Home' RTCA Documents for Review : DO-262D Contents Appendix E
© RTCA, 2018
ATN/IPS Data Service (Future)
The ATN/IPS data service will be a high availability ACD data service, protected by
priority and pre-emption. Depending on the requirements imposed by the end-to-end
ATN/IPS security architecture the service may also be protected by authentication
provided by the security gateway. The service is intended to support the same
applications as ATN/OSI data service, but using ATN/IPS network protocol defined in
ICAO 9896. The interface to CMU is expected to be based on Ethernet but ARINC
429 may also be used.
The voice service provides one or two channels of priority voice to the cockpit (ACD).
In addition, the following security provisions are provided: ciphering on the air interface
to provide confidentiality, and use of PINs on ground to air calls to restrict access to
calling the cockpit from non-authorized callers. Optionally the VoIP component may be
authenticated through an air-ground VPN established between the air and ground
security gateway functions. The interface to the flight deck avionics is typically analog
4 wire voice and ARINC 429 control from an MCDU or similar function. Both the air
and ground side interfaces are typically the same as for Classic Aero, including
addressing using the ICAO 24-bit aircraft address, and hence the use of Classic Aero
or SBB for voice is typically transparent to pilots and ground users. Calls to and from
the cockpit are protected by priority, precedence and preemption - in the AES as well
as on the network.
Priority IP Service
The Priority IP Data service supports IP based applications that require a timely and
prioritized service compared to the non-priority SBB IP service. The priority IP service
can be offered both in ACD and AISD. Examples are:
Flight data downloaded after a critical event
Access to ATN over satellite.
Both fixed rate (streaming) and variable bit rate (standard) IPv4 services are provided.
The standard IP service class is a variable bit rate IP service, also known as
background class. Capacity is allocated dynamically by the network on the basis of
the user’s demand, the user’s current link quality and the competing demands of other
users sharing the same L-Band frequency in the same spot-beam. The background
class connection provides reliable in-order delivery over the satellite, i.e. any data lost
due to random errors on the radio link is automatically retransmitted and re-ordered by
the SBB infrastructure before being presented to the user.
The streaming class IP service is a fixed bit rate IP service. The user sets the bit rate
at the start of the connection and this rate is fixed for the duration of that connection.
This class is designed for real-time applications that benefit from low delay variations
but can tolerate a somewhat higher packet error rate.
The priority IP service is an optional service and as such is not governed
by this MOPS. If the priority IP service is to be used for ATS
communications, the definition and approval of such solution is user
Links Archive Navigation Previous Page Next Page