AMC1
ACNS.B.DLS.B1.105 Transport Layer Requirements
ED Decision 2013/031/R
The ATN End System of the data link aircraft equipment should comply with the Transport Protocol Class 4 specified in ICAO Document 9705 (Edition 2), Sub-volume V, section 5.5.2.
The data link aircraft equipment should implement Transport Protocol Class 4 parameter settings in accordance with the following table:
|
Scope |
Parameter |
Definition |
Value |
|
Inactivity |
Inactivity time (I) |
A bound for the time after which a transport entity will, if it does not receive a Transport Protocol Data Unit (TPDU), initiate the release procedure to terminate the transport connection. |
360 sec |
|
Re-transmission |
Retransmission time (T1) |
A bound for the maximum time the transport entity will wait for acknowledgement before re-transmitting a TPDU. The retransmission time is adaptive. |
Initial value 30 sec |
|
|
Maximum Retransmission (N) |
Maximum number of TPDU retransmissions. |
7 |
|
Window |
Window time (W) |
A bound for the maximum time a transport entity will wait before retransmitting up-to-date window information. |
120 sec |
|
Flow Control |
Local Acknowledgement delay (Al) |
A bound for the maximum time which can elapse between the receipt of a TPDU by the local transport entity from the network layer and the transmission of the corresponding acknowledgement. |
1 sec |
Aircraft data link systems must use Transport Protocol Class 4 as defined by ICAO Doc 9705. Key parameters include a 360-second inactivity timeout, adaptive retransmission starting at 30 seconds (max 7 retries), 120-second window time, and a 1-second local acknowledgement delay. These settings ensure reliable airborne communication and navigation.
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
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