# Maximum EXCI Sessions

The IBM default is a maximum of 100 EXCI sessions for each address space.

This limit applies to all CICS and Substation ES regions. This is a runtime limit and is checked by IBM at the EXCI Session Allocation time.
Note: If Substation ES is interfacing with more than one CICS, the combined total number of EXCI sessions in that Substation ES must be less than 100.

A message similar to the following one is displayed in Substation ES when the limit is exceeded:

    SXC3101E CICS EXCI Call Error,TRAN:{tranid},NetName:{EXCI Name},
    							CICS IRC Code:56 X'38' Subreason2:-2147483548
    							RC:8 RSN:3101N:3101
       ID3: 0002 16          608 {CICS Name} {Program Name}

The IRC command return code `56` is a NO_FREE_LACBE_FOR_LOGON code, and indicates that there is "No free LACBE for Logon".

Code 608, one of the response and reason calls returned on the EXCI calls, is an IRC_LOGON_FAILURE code.

Together, these two codes indicate that the 100 pipe limit for each address space has been reached. Each CICS address space can have a maximum of 100 pipes connected, whether this is to one CICS or several CICS regions.

For more information, see the IBM documentation on CICS Transaction Server for z/OS, in particular the section on EXCI pipe allocation in Installation Guide.

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