gsm Cs V42 T402 Ack Delay Timer

This attribute specifies the maximum amount of time that the IWF may wait following the receipt of any frame requiring a reply before it initiates transmission of an appropriate reply in order to ensure that the reply frame is received by the remote error-correcting entity prior to expiration of the T401 timer of the remote error-correcting entity. Since information about the T402 timer is not carried in the Exchange Identification (XID) negotiations at call setup, both sides operate with different timer values. If this timer expires, then the reply that would have been returned prior to its expiration is not sent. The performance of the data link layer can be impacted by the value of this timer as retransmissions of frames occur on expiry of timer T401. For better performance, a value of t402AckDelayTimer (T402) equal to half the value of t401AckTimer (T401) is recommended. Changes to this attribute do not effect existing calls.