TCP/IP Management Programming Manual

Management Programming

HP NonStop TCP/IP Management Programming Manual—529636-001

2-6

Event Messages

An event message describes an anomaly that has occurred in a subsystem, such as a

hardware or software error. All event messages are in an SPI message format.

All event messages issued by the TCP/IP subsystem are sent to the EMS collector

process ($0). These event messages are then placed into the user-specified log files.

Once placed into the log files, the EMS consumer distributor process can read the

event messages and retrieve the selected events for the management application.

A management application retrieves event messages by sending commands in an SPI

message format to an EMS consumer distributor. To select event messages, you can

write a filter that is specific to your needs. If no filter is used, all event messages in the

log file are passed to the management application by the consumer distributor.

Figure 2-1 on page 2-3 illustrates the flow of data between the TCP/IP subsystem and

a management application in the EMS environment. Note that event messages can

also be retrieved interactively through the ViewPoint console application. For further

details on the ViewPoint application, see the ViewPoint Manual.

For detailed descriptions of event messages and event management as they relate to

the TCP/IP subsystem, see Section 7, Event Management. For a description of event

messages and event management in general, see the EMS Manual.

Communicating With the TCP/IP Subsystem

A management application communicates with the TCP/IP subsystem by means of the

SCP or the EMS consumer distributor process. When communicating with the SCP or

the EMS, an application calls SPI procedures to build messages to be sent to the

subsystem and to retrieve messages sent from the subsystem. However, to send and

receive SPI messages, and to establish and terminate communication with the SCP or

the EMS distributor process, an application must use the NonStop operating system.

How you use the file system depends on the language in which your application is

written. If your application is written in TAL or C, you use the file-system procedures

directly to send and receive the SPI messages. If your application is written in COBOL

(COBOL 74 does not support SPI), you use the file-system procedures indirectly by

invoking them through COBOL85 verbs. If your application is written in TACL, you use

the file-system procedures indirectly by invoking them through TACL built-ins.

Regardless of the language you are using, the tasks an application must perform when

communicating with either the SCP or the EMS distributor process are:

1. Establish communication with the SCP or the EMS distributor process.

2. Call SPI procedures to build a message.

3. Send the message to the SCP or the EMS distributor process.

4. Receive the response.