DLC_START_LS

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DLCSDLC supports up to 254 concurrent link stations (LSs) on a single port when it operates as a multidrop primary node or a multiple-PU secondary node.

Only one LS can be started when DLCSDLC operates on a point-to-point connection, or when it is a single-PU secondary node on a multidrop connection.

  • The following common link station flags are not supported:
    Item Description
    LSVC LS virtual call is ignored.
    ADDR Address indicator must be set to 1 to indicate that no name-discovery services are provided.
  • The len_raddr_name (length of remote address or name) field must be set to 1.
  • The raddr_name (remote address or name) field is the one-byte station address of the remote node in hexadecimal.
  • The maxif (maximum I-field length) field can be set to any value greater than 0. DLCSDLC adjusts this value to a maximum of 4094 bytes if set too large.
  • The rcv_wind (maximum receive window) field can be set to any value from 1 to 7. The recommended value is 7.
  • The xmit_wind (maximum transmit window) field can be set to any value from 1 to 7. The recommended value is 7.
  • The rsap (remote SAP) field is ignored.
  • The rsap_low (remote SAP low range) field is ignored.
  • The rsap_high (remote SAP high range) field is ignored.
  • The max_repoll field can be set to any value from 1 to 255, inclusive. The recommended value is 15.
  • The repoll_time field is defined in increments of 0.1 second and can be set to any value from 1 to 255. The recommended value is 30, giving a time-out duration of approximately 30 seconds.
  • The ack_time (acknowledgment time) field is ignored.
  • 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 30, giving a time-out duration of approximately 30 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.
  • The following protocol-specific data area must be appended to the generic start LS argument structure (dlc_sls_arg). This structure provides DLCSDLC with additional protocol-specific configuration parameters: 
    
struct   sdl_start_psd
}
  uchar_t    duplex;    /*link station xmit/receive capability */
  uchar_t    secladd;   /* secondary station local address */
  uchar_t    prirpth;   /* primary repoll timeout threshold */
  uchar_t    priilto;   /* primary idle list timeout */
  uchar_t    prislto;   /* primary slow list timeout */
  uchar_t    retxct;    /* retransmit count ceiling */ 
  uchar_t    retxth;    /* retransmit count threshold */
  uchar_t    reserved;  /* currently not used */  
{;
    The protocol-specific parameters are as follows:
    Item Description
    duplex Specifies LS transmit-receive capability. This field must be set to 0, indicating two-way alternating capability.
    secladd Specifies the secondary station link address of the local station. If the local station is negotiable, this address is used only if the local station becomes a secondary station from role negotiation. This field overlays the mpioctl (CIO_START) poll address variable, poll_addr.
    prirpth Specifies primary repoll threshold. This field specifies the number of contiguous repolls that cause the local primary to log a temporary error. Any value from 1 to 100 can be specified. The recommended value is 10.
    priilto Specifies primary idle list time out. If the primary station has specified the Hold Link on Inactivity parameter and then discovers that a secondary station is not responding, the primary station places that secondary station on an idle list. The primary station polls a station on the idle list less frequently than the other secondary stations to avoid tying up the network with useless polls. This field sets the amount of time (in seconds) that the primary station should wait between polls to stations on the idle list. Any value from 1 to 255, inclusive, may be specified. The recommended value is 60, giving a time-out duration of approximately 60 seconds.
    prislto Specifies primary slow list time out. When the primary station discovers that communication with a secondary station is not productive, it places that station on a slow list. The primary station polls a station on the slow list less frequently than the other secondary stations to avoid tying up the network with useless polls. This field sets the amount of time (in seconds) that the primary station should wait between polls to stations on the slow list. Any value from 1 to 255, inclusive, can be specified. The recommended value is 20, giving a time-out duration of approximately 20 seconds.
    retxct Indicates retransmit count. This field specifies the number of contiguous information frame bursts containing the same data that the local station retransmits before it declares a permanent transmission error. Any value from 1 to 255, inclusive, can be specified. The recommended value is 10.
    retxth Indicates retransmit threshold. This field specifies the maximum number of information frame retransmissions allowed as a percentage of total information frame transmission (sampled only after a block of information frames has been sent). If the number of retransmissions exceeds the specified percentage, the system declares a temporary error. Any value from 1 to 100% can be specified. The recommended value is 10%.