MGSL_DLPHYSPARAMS Structure

This structure specifies the functional link layer characteristics of a physical device. This structure is used with the MgslDlGetPhysParams and MgslDlSetPhysParams API functions.

typedef struct _MGSL_DLPHYSPARAMS
{
    ULONG Flags;            /* bitmask of link layer flags */
    ULONG TransmitTimeout;  /* transmit timeout in milliseconds */
    ULONG TxActiveIdle;     /* idle mode between queued tx frames */
    USHORT CtsTransmitDelay; /* cts transmit delay (milliseconds) */
    USHORT InterframeDelay;  /* interframe delay (milliseconds) */
    USHORT RtsDropDelay;     /* rts drop delay (milliseconds) */
    USHORT TurnaroundDelay;  /* turnaround delay (milliseconds) */
} MGSL_DLPHYSPARAMS, *PMGSL_DLPHYSPARAMS;

Fields marked as reserved are reserved for future use and should be set to zero for compatibility.

Flags

The Flags member contains flags that specify functional characteristics of the link.

`DLPHYSFLAG_LOOP_CONTROLLER`	Physical device is a loop controller (primary normal response mode station controlling loop mode secondaries). When this flag is set, the NRM protocol is altered to accommodate loop mode communications.
`DLPHYSFLAG_EXTENDED_ADDRESS`	When set, extended addresses are used on this physical device. Extended addresses have a 0 in the least significant bit of each address byte except the last address byte. When this flag is cleared (default) single byte addresses are used with all 256 combination available.

TransmitTimeout

The time in milliseconds allowed for a frame to be transmitted. This value should be set to a large enough value to allow the maximum size frame to be sent at the selected data rate. When the timeout occurs, the transmitter is reset and the next pending send frame is sent. Transmit timeouts indicate that the transmit data clock is not present or CTS has not gone active.

TxActiveIdle

The transmit idle mode used between frames when sending a group of queued frames. When no more frames are available to send, the idle mode selected in MGSL_PARAMS is used. The TxActiveIdle value is usually set to HDLC_TXIDLE_FLAGS. The idle value in MGSL_PARAMS is usually HDLC_TXIDLE_FLAGS for balanced mode and full duplex normal response mode, otherwise it should be HDLC_TXIDLE_ONES.

The following delays should only be enabled if absolutely necessary.

CtsTransmitDelay

This option specifies a delay (in milliseconds) after Clear To Send (CTS) goes active before a frame is transmitted.

Normally the DCE turns CTS on when it is ready to accept transmit data. In rare cases, a delay is necessary to allow the CTS signal to settle before transmitting. This delay compensates for this situation.

Enabling this delay also allows for the driver to perform software monitoring of CTS in cases where hardware monitoring of CTS and DCD must be disabled.

NOTE:

Incorrectly modifying this value may produce unpredictable results.

InterframeDelay

This value specifies a delay (in milliseconds) between transmitted frames.

Enable this delay to introduce additional flags between transmit frames to accomodate devices that do not support receiving a single flag between frames. This delay can also slow the transmit rate for devices that have problems receiving frames at a high rate.

NOTE:

Incorrectly modifying this value may produce unpredictable results.

RtsDropDelay

This value specifies a delay (in milliseconds) after completion of a send frame before turning RTS (Request to Send) off.

In a switched RTS setup, some equipment requires RTS to stay active for a period of time after a transmit frame completes. This option provides this capability.

NOTE:

Incorrectly modifying this value may produce unpredictable results.

TurnaroundDelay

This value specifies a delay (in milliseconds) between turning RTS (Request to Send) off and turning RTS on.

In a switched RTS setup, RTS is turned on before sending frames, and is turned off after the last available frame is sent. Some environments require a delay after changing the state of RTS for CTS to settle. Enabling this option prevents unexpected transmit behavior caused by attempting to send frames while CTS is in an unsettled state.

NOTE:

Incorrectly modifying this value may produce unpredictable results.

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