Interregion Communication

This section describes the additional costs of communication between two CICS® regions using the following communication methods:

MRO XM
This is CICS to CICS communication where both regions are in the same MVS™ image. CICS uses MVS cross memory (XM) services for this environment.
MRO XCF (via CTC)
This is CICS to CICS communication where both regions are on separate MVS images. In this environment the transport class is defined to use a XCF path that exploits a channel to channel (CTC) device for message traffic between the two MVS images. This is only supported within a sysplex.
MRO XCF (via CF)
This is CICS to CICS communication where both regions are on separate MVS images. In this environment the transport class is defined to use an XCF path that exploits a CF structure for message traffic between the two MVS images. This is supported only within a sysplex.
ISC LU6.2
This is CICS to CICS communication where both regions are on separate MVS images. In this environment VTAM® LU6.2 uses a CTC for communication between the two MVS images.

Transaction routing

MRO XM MRO XCF (via CTC) MRO XCF (via CF) ISC LU6.2
37.0 43.0 66.0 110.0

Function shipping (MROLRM=YES)

MRO XM MRO XCF (via CTC) MRO XCF (via CF)
Initiate/terminate environment 13.2 13.2 13.2
Each function shipping request 9.0 23.4 48.4
Syncpoint flow 9.0 23.4 48.4
Notes:

The above costs relate to CICS systems with long running mirrors.

ISC LU6.2 does not support MROLRM=YES.

Included in the initiate/terminate environment is the cost of:

  • Session allocation, initiation of the mirror transaction, termination of the mirror transaction, and session de-allocation.

For example, if you were migrating from a local file access to MRO XM and requesting 6 function ships per transaction, the additional cost could be calculated as follows:

13.2(Initiate/Terminate)+6(requests)*9.0(Request Cost)+ 9.0(Syncpoint) = 76.0

Function shipping (MROLRM=NO)

Without long running mirrors each function ship read request incurs the cost of session allocation and mirror initialization and termination. However, the first change to a protected resource (for example, a READ UPDATE or a WRITE) causes the session and mirror to be held until a syncpoint.

MRO XM MRO XCF (via CTC) MRO XCF (via CF) ISC LU6.2
21.4 35.0 59.9 115.0
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