User’s Guide

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TMA/SNA High Availability

TMA SNA supports full high availability connection between Oracle Tuxedo and CICS, with no single point failure. Both bidirectional load balancing and bidirectional failover are supported.

This chapter discusses the following topics:

Outbound Call (from Oracle Tuxedo to CICS)

Figure 9-1 Outbound Call (from Oracle Tuxedo to CICS)

Outbound Call (from Oracle Tuxedo to CICS)

Overview

One Tuxedo client calls a remote service, which maps to a CICS DPL program. The DPL program runs in two CICS regions – CICSA and CICSB. Meanwhile, two GWSNAX/CRM pairs are configured to avoid any single point of failure. Each CRM connects to both CICS regions.

In this sample, there are four types of call paths:

Client -> SNAX11 -> CRM1 -> CICSA

Client -> SNAX11 -> CRM1 -> CICSB

Client -> SNAX12 -> CRM2 -> CICSA

Client -> SNAX12 -> CRM2 -> CICSB

Load balancing from Client to GWSNAX follows Oracle Tuxedo load balancing behavior. Load balancing from CRM to CICS is round robin.

Outbound Configuration

Table 9-1 Outbound Configuration
Machine
Component
Resource
Configuration
TUXEDO
UBBCONFIG
*GROUPS
2 groups for 2 GWSNAX servers
   
*SERVERS
2 GWADM/GWSNAX pairs
 
DMCONFIG
*DM_LOCAL
2 local domains: SNAX11, SNAX12
   
*DM_REMOTE
4 remote domains: CICSA1, CICSB1, CICSA2, CICSB2
   
*DM_SNACRM
2 CRMs: CRM1, CRM2
   
*DM_SNALINKS
4 LINKs: CICSA1, CICSB2, CICSA2, CICSB2
   
*DM_IMPORT
4 remote homonymous services : DPLS
Mainframe
VTAM list
Major node
2 APPC LUs (for two CRMs)
 
CICSA
Resource
2 CONNECTION/SESSION pairs (for two CRMs)
     
1 PROGRAM for DPLS
 
CICSB
Resource
2 CONNECTION/SESSION pairs (for two CRMs)

Inbound Call (from CICS to Oracle Tuxedo)

Figure 9-2 Inbound Call (from CICS to Oracle Tuxedo)

Inbound Call (from CICS to Oracle Tuxedo)

Overview

One CICS transaction links a remote program via DPL call, which maps to an OracleTuxedo service. The Tuxedo service is provided by two Tuxedo servers reside separately on two Tuxedo domains – TUX1 and TUX2. Meanwhile, two GWSNAX/CRM pairs are configured to avoid any single point of failure.

The load balancing (round-robin) / failover can be accomplished via following 2 call paths:

DPLC -> CRM1 -> SNAX11 -> Server

DPLC -> CRM2 -> SNAX21 -> Server

Dynamic 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; (you can use the default program as a model and write your own program). 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. For more information, see IBM (CICS Intercommunication Guide).

Inbound Configuration

Table 9-2 Inbound Configuration
Machine
Component
Resource
Configuration
TUX1
UBBCONFIG
*GROUPS
1 group for 1 GWSNAX servers
   
*SERVERS
1 GWADM / GWSNAX pair
     
1 application server (for inbound call)
 
DMCONFIG
*DM_LOCAL
1 local domain: SNAX11
   
*DM_REMOTE
1 remote domain: CICSA1
   
*DM_SNACRM
1 CRM: CRM1
   
*DM_SNALINKS
1 LINK: CICSA1
   
*DM_EXPORT
1 service in application server
TUX2
UBBCONFIG
*GROUPS
1 group for 1 GWSNAX server
   
*SERVERS
1 GWADM/GWSNAX pair
 
DMCONFIG
*DM_LOCAL
1 local domain: SNAX21
   
*DM_REMOTE
1 remote domain: CICSA1
   
*DM_SNACRM
1 CRM: CRM2
   
*DM_SNALINKS
1 LINK: CICSA1
   
*DM_EXPORT
1 service in application server
Mainframe
VTAM list
Major node
2 APPC LUs (for two CRMs)
 
CICSA
Resource
2 CONNECTION/SESSION pairs (for two CRMs)
     
DFHDYP program: DYPSAMP
     
TRANSACTION/PROGRAM for DPLC
   
SIT
DFHDYP initialization parameter: DTRPGM=DYPSAMP

Multiple Connections and Multiple Links

Figure 9-3

Overview

The term connection is used for the TCP connection between GWSNAX and CRM, and the term link is used for the SNA connection between CRM and CICS. TMA SNA supports both multiple connections and multiple links simultaneously.

Note: GWSNAXs connect to one CRM must be in different Tuxedo domains.

Multiple Configuration

Table 9-3 Multiple Configuration
Machine
File
Field
Content
TUX1
UBBCONFIG
*GROUPS
2 groups for 2 GWSNAX servers
   
*SERVERS
2 GWADM/GWSNAX pairs
 
DMCONFIG
*DM_LOCAL
2 local domains: SNAX11, SNAX12
   
*DM_REMOTE
4 remote domains: CICSA1, CICSB1, CICSA2, CICSB2
   
*DM_SNACRM
2 CRMs: CRM1, CRM2
   
*DM_SNALINKS
4 LINKs: CICSA1, CICSB2, CICSA2, CICSB2
TUX2
UBBCONFIG
*GROUPS
2 groups for 2 GWSNAX servers
   
*SERVERS
2 GWADM/GWSNAX pairs
 
DMCONFIG
*DM_LOCAL
2 local domains: SNAX21, SNAX22
   
*DM_REMOTE
4 remote domains: CICSA1, CICSB1, CICSA2, CICSB2
   
*DM_SNACRM
2 CRMs: CRM1, CRM2
   
*DM_SNALINKS
4 LINKs: CICSA1, CICSB2, CICSA2, CICSB2
MF
VTAM list
Major node
2 APPC LUs (for two CRMs)
 
CICSA
Resource
2 CONNECTION/SESSION pairs (for two CRMs)
 
CICSB
Resource
2 CONNECTION/SESSION pairs (for two CRMs)


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