or corrupted, a copy can be obtained from Symmetricom’s web site 
(www.truetime.net).  Select Products and Literature>Reference Material to get there.  
The file’s name is “TrueTime.MIB”, and should compile for virtually any SNMP 
management software.  It has been verified to work for Sun’s Solaris X-SNMP and 
Hewlett Packard’s OpenView management software packages.