A session address space is an address space used to issue VTAM® macroinstructions that establish sessions (OPNDST or OPNSEC). A session address space is either an ACB address space or an associated address space. The RECEIVE OPTCD=SPEC, RESETSR, SESSIONC (except when used to send a request rejected response to BIND), and SEND macroinstructions can be issued only in a session address space. If one of these macroinstructions is issued in an address space other than the address space in which the corresponding session was established, the macroinstruction is posted complete with (RTNCD,FDB2)=(X'14',X'24'), indicating a logic error and an address space ID (ASID) mismatch.