An IPIC connection can use port sharing or Sysplex Distributor to connect to a cluster of
CICS® regions. The CICS
regions must be configured with the same programs, transactions, and security settings. These
connections can be configured to use TLS.
Before you begin
You should be familiar with the information on CICS IPIC high availability, which describes how IPIC HA connections are
established, how high availability is maintained and how the HA reconnection feature works.
A shared TCP/IP port must be configured by using z/OS
TCP/IP port sharing or Sysplex Distributor, which each of the CICS regions in the cluster then listens on.
About this task
This task illustrates how to configure two IBM z/OS Connect servers (zosConn1 and
zosConn2) each with an IPIC connection to a cluster of two CICS regions (CICS-A and CICS-B). The two CICS
regions are both configured with a generic TCPIPSERVICE that listens on shared port 2222. CICS-A is configured with a specific TCPIPSERVICE that listens on
port 1091 and CICS-B is configured with a specific
TCPIPSERVICE that listens on port 1092. Figure 1
illustrates the connections that are established on the specific ports. In normal operation,
zosConn1 is connected to CICS-A and
zosConn2 is connected to CICS-B. Each
connection can fail over to the other CICS region if one CICS regionCICS fails.
Each CICS region requires a separate IPCONN definition for
each IBM z/OS Connect Server that can connect to it. Table 1 details the required settings.
Figure 1. IPIC HA connections to CICS-specific ports
Table 1. Example parameters for IPIC
HA configuration
IBM z/OS Connect Server
IPIC connection reference ID
zosConnectNetworkid, zosConnectApplid
CICS region
Specific TCPIPSERVICE port number
IPCONN Networkid, Applid
zosConn1
cicsConn
NET1, ZCONN1
CICS-A
1091
NET1, ZCONN1
CICS-B
1092
NET1, ZCONN1
zosConn2
cicsConn
NET2, ZCONN2
CICS-A
1091
NET2, ZCONN2
CICS-B
1092
NET2, ZCONN2
Note:
When using predefined IPCONNs with IPIC HA, each CICS
region must have a separate IPCONN definition for each
zosconnect_cicsIpicConnection definition in each IBM z/OS Connect Server.
Within a sysplex, each IPIC connection that is defined in z/OS Connect must have a unique Networkid.APPLID identifier
that is specified by using the zosConnectApplid and
zosConnectNetworkid attributes on the
zosconnect_cicsIpicConnection element. In CICS, these values must match the Applid and
Networkid parameters in the IPCONN definition.
You can share a zosconnect_cicsIpicConnection element definition between z/OS Connect servers only if you use autoinstalled IPCONNs
and do not specify the zosConnectApplid and zosConnectNetworkid
attributes on the element definition.
Procedure
Configure the connections in z/OS Connect.
Perform the following steps to configure each z/OS Connect IPIC definition.
Define a zosconnect_cicsIpicConnection element. Set
sharedPort="true" and specify the shared port in the port
attribute.
The shared port is the port number that is configured in TCP/IP port sharing or sysplex
distributor, which the CICS regions listen on.
If using predefined IPCONNs in CICS, specify
the zosConnectApplid and zosConnectNetworkid attributes to
uniquely identify this specific connection. If using auto-installed IPCONNs, specifying these
attributes is optional, and if they are not specified, names are automatically generated by CICS. Do not set the cicsApplid and
cicsNetworkid attributes; these attributes are ignored by CICS when using a shared port.
For example, in the server configuration file for zosConn1 specify:
For example, configure a generic TCPIPSERVICE for port 2222 on CICS-A and CICS-B, and a specific TCPIPSERVICE on CICS-A for port 1091 and a specific TCPIPSERVICE on CICS-B for port 1092.
Optional: If using predefined IPCONNs, define an IPCONN for each
zosconnect_cicsIpicConnection definition in each z/OS Connect Server that can connect to that CICS region.
In the IPCONN definitions, the values of the Applid and
Networkid parameters must match the values of the
zosConnectApplid and zosConnectNetworkid attributes on the
corresponding zosconnect_cicsIpicConnection element in
the server configuration file.
For example, on both CICS-A and CICS-B, define two IPCONNs with
Networkid.APPLIDs of NET1.ZCONN1 and NET2.ZCONN2.
Optional: Configure a reconnect interval to periodically rebalance connections.
For example, if CICS-A and CICS-B are on different LPARS, to configure zosConn1 to
preferentially connect to CICS-A and
zosConn2 to preferentially connect to CICS-B, and for connections to be rebalanced every 30 minutes, update the IPIC connection
definitions to add those preferences. If a time unit is not specified for the
reconnectInterval, the time is in milliseconds. In the
server configuration file for zosConn1 specify:
When a connection to CICS is established, message
BAQR0680I shows the IP address of the specific port for that CICS region. If the preferredSpecificHost is specified as a DNS address,
ensure that the DNS name is for this IP address. For example,
BAQR0680I: CICS connection cicsConn established to host 192.0.3.1 on port 1091 with 100 sessions.
If
there is more than one CICS region on any LPAR listening on
the shared port, to specify a preference, set the preferredSpecificPort attribute
to specify the preferred CICS region.
Note: From z/OS Connect V3.0.57, if the preferred CICS region is on the same LPAR as the z/OS Connect Server, you can specify
preferredSpecificHost="local". For more information, see Setting preferredSpecificHost="local".
