IDERTout

note-icon Note:

Beginning in version 11.0, Storage Redirection uses the USB-R protocol rather than the IDE-R protocol. The struct name has not been changed so as to preserve backwards compatibility.

This structure is used to pass time-out parameters when establishing a Storage Redirection session. The parameters in this structure determine when either Intel AMT or the console will drop a Storage Redirection session because of a timeout. If the values you choose are too restrictive, you may experience unnecessary timeouts under slow network conditions; if they are too lax, the system will not quickly respond when a network connection or other issue has occurred.

This structure is used to determine the time span between firmware-to-client and between client-to-firmware heartbeats, which keep the connection alive. It also determines the amount of time that each end of the connection is willing to wait for a hearbeat if it does not arrive on schedule. The struct contains the following variables:

 

typedef struct {

    unsigned short rx_timeout;

    unsigned short tx_timeout;

    unsigned short hb_timeout;

} IDERTout;

 

 

Field

Value or Description

rx_timeout

The firmware receive timeout, in milliseconds.

While a Storage Redirection session is open, the client periodically sends heartbeat messages to make sure that the firmware’s receive timeout does not expire. If the firmware receives no messages (including heartbeat messages) from the client for the duration of the timeout, it will shut down the Storage Redirection session. (For heartbeat messages sent in the other direction, from the firmware to the client, see the next field.)

Minimum value: 10000

Maximum value: 65535

Default value: 30000

 

Note:

The frequency of the heartbeat messages is determined by the HB_Factor that you add to the client’s .ini File. HB_Factor is the number of heartbeats that need to be missed in order for this timeout to trigger; in other words, the interval between heartbeat messages sent from the client to the firmware is determined by the following equation:

Client heartbeat interval = rx_timeout / HB_Factor

The default value of the HB_Factor is 3, so the default interval between heartbeat messages is 3333.3 ms (thanks to the default timeout of 10000 ms).

hb_interval

The firmware heartbeat interval.

This field determines the behavior of heartbeat messages going in the opposite direction of those handled in the rx_timeout field above: from the firmware to the client, rather than the reverse.

The value in this field is the number of milliseconds between heartbeat messages sent by the firmware.

If the value is non-zero, it should never be set to less than 100. Depending on network conditions, an even longer interval may be required. The recommended value is at least 1000 (one second).

Since a vPro Gateway server (MPS) has a 30-second heartbeat, redirection sessions over an MPS should have a heartbeat interval that is less than 30 seconds to avoid sessions halting prematurely.

A value of 0 in this field means that no heartbeat messages should be sent, in which case the client will send USB-R keep-alive ping messages to the firmware when there is no activity to determine if it is still alive.

Minimum value: 0

Maximum value: 65535

Default value: 10000

 

Note:

The client will set its receive timeout based on the value of the Timeout_Factor that you add to its .ini File. Timeout_Factor is the number of heartbeats that need to be missed in order for the timeout to trigger; in other words, the client’s receive timeout is determined by the following equation:

Client receive timeout = hb_interval * Timeout_Factor

The default value of the Timeout_Factor is 3, so the default client receive timeout is 15000 ms (thanks to the default hb_interval of 5000 ms).

tx_timeout

The firmware’s command transmit timeout. This is the number of milliseconds the firmwares waits when sending out an IDE command. If the firmware does not receive a response from the client to the command within the specified amount of milliseconds, the firmware will close the Storage Redirection session. A value of 0 means that no command transmit timeout is used.

Minimum value: 0

Maximum value: 65535

Default value: 0

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