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Maximum concurrnet User supported by CA GEN multi socket Listener

  • 1.  Maximum concurrnet User supported by CA GEN multi socket Listener

    Posted 05-29-2017 08:47 AM

    In our organisation we are trying to connect our offhost application (built using CA GEN) through HIS server (installed on Windows Sever) which connects to further CICS regions in mainframes through VTAM.


    We are trying to get the HIS connectivity replaced with CA Gen multi socket Listener software.  This would mean that our application (installed on a desktop) would be directly connecting to mainframes through CA GEN multi socket listeners instead of routing through HIS Server.


    Query is to check if there is any limitation on number of concurrent Users that could be parallel acquire connection and serviced by CA GEN multi Socket Listener. Are these dependent on some parameters which required to be configured?

  • 2.  Re: Maximum concurrnet User supported by CA GEN multi socket Listener

    Broadcom Employee
    Posted 05-30-2017 10:13 PM

    Hi Vikas,

    I believe the TIML concurrent user limit is effectively the socket limit for Listener which is set by parameter NUMSOCK in the EZACONFG file (IBM z/OS V1R9 Communications Server: IP CICS Sockets Guide - United States)

    That defaults to 50 and we normally recommend a value of 100 as a starting point (I understand the max is 999)


    Additional Information I found:

    • Each server only uses 1 socket, the listener gets a socket for each server out of a pool up to NUMSOCK. The sockets are released back into the pool (and reused) as servers complete. If the pool is exhausted the requests are queued in waiting up to the number specified in BACKLOG. You will need to obtain information/statistics from SOCKETSAPI and TCPIP to see this.
    • When the TIML listener terminates, it reports the message ‘MOST SOCKETS USED: XXXX’ which is the highest socket number used. If this number is consistently NUMSOCK-2 and you are hitting the BACKLOG often, you may want to increase the NUMSOCK value.


    Hope that helps

    Adding SME Letha johle05 for other input