One system needs network information from another system:
The NMQ (Network Management Query) message is used by one system to make system-level requests for information or action to another system. It has three segments, the NCK segment (network clock), the NST segment (network statistics), and the NSC segment (network status change). An example of the last type, NSC (network status change) would be an application or system startup/shut down request. At least one of these three segments must be present in the NMQ message. If a segment is present in the NMQ message, the corresponding segment needs to be present in the NMR message to return the requested data or status.
a) The purpose of the NCK segment is to allow the various systems on the network to synchronize their system clocks (system date and time).
b) The purpose of the NST segment is to allow network statistical information to be passed between the various systems on the network. Although some of the fields in this segment refer to portions of lower level protocols, they contain information that can be used be network management applications monitoring the state of various network links. All the data fields in the NST (network statistics) are optional, and the fields maintained by any system are to be negotiated at a particular site.
c) The NSC segment can be used to request the start-up, shut-down, and/or migration (to a different CPU or file-server/file-system) of a particular application. It can also be used in an unsolicited update from one system to another to announce the start-up, shut-down, or migration of an application.
Chapter/
NMQ Network Management Query Appendix
MSH Message Header 2
[QRD Query Definition 2
[QRF]] Query Filter 2
{[NCK] Network System Clock C
[NST] Network Statistics C
[NSC]} Network Status Change C
Chapter/
NMR Network Management Response Appendix
MSH Message Header 2
MSA Message Acknowledgement 2
[ERR] Error 2
[QRD] Query Definition 2
{[NCK] System Clock C
[{NTE}] Notes and Comments 2
[NST] Statistics C
[{NTE}] Notes and Comments 2
[NSC] Network Status Change C
[{NTE}] } Notes and Comments 2