TCP/IP in a Sysplex

An IBM Redbooks publication


The sysplex environment provides a unique setting for the creation of high performing application servers. Quite simply, the main goals of a sysplex are high availability and load balancing. That is, the sysplex provides the ability to maintain a service as highly available and the ability to add resources so that service performance can scale with growing number of client requests.

In this IBM Redbooks publication, we include the discussion of three sysplex-specific solutions that help to meet these demands, Sysplex Distributor, Domain Name Service/Workload Manager, and Network Dispatcher. All of these solutions make use of, to some extent, the MVS Workload Manager (WLM). Because of this, we describe the benefits of WLM-aware system solutions and include mechanisms by which we can work with WLM. Additionally, because the sysplex notion of high availability is so closely tied together with the Virtual IP Addressing (VIPA) concept, we discuss the advantages of VIPA and the necessary steps that need to take place when using VIPA. This includes a detailed routing discussion as we deal with VIPAs in the sysplex.

The main focus of this book is Sysplex Distributor, a new function available on sysplex systems as of IBM Communications Server for OS/390 V2R10 IP. Sysplex Distributor is the state of the art technology of achieving efficient load balancing and high availability within the sysplex.
In summary, this book will help you design your OS/390-based IP network to gain the maximum benefit from the features available with the sysplex to achieve the high availability and load balancing demands placed on your OS/390 servers.

Table of contents

Chapter 1. Introduction to TCP/IP in a sysplex
Chapter 2. DNS/WLM (connection optimization)
Chapter 3. Network Dispatcher
Chapter 4. Dynamic VIPA (for application instance)
Chapter 5. Automatic VIPA takeover and takeback
Chapter 6. Routing in a sysplex environment
Chapter 7. Sysplex Distributor
Appendix A. Sample applications and programs
Appendix B. Sample C program source code
Appendix C. REXX EXECs to gather connection statistics
Appendix D. Profiles, data files and parameter files
Appendix E. Dump of T28ATCP name server - single-path network

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Publish Date
02 April 2001

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