Installing HostBridge is a simple step-by-step process. HostBridge is much like any CICS application: it has program files (load libraries), data files (configuration and script repositories) and CICS Resource Definitions (RDOs). HostBridge was designed and written  to operate in all IBM-supported CICS configurations (and a few that aren't).  If you have a single region, multiple regions operating independently, multiple regions in an MRO or hundreds of regions running in a CICSPLEX,  HostBridge can be installed to meet your requirements for availability, performance, security and maintenance.  

While an installation of HostBridge in a single region is relatively simple, the requirements of your environment and the flexibility of HostBridge mean that you have many choices in how and where HostBridge is installed.   Below are a couple of the more popular installation configurations we see at our customer sites.

Best Practice

You should have a completely separate HostBridge installation for each environment you support: development, test, QA and production.  By "completely separate", we mean a unique set of HostBridge libraries and data files. When new releases of HostBridge become available you will want to install it in development, only rolling it into the next environment after thorough testing.  The HostBridge load libraries can be shared without  concern across all regions in a single environment  (like development).  The HostBridge VSAM files can also be shared across regions as long as you follow standard CICS VSAM file sharing practices. See the HostBridge Wiki article "Sharing HostBridge Files" for more information.

Region Installation Options

One of the first decisions you will have to make is into which regions you want to install HostBridge. These options are summarized as follows:

Option 1: Install HostBridge in every region

HostBridge can be installed in every region that contains applications, transactions or data you want to access via HostBridge.

Requirements

  • Two TCP/IP ports have to be assigned to each region
  • CICS Resource Definitions have to be installed in each region
  • HostBridge load library has to be added to the CICS RPL of each region

Advantages

  • No MRO requirements, definitions or connections
  • Installation, while repetitive, is simple

Disadvantages

  • Sharing the HostBridge script repositories across multiple regions can be limiting unless a File Owning Region (FOR) is used
  • Maintenance of the HostBridge installation can be more complex as multiple copies of Resource Definitions must be maintained (unless all regions share a common CSD file).
  • The middle tier applications must be aware of what region hosting the CICS transactions they are using, and what ports are assigned to those regions. Different ports have to be used to invoke applications that live in different regions. It is conceivable that multiple invocations to different ports would be required to complete a single web process.
  • Every region HostBridge is installed into is a web service point of entry

Option 2: Install HostBridge in its own region

HostBridge can be installed into a single region that is connected to other Application Owning Regions (AOR) via MRO. Conceptually, this is analogous to having Terminal Owning Regions(TORs) and AORs. Some customers choose to install HostBridge in the TORs because these regions already have the necessary MRO resource definitions. Other customers "clone" a TOR to create a "Web Owning Region" (WOR). It functions similarly to a TOR except that they segregate terminal and Web traffic.  Based on our experience with a variety of customers, HostBridge views this as the preferable option.

Requirements

  • Two TCP/IP ports have to be assigned to the HostBridge region
  • HostBridge CICS Resource Definitions are installed in the HostBridge region
  • HostBridge load libraries are added to the CICS RPL in the HostBridge region
  • MRO connections have to be defined between the HostBridge region and regions that contain the application, transactions or data you want to access via HostBridge
  • Transactions/programs have to be defined in the HostBridge region to point to the remote regions where the transaction/programs actually reside
  • For optimal performance, load libraries that contain BMS maps should be added to the HostBridge region's RPL.  This is strongly recommended.

Advantages

  • After initial installation, maintenance of the HostBridge components is simpler as they are all in a single region
  • Middle-tier applications only have to use one set of ports to access all CICS applications, transactions and data
  • The HostBridge region can be tuned specifically for web services
  • Logging, debugging, auditing, security are simpler as there is a single point of entry for web services into the environment

Disadvantages

  • Initial installation is more complex than the installation of HostBridge in a single region
  • MRO connections are required between the HostBridge region and the application regions
  • Remote transaction and program definitions are required in the HostBridge region
  • Load libraries containing BMS maps should be added to the HostBridge region RPL

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