Notes on IMS

 

The LU6.2 User Callback has been tested with the IMS LU6.1 Adapter for LU6.2 applications. The IMS LU6.1 Adapter is a VTAM program that provides bidirectional translation between the LU6.1 protocol used by the IMS Inter-System Communications (ISC) facility and the LU6.2 procotol used by APPC. A number of restrictions apply to the use of APPC verbs with the IMS LU6.1 Adapter. These restrictions are described in the IMS LU6.1 Adapter software documentation.

Users who want to communicate with IMS using the LU6.2 User Callback should take note of the following additional restrictions:

• Synchronization level

  The IMS LU6.1 Adapter does not provide direct support for SYNC_LEVEL=CONFIRM. When operating at SYNC_LEVEL=CONFIRM, confirmation from the IMS LU6.1 Adapter indicates that the transaction has been accepted by the IMS queue manager, not that the transaction has been processed by the target queue.

• Error handling

  The IMS LU6.1 Adapter does not support normal methods of signaling errors through APPC. Programmers developing applications that require this capability must design their applications accordingly.

• Transaction program names

  The IMS LU6.1 Adapter uses a constant TPN (IMSASYNC) when attaching remote LU6.2 applications. This means that the TPN cannot be used to distinguish inbound (from the IBM system) conversations from each other. Programmers developing applications that require this capability must design their applications accordingly.

• Session establishment

  The IMS LU6.1 Adapter supports establishment of an SNA session on behalf of IMS, but only if the IMS /OPNDST command is issued to request the session. Applications can eliminate this requirement by having the LU6.2 User Callback request the session. To do this, set the LU62_DEFINE_INIT_TYPE field in the LU62_DEFINE_LU message for the LU that is to accept incoming conversation to 0 (zero). The session is then established by sending an LU62_ACTIVATE message for the LU. Following activation of the session, the IMS LU6.1 Adapter can use the session.

  Note: Prior to activating the session, at least one valid local TPN must be established by sending an LU62_DEFINE_TP message to the User Callback. Failure to establish valid TPNs prior to session activation results in allocation failures in the IMS LU6.1 Adapter.