Message IST489I or IST1272I received during session takeover

Problem statement

Message IST489I or IST1272I is received, indicating that VTAM® cannot define a resource.

Common symptoms

Message IST489I or IST1272I is received for a resource during takeover processing. The resource can be a dependent LU.

Probable cause

A scenario similar to the following condition can cause this problem:

Boundary function CP-CP sessions exist between SSCP1 and SSCP2. There is also an FID4 connection between SSCP2 and NCP1.
There is an SSCP-SSCP session between SSCP2 and SSCP3.
Dependent LU1, connected from NCP1, is owned by SSCP1.
An LU-LU session is between LU1 and LU2. LU1 is known to SSCP2 as an APPN LU through the APPN connection between SSCP1 and SSCP2 through NCP1.
The command VARY INACT TYPE=G was entered from SSCP1, which caused session takeover of the line from SSCP1 to SSCP2. SSCP2 owns LU2, the independent LU.

The failure, triggering message IST489I or message IST1272I, occurred because LU1 is known to the SSCP2 host as an independent APPN LU. SSCP2 cannot own the independent LU and the dependent LU at the same time.

User response

The independent LU is freed when the last session ends. After this occurs, you must activate the dependent LU before it can be enabled.