Many factors and parameters affect SDLC Acronym for Synchronous Data Link Control. A low-level communications protocol for synchronous communications. performance. To optimize the performance, make sure the following parameters are selected. The parameters in the Microsoft SNA gateway Connection Properties dialog box must match the corresponding PU parameters defined in VTAM on the mainframe.
From the Microsoft SNA gateway Connection Properties dialog box:
MAXBTU corresponds to the MAXDATA VTAM parameter. The default value of 265 in the Microsoft SNA gateway can be increased to 1033 in order to improve performance.
The Duplex parameter must be set to FULL if possible and supported by all equipment in the connection environment. This will allow simultaneous bidirectional communications on the SDLC circuit, improving data transfer performance. Transmission and flow control acknowledgements can be sent without interfering with data transmission. Set this parameter to FULL only if Constant RTS is set under the Link Services properties dialog box.
Leave the Data Rate parameter set to the default value of HIGH. This governs the rate at which data is transmitted between the SDLC adapter and the external communications equipment. The Barr T1-SYNC for SNA device driver is capable of utilizing the high Data Rate, but can be limited by the external communications hardware (modem Short for modulator/demodulator. A communications device that enables a computer to transmit information over a standard telephone line., CSU/DSU, and so on.)
From the Barr T1-SYNC for SNA Link Service dialog box:
Set the DATMODE Data mode to be used to transmit data. to FULL to allow bidirectional communications with the mainframe. Set the DATMODE parameter in the VTAM PU definitions to FULL as well.