This section describes how to define connections for use by non-CICS® programs using the external CICS interface (EXCI) to link to CICS server programs. The definitions required are similar to those needed for MRO links between CICS systems. Each connection requires a CONNECTION and a SESSIONS definition.
Because EXCI connections are used for processing work from external sources, you must not define any SEND sessions.
EXCI connections can be defined as "specific" or "generic". A specific EXCI connection is an MRO link on which all the RECEIVE sessions are dedicated to a single user (client program). A generic EXCI connection is an MRO link on which the RECEIVE sessions are shared by multiple users. Only one generic EXCI connection can be defined on each CICS region.
On definitions of both specific and generic connections, you must:
Figure 41 shows the definition of a specific EXCI connection.
DEFINE
CONNECTION(EIP1) local name for connection
GROUP(groupname) groupname of related definitions
NETNAME(CLAP1) user name on INITIALIZE_USER command
ACCESSMETHOD(IRC)
PROTOCOL(EXCI)
CONNTYPE(Specific) pipes dedicated to a single user
INSERVICE(YES)
ATTACHSEC(LOCAL)
DEFINE
SESSIONS(csdname) unique csd name
GROUP(groupname) same group as the connection
CONNECTION(EIP1) related connection
PROTOCOL(EXCI) external CICS interface
RECEIVEPFX(<)
RECEIVECOUNT(5) 5 receive sessions
SENDPFX leave blank
SENDCOUNT leave blank
For a specific connection, NETNAME must be coded with the name of the user program that will be passed on the EXCI INITIALIZE_USER command. CONNTYPE must be Specific.
Figure 42 shows the definition of a generic EXCI connection.
DEFINE
CONNECTION(EIP2) local name for connection
GROUP(groupname) groupname of related definitions
ACCESSMETHOD(IRC)
NETNAME() must be blank for generic connection
INSERVICE(YES)
PROTOCOL(EXCI)
CONNTYPE(Generic) pipes shared by multiple users
ATTACHSEC(LOCAL)
DEFINE
SESSIONS(csdname) unique csd name
GROUP(groupname) same group as the connection
CONNECTION(EIP2) related connection
PROTOCOL(EXCI) external CICS interface
RECEIVEPFX(<)
RECEIVECOUNT(5) 5 receive sessions
SENDPFX leave blank
SENDCOUNT leave blank
For a generic connection, NETNAME must be blank. CONNTYPE must be Generic.
You can install new MRO and EXCI connections dynamically, while CICS is fully operational--there is no need to close down interregion communication (IRC) to do so. Note that CICS commits the installation of connection definitions at the group level--if the install of any connection or terminal fails, CICS backs out the installation of all connections in the group. Therefore, when adding new connections to a CICS region with IRC open, ensure that the new connections are in a group of their own.
You cannot modify existing MRO (or EXCI) links while IRC is open. You should therefore ensure, when defining an MRO link, that you specify enough SEND and RECEIVE sessions to cater for the expected workload.
For further information about installing MRO links, see the CICS Resource Definition Guide.