parameter value on one system should never have a greater value than the LANMAXOUT parameter value on the other system. The parameter values of the sending system should match the values on the receiving system.

vSetting appropriate values for the LANMAXOUT parameter along with the LAN acknowledgment frequency (LANACKFRQ) parameter for both the sending stations and receiving stations is essential for optimal performance. Other values may decrease throughput by 50% or even more if conditions trigger time-outs.

vLANWDWSTP for advanced program-to-program communications (APPC) on the controller description (CTLD): If there are network congestion or overruns to certain target system adapters, then increasing the value from the default of *NONE to 2 or more may improve performance.

In general, setting the LANMAXOUT parameter value to *CALC or 2 offers the best performance for interactive environments and adequate performance for larger transfer environments.

vFor large transfer environments, changing the LANMAXOUT value may significantly increase performance. As starting points, use the following guidelines:

–When you are communicating with a recent model personal computer, increase the LANMAXOUT parameter, but keep the LANACKFRQ parameter set to *CALC. For older models of personal computers, use *CALC for both values to limit buffer overruns.

–If LANACKFRQ and LANMAXOUT parameter values are changed without noticeable performance improvements, change the values back to *CALC.

For more information on AS/400 communications, see the Communications Configuration book.

LAN line speed considerations for IOPs

When configuring an AS/400 system with communications lines and local area networks (LANs), you should not overload an input/output processor (IOP) to prevent possible system performance bottlenecks.

The following information can help you to understand the line speed considerations for IOPs.

vThe integrated PC server performance is similar to the 2619 and the 2617 IOPs for host LAN functions. For send and receive scenarios, performance is equivalent. For large transfers, the 6506 IOP is slightly faster than the 2619 TRLAN IOP, but slightly slower than the 2617 Ethernet IOP. These differences are not significant enough to choose one over the other.

vThe 100 Mbps Ethernet support provides the best LAN performance. The IOP can be optimally configured to have an aggregate transfer rate of 27 Mbps. Multiple concurrent large transfers may be required to drive at that rate.

vWhen analyzing communications performance that includes the 2619 TRLAN IOP, you should be aware that resources other than the IOP use can become the bottleneck.

vYou should have the highest capacity IOP available for file serving. You should have the highest capacity IOP available for environments that use many communications input and output operations for each transaction. The highest capacity IOP also minimizes the overall response time.

See the following references for more detail:

vFor more information about AS/400 communications, see the Communications Configuration book.

vFor more information on IOP performance, see the Performance Tools for AS/400 book.

Improving data path performance

To assess the performance of your data path, you may want to review the following topics:

vConsiderations for subsystem configuration for error recovery performance

vCommunications performance considerations for interactive jobs

vConsider communications performance for batch jobs

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IBM AS/400 manual LAN line speed considerations for IOPs, Improving data path performance
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AS/400 specifications

The IBM AS/400, now known as the IBM iSeries, is a midrange computer system that has been a cornerstone of enterprise computing since its introduction in 1988. Designed to provide a robust platform for business applications, the AS/400 is celebrated for its reliability, scalability, and integrated database capabilities.

One of the key features of the AS/400 is its Integrated Operating Environment, which blends hardware and software resources seamlessly. This integration allows businesses to execute diverse workloads, ranging from traditional applications to modern web-based services, all on a single platform. The operating system, OS/400 (now IBM i), offers a rich set of APIs and tools for developers, simplifying application development and management.

Another standout characteristic of the AS/400 is its built-in database, DB2 for i. This powerful relational database management system allows for efficient data handling and provides advanced features such as support for SQL, XML, and JSON, making it easier for businesses to manage their data and integrate it with other systems. The database's tight integration with the operating system enables high performance and security.

In terms of scalability, the AS/400 can accommodate small businesses as well as large enterprises, with the ability to support hundreds of users simultaneously. Its architecture allows for easy upgrades in hardware, meaning that organizations can scale their systems without replacing the entire infrastructure.

Security is another critical attribute of the AS/400. With a sophisticated security model, it offers built-in user authentication, access control, encryption, and auditing capabilities to protect data and applications from unauthorized access.

The AS/400 also supports multiple programming languages, including RPG, COBOL, Java, and PHP, giving organizations the flexibility to choose the development tools that best fit their needs. This diversity helps maintain legacy applications while also developing new ones that leverage modern technologies.

Moreover, the platform supports both traditional green-screen interfaces and modern graphical user interfaces, allowing organizations to transition smoothly into contemporary user experience paradigms.

Overall, the IBM AS/400 stands out as a resilient, flexible, and secure computing platform that enables organizations to effectively manage their business operations, streamline processes, and adapt to changing market demands. Its unique combination of integrated features and capabilities ensures that it remains relevant in today's fast-paced technology landscape.
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