DSAP Considerations
The DSAP parameter identifies a program or process for which a packet is intended. If this command is sent to a program or process, that routine must be able to recognize the received TEST command packet, and return a TEST response packet.
The Node Manager software on each HP 1000 node utilizes SAP F8 hex, and is able to properly respond. Also, each LANIC card contains firmware that responds to the special Null SAP 00 (the driver and system software are not accessed).
If a DSAP is specified for which there is no program or process, the TEST packet is treated as an orphan packet (see Chapter 4).
Self%Addressed TEST Packets
When the ADR address (specified or defaulted) identifies the same LANIC card as the LU# parameter, the command is •self"addressed". For self"addressed TEST commands, a warning message is issued, and the command is executed as follows:
1.A self"addressed TEST command issued to DSAP=F8 hex is a software loopback. The Node Manager software from which the command was issued processes the command and issues a response; the packet is never sent to the LANIC card.
2.A self"addressed TEST command issued to any DSAP other than F8 is transmitted on the Link and transparently looped back by the card at the same time. If no process is waiting on this particular DSAP to receive this packet, it will be treated as an orphan packet.
Errors
Command entry errors resulting from TEST commands are the same as for other Node Manager commands. On the other hand, command execution errors (such as driver errors) resulting from the TEST command are not returned to the user; they are returned to system LU 1 (system console) of the node whose NMGR module experienced the error.
TEST Command Examples
The following examples illustrate the use of the TEST command.
Example 1. Defaulting All Parameters
NM> TEST<RETURN> ^1^2
error 1
NM>
Example 1 simply illustrates that a DSAP parameter is required.
5%42 Using Node Manager