DLC_ENABLE_SAP

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This section explains the ioctl subroutine argument structure for enabling a SAP.

The ioctl subroutine argument structure for enabling a SAP, dlc_esap_arg, has the following specifics:

  • The grp_addr (group address) field contains the full six-byte group address with the individual control bits, group control bits, universal control bits, and local control bits located in the most significant bit positions of the first (leftmost) byte.
  • The func_addr_mask (functional address mask) field is not supported.
  • The max_ls (maximum link stations) field cannot exceed a value of 255.
  • The following common SAP flags are not supported:
    Item Description
    NTWK Indicates a teleprocessing network type.
    LINK Indicates a teleprocessing link type.
    PHYC Represents a physical network call (teleprocessing).
    ANSW Indicates a teleprocessing autocall and autoanswer.
  • Group SAPs are not supported, so the num_grp_saps (number of group SAPs) field must be set to 0.
  • The laddr_name (local address or name) field and its associated length are only used for name discovery when the common SAP flag ADDR is set to 0. When resolve procedures are used (the ADDR flag set to 1), DLC FDDI obtains the local network address from the device handler and not from the dlc_esap_arg structure.
  • The local_sap (local service access point) field can be set to any value except the null SAP (0x00) or the name-discovery SAP (0xFC). Also, the low-order bit must be set to 0 (B`nnnnnnn0') to indicate an individual address.
  • No protocol-specific data area is required for DLC FDDI to enable an SAP.