Unless you are using ECI over TCP/IP exclusively (see Using ECI over TCP/IP), you must install APPC connections to the Clients. The connections can be single- or parallel-session links.
You can use CEDA DEFINE and INSTALL commands to create static definitions.
For information about defining APPC connections to non-System/390® systems, see Resource definition for communication with non-System/390 systems.
The preferred method of installing APPC connections to Clients is to use autoinstall. If you use autoinstall, you must create some suitable CONNECTION and SESSIONS template definitions, if these do not already exist.
For information about autoinstall and defining templates, see your CICS® on System/390 Resource Definition Guide. For information about customizing your autoinstall user program to handle APPC connections, see your CICS on System/390 Customization Guide.
A connection is autoinstalled on CICS on System/390 when the Client initiates communication. (This could be, for example, when the end-user issues a cicscli /s=servername command to connect to the CICS on System/390 server, a cicsterm /s=servername command to start a 3270 emulator session, or when an ECI or EPI program is started on the Client.)
TCP/IP communication between Clients and CICS on System/390 is supported in two ways:
This section applies to:
TCP/IP via TCP62 requires the AnyNet feature of VTAM®. The other System/390 software you require depends on the level of VTAM you are running. Table 42 shows the acceptable software combinations.
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Enabling CICS to communicate with a Client using TCP/IP via TCP62 requires actions on z/OS, CICS, VTAM, and the Client workstation.
On z/OS, you must:
ABHTCP VBUILD TYPE=TCP,
CONTIMER=25,
DGTIMER=40,
DNSUFX=HURSLEY.IBM.COM,
EXTIMER=5,
IATIMER=60,
PORT=397,
TCB=10,
TCPIPJOB=TCPIP
ABH1GRP GROUP ISTATUS=ACTIVE
ABH1LINE LINE ISTATUS=ACTIVE
ABH1PU PU ISTATUS=ACTIVE
This defines the AnyNet interface between TCP/IP and VTAM. For further information about how to do this, see the Guide to SNA over TCP/IP manual, SC31-6527.
AP23ACDS VBUILD TYPE=CDRSC
TCPCDGRP GROUP
IYCNT999 CDRSC ALSLIST=ABH1PU,MODETAB=MTCICS
This defines the remote Client device and instructs VTAM to route any session requests through the TCP/IP Physical Unit (ALSLIST).
DSN=PP.ADLE370.OS390R2.SCEERUN
This library should be present by default.
On CICS, you must:
On the Client workstation, you must install TCP62 support and configure the Client initialization (INI) file.
This section applies only to CICS Transaction Server for z/OS, Version 2 Release 2 and later.
Enabling ECI over TCP/IP requires actions on CICS and the Client workstation.
On CICS, you must:
A TCPIPSERVICE for ECI over TCP/IP requires SOCKETCLOSE(NO) to be specified. The recommended method to achieve a timeout for a task initiated through ECI over TCP/IP is to specify an RTIMOUT value on the mirror transaction. The standard mirror transaction, CPMI, is defined with profile DFHCICSA, which has RTIMOUT(NO). This means that long-running mirrors will wait indefinitely for data unless you customize the RTIMOUT value for the mirror transaction.
The supplied TCPIPSERVICE definition specifies an attach-time security level of VERIFY and a TCP/IP port number of 1435. If you want some of your Clients to use LOCAL security and others to use VERIFY, you must create two TCPIPSERVICE definitions. The two definitions should have different security attributes and must listen on different ports. In each Client initialization file, specify that the Client should use the port for the appropriate security level.
On the Client workstation, you must:
SECTION SERVER = ECICLNT
DESCRIPTION=TCP/IP Server
UPPERCASESECURITY=N
USENPI=N
PROTOCOL=TCPIP
NETNAME=hostname.example.com
PORT=1435
CONNECTTIMEOUT=0
TCPKEEPALIVE=N
ENDSECTION
When setting up Clients to use ECI over TCP/IP, bear the following in mind:
ECI over TCP/IP support includes support for conversation-level and connection-level ping. These ping flows are initiated from CICS if a Client becomes unresponsive, but only if the mirror transaction is running with a profile that specifies a timeout. The default mirror does not have a timeout. To enable ping support you must use a mirror profile that specifies a timeout. If you don’t, and a Client becomes disconnected due to a connection failure, any current conversations with the Client could be suspended indefinitely.
When a timeout occurs, CICS does the following:
If a connection fails during an ECI extended conversation, CICS detects this when the ping timeout processing occurs. The conversation is abended.
Port sharing, used as a method of load balancing in a CICSplex, is supported for TCP/IP-connected Clients.
When a Client is installed into CICS, the install request is routed to a particular CICS region. The sockets domain in that region allocates an ephemeral port for use with the Client during the rest of the time for which it is installed. The ephemeral port is not shared, so an affinity between the Client and the CICS region on which it is installed is established. Until the client is uninstalled or the connection fails (forcing the Client to be re-installed), all subsequent work is routed to the correct CICS region through the unshared ephemeral port.