DLC_ENABLE_SAP

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 field is a 6-byte value as specified in the draft IEEE Standard 802.3 specifications. Octet grp_addr[0] specifies the most significant byte and octet grp_addr[5] specifies the least significant byte. Each octet of the address field is transmitted, least significant bit first. Group addresses sometimes are called multicast addresses. An example of an group address follows:

  
  0x0900_2B00_0004
  

  Note: No checks are made by the DLCETHER device manager as to whether a received packet was accepted by the adapter due to a preset network address or group address.
• The max_ls (maximum link station) field cannot exceed a value of 255.
• The following common SAP flags are not supported:

  Item	Description
  ENCD	Indicates 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 field is set to 0. When resolve procedures are used (that is, the ADDR flag is set to 1), DLCETHER 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 the DLCETHER device manager to enable a SAP.