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Choosing a Load Balancing Method

Siebel Systems supports two load balancing methods—Siebel load balancing and third-party HTTP load balancers. For a description of these two methods see About Load Balancing.

Siebel load balancing and third-party HTTP load balancers provide similar features. Table 4 compares key characteristics of Siebel load balancing with third-party HTTP load balancers. In the table, SISNAPI is the Siebel protocol used to communicate with Siebel Servers.

Table 4. Load Balancing Method Comparison
Feature Area
Siebel Load Balancing
Third-Party HTTP Load Balancer

Product form

Part of the Siebel Web Server Extension software.

Can be a dedicated device or part of an intelligent network switch. If it is software-based, it is usually installed on an available server.

Considered part of customer's networking infrastructure environment.


Part of the Siebel installation process.

Varies by vendor. Hardware-based load balancers must be physically installed on the network. May have network topology restrictions.


Supports SISNAPI protocol.

Must define server rules to support routing of SISNAPI connections.

Hardware-based load balancers are typically administered using a Web browser.

Software-based load balancers provide administration software.

Load balancing scheme

Round-robin only.

Response-time-based, resources-based, or round-robin.


No application-imposed hard limit.

Varies by vendor. Typical limiting factors are network traffic throughput and number of servers per load balancing pool.

Server health checks

Connection success or failure is monitored through SWSE stat page. No active checks.

Supports ICMP, TCP, and HTTP health-checks. HTTP health-checks are recommended.

Security and network access

Web server must directly connect to the application server.

Generally supports NAT, VIPs, VPorts. Also supports packet inspection and filtering.

Administration and configuration

Configured using text file. Administered through Siebel Server Administration.

Generally configured and administered through Web interface and command line tools.

Deployment limitations

All load-balanced servers should have same configuration and equal load capacity.

No limitations on load balancer except network topology requirements.

Load Balancing Guidelines

Third-party HTTP load balancers are a good choice when any of the following is true:

  • Hardware load balancers are already in use or are preferred.
  • They provide desired security features.
  • A more sophisticated load-balancing scheme is desired.
  • The site requires centralized monitoring and management of system hardware and network infrastructure.

Siebel load balancing distributes user login requests in a round robin fashion, which works best if all servers are configured equally and have similar capacities. Other considerations include the following:

  • Configure all load-balanced Siebel Servers with the same Maximum Tasks setting for an application.
  • Allocate all load-balanced Siebel Servers with an equal amount of server resources, such as CPU and memory configuration. For example, you will run Siebel Call Center on two Siebel Servers. One of them also will run Siebel Field Service. Siebel Call Center must compete for resources with Siebel Field Services on one of the servers. This is not recommended.
  • Once you have selected a load balancing method, it is important not to set the maximum number of tasks for an Application Object Manager (AOM) on a server or other load-balanced component higher than the server can reasonably handle. For information on planning and managing server task loads, see Performance Tuning Guide.
Deployment Planning Guide