Mainframe-based communications support provides transport-level functionality. Depending on the mainframe communications software installed, Gateway-Library uses SNA or TCP/IP for z/OS.
For SNA environments, you can use the SNA General Trace Facility (GTF) files to trace SDLC/SNA traffic between Gateway-Library and the mainframe. The IBM TAP utility extracts this information.
For CICS TCP/IP environments, you can use the Netstat facility to check the status of TCP/IP connections, as well as to deactivate them if problems occur.
You can use the TCP/IP trace facility to trace traffic between DirectConnect for z/OS Option and the mainframe.
For CICS, Gateway-Library tracing stores information on the TDS traffic between the mainframe and server in the VSAM ESDS file, SYTDLOG1. This information includes any errors detected in the traffic.
Some TD calls fill up internal TDS buffers before sending them out to the network. For example, a TDSNDROW or TDSNDMSG call does not cause execution of a corresponding CICS EXEC SEND call unless the TDS buffer becomes full.
WARNING! To avoid losing records, periodically archive or delete the trace records on SYTDLOG1. Trace records append to this file until it is full, when it rejects any further records.
