Home' RTCA Documents for Review : DO-343B Contents © RTCA, 2018
use the VPN. AES supporting ATN/OSI (including AES supporting both ATN/OSI and
ACARS) are required to use the VPN.
Note: This prioritized service is optimized for ACARS, and provides appropriate priority
and preemption capabilities for ACARS messages. Actual approval of ACARS
communications for AMS(R)S, especially ATS communications, is the responsibility of
the user ANSP.
22.214.171.124 ATN/OSI Data Service
The ATN/OSI data service is a high availability data service with priority and pre-
emption supporting ATS applications at RCP130 and RSP160 performance levels. It
is intended to support ATS ATN applications using the ATN/OSI network protocol
(ICAO 9880). A similar performance level to VDL Mode 2 is provided except that
coverage is worldwide and greater capacity is available. The ground side interface to
ANSPs and CNPs is the same as for VDL Mode 2 and is defined in the ICAO ATN
manual. The airside interface to the CMU is an evolution of the equivalent ACARS
CMU to SDU interface. The ATN/OSI data service is delivered via a VPN between the
ground and aircraft to provide enhanced protection of messages from tampering.
126.96.36.199 Voice service
The voice service provides two channels of prioritized voice to the cockpit. 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. The ground side interface is via the PSTN whilst
the airside interface is typically analog 4 wire voice and ARINC 429 control. Both the
air and ground side interfaces are 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 transparent to pilots and ground users.
The first voice channel is provided in the Circuit Switched (CS) domain, whilst the
second voice channel is provided in the Packet Switched (PS) domain using a VoIP
server within the SBB network. The Packet Switched voice service is provided either
via a VPN (Enhanced PS voice) or not via a VPN (Standard PS Voice). If the AES is
using the VPN for ACARS or ATN/OSI then it is required to use the VPN for PS Voice.
188.8.131.52 Prioritized IP Service
The Prioritized IP Data service supports IP based applications that require a timely and
prioritized service compared to the non-priority SBB IP service. Examples of this might
New AOC applications.
Meteorological and Aeronautical Information applications.
Flight data downloaded after a critical event.
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. It is 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 standard 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.
Note: This prioritized service is optimized for IP message traffic of various kinds, and
provides appropriate priority and preemption capabilities for such IP messages. Actual
Links Archive Navigation Previous Page Next Page