Enhanced description of InfoSphere Guardium S-TAP for DB2 on z/OS network parameters.

Resolving The Problem

InfoSphere Guardium S-TAP for DB2 provides network parameters that can improve the stability of your connection to the Guardium appliance. Set appropriate values for the following parameters to decrease the potential for temporary network disruptions.

The APPLIANCE_NETWORK_REQUEST_TIMEOUT parameter corresponds to the TCP/IP SO_SNDTIMEO option for the socket API that is used in the connection. This parameter sets the timeout value to the amount of time for which a TCPIP BPX4WRT API function (such as send or write) is blocked, due to flow-control that prevents data from being sent. This parameter is used for all connections.

Each interface (IFI, Policy, and ASC) uses a different send buffer. The timeout value depends on the buffer usage, which is determined by the data rate for each interface. During non-blocking calls, which are invoked during the data-sending phase of the connection, the timeout does not begin until the TCP/IP internal buffers are filled.

APPLIANCE_NETWORK_REQUEST_TIMEOUT
Default: 0
Range: 0 or 500 - 12000
Description: The value in milliseconds of the period of time to wait for network communication requests to be sent or received. A value of 0 indicates no timeout period.
Syntax:
APPLIANCE_NETWORK_REQUEST_TIMEOUT(timeout)
Example:
APPLIANCE_NETWORK_REQUEST_TIMEOUT(0)

The APPLIANCE_PING_RATE parameter controls the rate at which ping messages are sent from the InfoSphere Guardium S-TAP for DB2 on z/OS Collector Agent to the Guardium appliance. The purpose of the ping is to send data in situations where no audit data is being collected over a period of time. This prevents the Guardium appliance from disconnecting from the InfoSphere Guardium S-TAP for DB2 on z/OS Collector Agent due to an idle connection. The ping refreshes the status indicator for the connection to the Guardium appliance.

Note: Ping messages are InfoSphere Guardium S-TAP internal data messages. They are not equivalent to the ICMP messages that are sent by the PING command.
InfoSphere Guardium S-TAP ping messages are sent by using the TCP/IP API BPX4WRT. If a network outage is caused by a cable disconnection, the BPX4WRT call might return successfully, and the ping message will be buffered in the TCP/IP internal buffers. Pings will continue to be sent until the TCP/IP internal buffers are filled and the disconnection is detected. The same situation occurs with the sending of audit data messages.

APPLIANCE_PING_RATE
Required: No
Default: 5
Description: Specifies the time interval between accesses to the Guardium system to prevent timeouts (disconnects) during idle periods. The value is in number of seconds.
Syntax:
APPLIANCE_PING_RATE(ping_interval)
Example:
APPLIANCE_PING_RATE(5)

Note: InfoSphere Guardium S-TAP for DB2 on z/OS requires TCP/IP connectivity to communicate with the Guardium appliance. The use of network parameters cannot maintain connectivity with the Guardium appliance in the case of a hardware failure, such as a cable disconnection or power outage. For more information about TCP/IP connections, refer to the IBM TCP/IP Tutorial and Technical Overview: http://www.redbooks.ibm.com/redbooks/pdfs/gg243376.pdf.