If you have the Silicon Graphics optional LU 6.2 product installed, you can use IRIS SNAView to manage SNA LU 6.2 sessions and to control the number of sessions that are active in the LU 6.2 network. Press the Session Operator button in the Operation Panel of the SNAView main window to display the LU 6.2 Session Operator dialog box.
This dialog box, which is used for all of the operations, has two subareas: Session Operator and Session Parameters/Actions. First select the radio button for the desired operation in the Session Operator subarea. Then fill in the requested information (indicated by highlighted text) in the Session Parameters/Actions subarea below.
In addition to the usual Apply, Cancel, and Help buttons, the LU 6.2 Session Operator dialog box has the LU Status and Session Status push buttons, which are described in this chapter.
The Session Operator radio buttons enable you to initialize the Service Manager mode; initialize, change, and reset session limits; and activate and deactivate sessions. This section describes these operations.
The Initialize Service Manager Mode radio button initializes the Service Manager Mode—the privileged logical connection between your LU and your partner's LU in a peer connection.
Initialize the Service Manager Mode by selecting the radio button and entering the names of the local and remote LUs involved in this connection in the text boxes in the Session Parameters/Actions subarea. This action issues the initsl control operator verb for the SNASVCMG (SNA Service Manager) Mode.
 | Note: There is no Service Manager Mode in host-mediated connections. |
A successful action produces the message, Mode Initialization Complete. If unsuccessful, a major and minor return code will be displayed in the message line area of the Information Panel in the IRIS SNAView main window. Specific return code information is given in Appendix B, “Major and Minor Return Codes.”
LUs use this privileged mode to negotiate the limits on the other modes between the two LUs. When session limits are initialized, changed, or reset on the user modes, the two LUs involved must agree on the new limits. This agreement is reached by having the source of the change allocate a conversation with a special agent program at the target. This agent program is called the Change Number of Sessions model, or CNOS.
The conversation between the source program issuing your command and the target CNOS program occurs over the Service Manager Mode. Consequently, the Service Manager Mode must be initialized by both LUs before any other mode can be initialized. The two LUs do not need to negotiate the session limits for the Service Manager Mode since the limits are predefined for all LUs by the LU 6.2 architecture.
Three radio buttons are associated with session limits: Initialize Session Limits, Change Session Limits, and Reset Session Limits.
The Initialize Session Limits radio button establishes initial session limits and contention-winner minimums between the local LU and its partner for the specified mode. It activates any auto-initiated sessions specified in the Defining Other Properties (Mode) dialog box (see “Defining Other Properties for Mode” in Chapter 3) and is valid only when session limits are 0. If the mode is for a peer connection, the Service Manager Mode for both LUs must already be initialized.
The Initialize Session Limits option issues the initsl control operator verb.
After selecting the Initialize Session Limits radio box, enter the following information in the Session Parameters/Actions text boxes:
Local LU name
Remote LU name
Mode name
Session limits (maximum sessions, minimum first speaker, and minimum bidder session)
Specifying the minimum first-speaker and bidder limits guarantees that each LU is allotted a minimum number of sessions in which to initiate a conversation (providing no conversation is active) without having to bid for the right to begin with a partner. The limits specified cannot exceed the limits configured for the mode block. The actual number of sessions started can be less than this number, however, if there are insufficient system resources to support the number of sessions requested.
Selecting the Change Session Limits radio button changes session limits and polarities specified in Initialize Session Limits for parallel-session connections between the local and remote LUs under the specified mode name.
The Change Session Limits option issues the chgsl control operator verb.
Use this option to tailor the performance of LU 6.2, given varying levels of system activity. For example, when using LU 6.2 in an inventory distribution system, reduce session limits (which reduces the possible number of active programs that can use LU 6.2) during month-end accounting activities and increase session limits during the peak order-taking hours.
Enter the following information in the text entry boxes in the Session Parameters/Actions subarea of the LU 6.2 Session Operator dialog box (see Section , “Setting Session Parameters and Actions,” for a description of these parameters):
Local LU name
Remote LU name
Mode name
Session limits (maximum sessions, minimum first speakers, minimum bidder session)
Responsibility: Source/Target
The Responsibility: Source/Target radio buttons refer to the side (either source or target) responsible for bringing down sessions in response to lowered session limits.
Selecting the Reset Session Limits radio button resets the session limits to 0 for a given mode or all modes between the local and the remote LU. As conversation activity ends, the sessions are deactivated.
The Reset Session Limits option issues the rstsl control operator verb.
Enter the following information in the text entry boxes or select the appropriate radio buttons in the Session Parameters/Actions subarea of the LU 6.2 Session Operator dialog box (see Section 5.2 for a description of these parameters):
Local LU name
Remote LU name
All modes (enter mode name in the Session Parameters/Action text box only if you do not select the radio button)
All modes resets all modes between the local and remote LUs. If All Modes is not selected, the specified mode is reset.
Drain Source
Establishes whether or not the source can drain its conversation requests. If this radio button is selected, all pending conversation requests and new conversation requests can be honored if conversations are active.
Drain Target
Establishes whether or not the target can drain its conversation requests. If this radio button is selected, all pending conversation requests and new conversation requests can be honored if conversations are active.
Force Reset
Specifies whether or not session limits can be lowered if the partner is unable to be notified of this change. For example, if the communications line has dropped, the CNOS negotiation will fail. Selecting the Force Reset radio button resets the limits.
Responsibility: Source/Target
This radio button determines whether or not the target initiates the session take-downs.
Select the Activate Session radio button to explicitly activate a session with the remote LU, using the properties defined by the specified mode. (This action issues the actses control operator verb). If the maximum number of minimum first-speaker sessions has not been reached, the session is activated as a first-speaker session. Otherwise, the session is activated as a bidder session.
Enter the following information in the text entry boxes or select the appropriate radio buttons in the Session Parameters/Actions subarea of the LU 6.2 Session Operator dialog box (see Section 5.2 for a description of these parameters):
Local LU name
Remote LU name
Mode name
| Note: Explicitly activating a session is one of three ways to activate a session. Sessions are usually activated at session-limit initialization time if auto-initiated sessions are configured. Sessions can also be activated in response to a program's request for a conversation if no sessions are available and session limits have not been reached. |
Selecting the Deactivate Session radio button deactivates a specific session immediately or when the current conversation allocated to the session is deallocated.
The Deactivate Session option issues the dctses control operator verb.
With auto-initiated sessions, the LU can automatically activate a session to keep the number of active sessions at the auto-initiated limit. That is, it activates them as quickly as you deactivate them. To terminate session activity in this case, select the Reset Session Limits radio button.
Enter the following information in the text entry boxes or select the appropriate radio button in the Session Parameters/Actions subarea of the
LU 6.2 Session Operator dialog box (see Section 5.2 for a description of these parameters):
Local LU name
Remote LU name
Mode name
Session ID
To determine the Session ID (Session Control Block ID), press the Session Status button, which displays the Session Status dialog box shown in Figure 5-2. The Session ID is shown in the ID text box.
Immediate Deallocation
When the Immediate Deallocation radio box is selected, the session is deactivated immediately, even if a conversation is using it. When Immediate Deallocation is not selected, the session is deactivated after any current conversation is completed.
Session operation is controlled by the following text box parameters and radio buttons. Enter the required information and select radio buttons as described in Section :
LU Name
Enter the local LU name for the connection.
RLU Name
Enter the remote LU name for a connection.
Mode Name
Enter the mode name of the mode definition given in the configuration file for a connection.
Maximum Sessions
Enter the maximum number of simultaneously active sessions for a connection (1 to 254; the default is 6).
Minimum First Speaker
Enter the minimum number of sessions in which the local LU is the contention winner (1 to 254; the default is 3). The sum of this value and the value for the Minimum Bidders Sessions should not be greater than the value for Maximum Sessions.
Minimum Bidder Sessions
Enter the minimum number of sessions in which the remote LU is the contention winner (1 to 254; the default is 3). The sum of this value and the value for the Minimum First Speaker should not be greater than the value for Maximum Sessions.
Enter the identification of the session to be deactivated. The value is obtained from the ID text box in the Session Status window. See Section , “Deactivate Session.”
All Modes
If selected, resets all modes between the local and remote LUs. If not selected, resets the mode you entered in the Mode Name text book.
Drain Source
Establishes whether the source can drain its conversation requests. If selected, all pending conversation requests and new conversation requests can be honored if conversations are active.
Drain Target
Establishes whether or not the target can drain its conversation requests. If selected, all pending conversation requests and new conversation requests can be honored if conversations are active.
Forced Reset
Specifies whether or not the session's limits can be lowered if the partner is unable to be notified of this change. For example, if the communications line has dropped, the CNOS negotiation will fail. Selecting this radio button resets the limits.
Immediate Deallocation
Select this to deactivate a session immediately, even if it is being used by a conversation.
Responsibility: Source/Target
Select the radio button that indicates whether the source or target initiates the session take-down.
To view the status of the LUs for the current configuration, press the LU Status button in the LU 6.2 Session Operation window, which displays the LU Status dialog box shown in Figure 5-1.
Each line of the display show the status of a triplet consisting of the local LU, remote LU, and mode. The text window below the line(s) shows the names of these items. The Active check box is filled if the local LU is active.
The Maximum Session text box shows the maximum session limit configured for the triplet. The Current Maximum Session text box shows the maximum session limit value set through Initialize Session Limits (see Section ). The Active FSPK text box shows the number of active first speaker sessions (respective to the local LU). The Active Bidder text box shows the number of active bidder sessions (respective to the local LU).
To view the status of sessions related to the triplet of local LU, remote LU, and mode, press Session Status in the LU 6.2 Session Operator dialog box, which displays the Session Status dialog box shown in Figure 5-2.
Each line of the display shows the status of a session between the local and remote LU, as well as the mode status. The text boxes under LU, Remote LU, and Mode show the names of the local, remote LU, and mode triplet, respectively. The ID text box shows the session ID when the session is activated, and is blank when the session is not activated. This ID identifies the session to deactivate in the Deactivate Session operation described in Section .
The FSPK box indicates whether the session is a first speaker session or a bidder session respective to the Local LU. If the CONVID (Conversation ID) text box is blank, the session is not used; otherwise, the identified conversation is being allocated to the session. The value in the TPID and PPID text boxes shows the internal ID and UNIX® process ID related to the transaction process instance that triggers the conversion.