DLC_START_LS

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This section explains the ioctl subroutine argument structure for starting a link station.

The ioctl subroutine argument structure for starting a link station, dlc_sls_arg, has the following specifics:

  • The following common link station flags are not supported:
    Item Description
    STAT Indicates a station type for SDLC.
    NEGO Indicates a negotiable station type for SDLC.
  • The raddr_name (remote address or name) field is used only for outgoing calls when the DLC_SLS_LSVC common link station flag is active.
  • The maxif (maximum I-field length) field can be set to any value greater than 0. The DLC FDDI device manager adjusts this value to a maximum of 4077 bytes if set too large. See the DLC FDDI frame encapsulation figure (FDDI Data Packet) for more details.
  • The rcv_wind (receive window) field can be set to any value from 1 to 127, inclusive. The recommended value is 127.
  • The xmit_wind (transmit window) field can be set to any value from 1 to 127, inclusive. The recommended value is 26.
  • The rsap (remote SAP) 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.
  • The max_repoll field can be set to any value from 1 to 255, inclusive. The recommended value is 8.
  • The repoll_time field is defined in increments of 0.5 seconds and can be set to any value from 1 to 255, inclusive. The recommended value is 2, giving a time-out duration of 1 to 1.5 seconds.
  • The ack_time (acknowledgment time) field is defined in increments of 0.5 seconds, and can be set to any value from 1 to 255, inclusive. The recommended value is 1, giving a time-out duration of 0.5 to 1 second.
  • The inact_time (inactivity time) field is defined in increments of 1 second and can be set to any value from 1 to 255, inclusive. The recommended value is 48, giving a time-out duration of 48 to 48.5 seconds.
  • The force_time (force halt time) field is defined in increments of 1 second and can be set to any value from 1 to 16383, inclusive. The recommended value is 120, giving a time-out duration of approximately 2 minutes.
  • A protocol-specific data area must be appended to the generic start link station (LS) argument (dlc_sls_arg). This structure provides DLC FDDI with additional protocol-specific configuration parameters: 
    
struct fdl_start_psd
{
 uchar_t       pkt_prty;        /* ring access packet priority */
 uchar_t       dyna_wnd;        /* dynamic window increment    */
 ushort_t      reserved;        /* currently not used          */
};

    The protocol-specific parameters are:

    Item Description
    pkt_prty Specifies the ring-access priority that the user wishes to reserve on transmit packets. Values of 0 to 7 are supported, where 0 is the lowest priority and 7 is the highest priority.
    dyna_wnd Network congestion causes the local transmit window count to automatically drop to a value of 1. The dynamic window increment specifies the number of consecutive sequenced packets that must be acknowledged by the remote station before the local transmit window count can be increment. This allows a gradual increase in network traffic after a period of congestion. This field can be set to any value from 1 to 255; the recommended value is 1.