10.2.1 Single Connection and Multiple Links
As shown in the following figure, one CICS transaction links a remote program via DPL call, which maps to an Oracle Tuxedo service. The Tuxedo service is provided by one Tuxedo server and two GWSNAX/CRM pairs are configured to avoid any single point of failure.
Figure 10-3 Inbound Call (from CICS to Oracle Tuxedo)
The load balancing (round-robin) / failover can be accomplished via following two call paths:
MIRRRDPLC->DYPSAMP -> CRM12205 -> SNAX1 -> mirrsrv
MIRRRDPLC->DYPSAMP -> CRM12206 -> SNAX2 -> mirrsrvDynamic routing can be configured in CICS to dispatch the
request to two CRMs with load balance and failover automatically,
and the default dynamic routing program, DFHDYP,
should be customized accordingly.
DFHDYP is a CICS-supplied, user-replaceable program
for dynamic routing. For eligible DPL requests, it is invoked
before a linked program is executed, to obtain the
SYSID of the region where the link should be
routed.
The following table lists all the configurations required for making inbound calls of single connection and multiple links.
Table 10-3 Configurations for Single Connection and Multiple Links (Inbound)
| Machine | Component | Resource | Configuration |
|---|---|---|---|
TUXEDO |
UBBCONFIG |
*GROUPS
|
2 groups for 2 GWSNAX servers
|
*SERVERS |
2 GWADM / GWSNAX pair
|
||
| 1 application server (for inbound call) | |||
DMCONFIG |
*DM_LOCAL |
2 local domain: SNAX1, SNAX2
|
|
*DM_REMOTE |
2 remote domains: CICSA1, CICSA2
|
||
*DM_SNACRM |
2 CRM: CRM1, CRM2
|
||
*DM_SNALINKS |
2 LINK: CICSA1, CICSA2
|
||
*DM_EXPORT |
1 service in application server | ||
| MAINFRAME | VTAM list | Major node | 2 APPC LUs (for two CRMs) |
| CICSH | Resources | 2 CONNECTION/SESSION pairs for two LUs.
|
|
DFHDYP program: DYPSAMP
|
|||
TRANSACTION/PROGRAM for DPLC
|
|||
| SIT | DFHDYP initialization parameter: DTRPGM=DYPSAMP
|