Set PROTOCOL.INI Params for DLC Protocol 3270 Emulation (98463)

SUMMARY

If you have Ethernet and the IBM 3270 Personal Communication product, running token ring adapters on a LAN Manager file server, and you want to use the IBM LAN Support Program and DLC protocol to obtain a 3270 emulation, you must first correctly set several PROTOCOL.INI parameters.

Failure to set these can cause communication errors, and a configuration on which this occurred is described at the end of this article.

MORE INFORMATION

On a workstation currently running with the IBM PCLP, open the CONFIG.SYS file and find DXME0MOD.SYS. There are normally two parameters. The first, immediately following the driver, is the 12-digit address (enclosed in double quotation marks) of a locally administered address (LAA). If this is present, set it to the same address by using the NETADDRESS parameter in the ELNK section of PROTOCOL.INI.

The next DXME parameter to be considered is the 'xmit_swap0 parameter. It is the third parameter following the drivername and determines whether destination address bits are swapped, and whether 802.3 or Ethernet DIX 2.0 frames are sent. It has four settings:

   IBM LAN Support
      0 - transmit 803.2 frames and swap address bits (default)
      1 - transmit Ethernet DIX frames and swap address bits
      2 - transmit 802.3 frames and don't swap address bits
      3 - transmit Ethernet DIX frames and don't swap address bits

You can achieve the same combinations by using the SWAP and USEDIX parameters in the MSDLC section.

The following is a sample configuration on which failure to set these parameters after inserting 3Com adapters causes communications errors 690 and 510:

Server:      IBM 9595 and EtherLink II MC
             LAN Manager 2.1

Workstation: IBM PSVP with MS-DOS 5.0
             Windows operating system 3.1
             LAN Manager 2.1 enhanced workstation

Protocols:   NetBEUI and DLC (Beta 5 March 93)

Gateway:     MS-DOS 5.0 with Personal Communication V3 IBM