Overview

Universal Connector supports two modes of client fault tolerance:

1. Secure Client Fault Tolerance (Secure CFT)
2. Pre-XBP 2.0 Client Fault Tolerance (CFT)

The mode of client fault tolerance to be used by Universal Connector is determined by the value of the SECURE_CFT option.

Valid values for this option are yes and no:

• yes will cause Universal Connector to use the Secure CFT mode.
• no will cause Universal Connector to use the original Pre-XBP 2.0 CFT mode.

The default value is yes.

Both modes of CFT follow the same basic process flow. When Universal Connector is requested to restart a particular command ID process chain, it queries the SAP system for all jobs with the specified job name (the chain ID is used for the job name). The list of jobs returned by the SAP system is scanned for a job that contains an appropriate Command ID Job Step. If found, Universal Connector will re-connect to the SAP process chain instance associated with the job and satisfy the command line requirements.

Universal Connector is capable of restarting a command ID as long as the associated command ID job remains in the SAP system.

Secure Client Fault Tolerance (Secure CFT) Mode

This mode is an enhancement of the original implementation. The secure CFT mode requires XBP 2.0 to be installed on the SAP side of the Universal Connector connection. In this mode, an ABAP program job step is used for the log ID step and the command ID step.

Using an ABAP program job step as the log ID and Command ID steps eliminates the security and ease of use drawbacks mentioned above for external program steps.

• Security
  The execution of ABAP programs and the resources required by them are secured by SAP authorization checks.
• Ease of Use
  ABAP program job steps do not require a target host. They run on whichever application server the job runs on. Therefore, there are no target specific parameters required for secure CFT mode.

Pre-XBP 2.0 Client Fault Tolerance (CFT) Mode

This mode is the original implementation of client fault tolerance used prior to the release of XBP 2.0. Due to limitations in the XBP 1.0 interface, Universal Connector client fault tolerance on pre-XBP 2.0 SAP systems uses an external program step as the log ID and command ID steps.

Using external program steps as the log ID and command ID steps has the following security and ease of use drawbacks:

• Security drawback
  The dummy job used for client fault tolerance with process chains is never actually run by the Universal Connector so, there is no security drawback.
• Ease of use drawback
  Using an external program step requires a target host be specified for the external program to run on. This requires information about the SAP landscape that may not be readily available. Also, this presents the possibility of the Universal Connector job's parameters becoming out of sync with the SAP landscape.