Changing the TRANSFR Parameter

If you change the TRANSFR parameter in one NCP in a network, all other NCPs in that network require the same change. If you cannot easily change the NCP TRANSFR parameter, use the following reverse process to calculate the maximum RU size for use by IBM® Connect:Direct®:

  1. Multiply the NCP TRANSFR parameter by the NCP BFRS value. The result is the maximum amount of data that NCP can receive.
  2. Subtract 24 bytes for required NCP overhead (BFRPAD).
  3. Subtract 29 bytes for the request/response header.
  4. Find the next lowest RU size value in the table on Understanding RU Sizing. This value is the largest RU that you can specify for use by IBM Connect:Direct.

    The amount of data VTAM can receive from the NCP is determined by the product of MAXBUFRU times UNITSZ. This value must be less than or equal to the amount specified on the IOBUF buffer pool allocation parameters in the ATCSTRxx start options list of VTAMLST.