Analysis

Table 1 lists some of the common SNALINK LU6.2 address space network establishment problems.

Table 1. SNALINK LU6.2 address space network establishment problems
If this is displayed. . .	Then this might have occurred . . .	Resolution
The SNALINK LU6.2 address space issued error message: `Unable to allocate send conversation`.	This problem can be due to one of the following situations: The local VTAM® application LU might not be enabled for LU type 6.2 conversations. The name of this LU is specified on the VTAM statement in the SNALINK LU6.2 configuration data set. The remote VTAM application LU names might not identify an LU that is reachable or that can establish an LU type 6.2 conversation over the SNA network. The remote VTAM application LU name is specified in the DEST statement of the SNALINK LU6.2 configuration data set. For dependent LUs, both the SEND and RECV LU names must be able to establish LU type 6.2 conversations.	The APPC option in the VTAM application LU definition must be set to YES to enable LU type 6.2 conversations. The first step is to check to see whether the remote SNALINK LU6.2 device is active. If the remote SNALINK LU6.2 is using VTAM to access the SNA network, see Useful VTAM operations to check the active status of the remote LU. If the remote SNALINK LU6.2 device is active, use the VTAM error messages to determine why the LU type 6.2 conversation cannot be established with the destination LU. The VTAM error messages are written to the MVS™ system console immediately before the `Unable to allocate send conversation` message. VTAM sense code documentation can be found in z/OS Communications Server: SNA Messages and z/OS Communications Server: IP and SNA Codes. These messages might indicate a network configuration or hardware error.
VTAM error message output to the MVS system console: `REQUIRED LOGMODE NAME UNDEFINED`.	To allocate LU type 6.2 conversations over an SNA network, both sides must specify matching log modes. The VTAM log modes are defined in log mode tables. The log mode configured for use with this connection cannot be found in the log mode table specified on the VTAM application LU definition.	The log mode entry name specified as the LOGMODE parameter on the LINK statement in the SNALINK LU6.2 configuration file must exist in the log mode table specified on the MODETAB statement in the VTAM application LU definition.

The following list contains some of the common SNALINK LU6.2 address space network establishment problems. Each error symptom is listed with possible causes and resolutions.