IBM Understanding CTRC Channel Functionality in Networking

Overview of IBM Networking

Cisco Transaction Connection

The CTRC software feature provides the following functionality:

•CTRC allows Cisco routers to use the intersystem communication (ISC) protocol to provide a gateway between Customer Information Control System (CICS) clients (also known as common clients) running under Windows or UNIX on TCP/IP networks and CICS online transaction monitoring systems on IBM hosts.

•CTRC supports two interfaces to common clients: the Extended Call Interface (ECI), which lets non-CICS client programs call CICS transactions, and the Extended Presentation Interface (EPI), which lets distributed applications call CICS transactions that were originally accessed via 3270 terminals.

•CTRC supports the ability to configure routes for CICS transaction. Each transaction can be routed to a specific CICS region.

•In addition to its CICS-related functionality, CTRC includes the feature previously known as Cisco Database Connection (CDBC), which allows Cisco routers to use IBM's distributed relational database architecture (DRDA) protocol to provide a gateway between client workstations running Open DataBase Connectivity (ODBC) compliant applications on TCP/IP networks and IBM DB2 databases on SNA networks. ODBC is a call-level interface developed by Microsoft Corporation that allows a single application to access database management systems from different vendors using a single interface. SNA is a large, complex, feature-rich network architecture developed by IBM.

•CTRC adds support for TCP/IP passthrough, allowing the use of a TCP/IP network, rather than a SNA network, between a Cisco router and a DB2 database if the database version supports direct TCP/IP access.

•To match functionality provided in DRDA over TCP/IP, CTRC adds support for Password Expiration Management (PEM) in SNA networks where PEM is supported.

•CTRC supports the following MIBs:

–CISCO-DATABASE-CONNECTION-MIB.my - 93

–CISCO-TRANSACTION-CONNECTION-MIB.my - 144

For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB website on Cisco.com.

CTRC and CICS

CTRC is a Cisco IOS software feature that is available in two environments:

•CICS

•DB2

When a router is configured to use CTRC for communications with CICS systems, the router converts ISC packets over TCP/IP to ISC packets over Advanced Program-to-Program Communications (APPC) LU 6.2 and then routes them to the appropriate CICS region. CTRC converts CICS client messages received via TCP/IP to SNA messages and uses Cisco SNA Switching Services to send them to the host.

CTRC runs as a TCP/IP daemon on the router, accepting ISC client connections over TCP/IP. When a client connects to a CICS region on an IBM mainframe host, CTRC allocates an APPC conversation over SNA to an IBM server and acts as a gateway between ISC over TCP/IP and ISC over APPC.

Figure 109 illustrates how CTRC lets CICS client applications on TCP/IP networks interact with CICS transaction monitoring systems on IBM hosts.

	Cisco IOS Bridging and IBM Networking Configuration Guide
BC-240	78-11737-02