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 for the token ring contains the four least significant bytes of the desired six-byte group address. Only bits 1 through 31 are valid. Bit 0 is ignored. The most significant two bytes are automatically compared for 0xC000 by the adapter.
  • The func_addr_mask (functional address mask) field must be the logical OR operation with the functional address on the adapter, which allows packets that are destined for specified functions to be received by the local adapter. Only bits 1 through 29 are valid. Bits 0, 30, and 31 are ignored. The most significant two bytes of the full six-byte functional address are automatically compared for 0xC000 by the adapter.

    The following is an example of a Network Basic Input/Output System (NetBIOS) functional address:

    
To select the NETBIOS functional address of 0xC000_0000_0080,
the functional address mask is set to 0x0000_0080.
    Note: DLCTOKEN does not check to determine whether a received packet was accepted by the adapter due to a preset network address, group address, or functional address.
  • The max_ls (maximum link stations) field cannot exceed a value of 255.
  • The following common SAP flags are not supported:
    Item Description
    ENCD Specifies a synchronous data link control (SDLC) serial encoding.
    NTWK Indicates a teleprocessing network type.
    LINK Indicates a teleprocessing link type.
    PHYC Indicates 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 and 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 (that is, the ADDR flag is set to 1), DLCTOKEN 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 null SAP (0x00) or 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 DLCTOKEN to enable a SAP.