Configuring SISNAPI Connection Pooling for Siebel Application Object Managers

This topic provides information about how to manage SISNAPI (Siebel Internet Session application programming interface) connections for your Siebel Server.

SISNAPI, a messaging format that runs on top of the TCP/IP protocol, is used for network communication between Siebel Application Object Manager and Siebel Application Interface. SISNAPI connections use encryption and authentication based on Transport Layer Security (TLS).

Each multithreaded process for a Siebel Application Object Manager component uses a pool of SISNAPI connections managed by the Siebel Application Interface. The process multiplexes (shares) many client sessions over each connection.

Each client session request opens a new connection and adds it to the pool, until the number of connections defined by the value of the parameter SessPerSisnConn have been created. Subsequent requests are then multiplexed over the existing pooled connections. SISNAPI connections persist until one of the following events occur:

• The Siebel Application Interface process terminates.

• The Siebel Application Object Manager component terminates.

• The value of the parameter SISNAPI Connection Maximum Idle Time (alias ConnIdleTime) is reached. For more information on this parameter, see Siebel System Administration Guide.

• Your firewall times out the connection.

Multiplexing traffic over a set of SISNAPI connections helps to reduce the number of open network connections.

The SISNAPI connection pool size per multithreaded process for a Siebel Application Object Manager is determined by the combined settings of MaxTasks, MaxMTServers, and SessPerSisnConn. In general, the maximum number of SISNAPI connections created would approximately equal MaxTasks divided by MaxMTServers, then divided by SessPerSisnConn (resolved to an integer).

SessPerSisnConn determines how many sessions can be multiplexed over a single SISNAPI connection. By default, SessPerSisnConn is set to 20 for Siebel Application Object Manager components. This figure is suitable for most deployments and generally does not need to be changed. You might set this differently, depending on how you have calculated think time. For example, for Siebel EAI, this value must be set to a much lower value, such as in the range of 3 to 5. For more information, see "Performance Factors for Siebel Application Object Manager Deployments". For more information about configuring MaxTasks and MaxMTServers, see "Tuning Siebel Application Object Manager Components for CPU and Memory Utilization".

Caution: If you set SessPerSisnConn to a value of 1, then you must set the parameter ConnIdleTime to a value other than -1 (its default value). Otherwise, this combination of settings might cause the Siebel Application Interface to stop running.

The number of actual SISNAPI connections per multithreaded process for the Siebel Application Object Manager is determined by the following formula:

(MaxTasks divided by MaxMTServers) divided by SessPerSisnConn = SISNAPI_conn_per_process

In this formula, SISNAPI_conn_per_process represents the number of SISNAPI connections per multithreaded process.

Assume, for example, the following parameter values:

MaxTasks = 600
MaxMTServers = 5
SessPerSisnConn = 20

In this case, the formula would be:

(600 divided by 5) divided by 20 = 120 divided by 20 = 6

Or, if MaxTasks = 540 and SessPerSisnConn is set to 18, then the formula would be:

(540 divided by 5) divided by 18 = 108 divided by 18 = 6

In each case, six SISNAPI connections will be created and pooled for each Siebel Application Object Manager multithreaded process, from each Siebel Application Interface. Each Siebel Application Interface can potentially have its own set of six connections, so the maximum total number of connections into a Siebel Application Object Manager process is six times the number of Siebel Application Interface instances. In the first example above, 20 sessions would be multiplexed over each connection. In the second example, 18 would be multiplexed over each connection.

Note: In general, it is recommended that the figures used for the above formula be tailored to produce an end result that is an integer. To achieve this, you might need to modify how you define MaxTasks, MaxMTServers, and SessPerSisnConn.

Some Object Manager components are not Siebel Application Object Manager components. Configuration issues for such components differ from those applicable to Siebel Application Object Manager components. For information about the EAI Object Manager, see Chapter 9, "Tuning Siebel EAI for Performance."